Communicable diseases [full issue]

• • • • • • • • • • • • • • • COMMUNICABLE DISEASES • • • • • • WORLD HEALTH THE MAGAZINE OF THE WORLD HEALTH ORGANIZATION • NOVEMBER 1980 7 Could the Great "Plagues" Recur? by P. L. Bres .......... Cover: Infections— a threat to life and health. Design by Peter Davies. IX ISSN 0043-8502 World Health is the official illustrated magazine of the World Health Organization. Editor: John Bland Deputy Editor: Christiane Viedma Art Editor: Peter Davies News Page Editor: Lalit Thapalyal World Health appears ten times a year in English, French, Portuguese, Russian and Spanish, and four times a year in Arabic and Persian. Articles and photographs not copyrighted may be reproduced provided credit is given to the World Health Organization. Signed articles do not necessarily reflect WHO's views. World Health, WHO, Av. Appia, 1211 Geneva 27, Switzerland. Contents WHO's Communicable Diseases Programme by Albert Zahra 3 The World on 'Flu-Watch by Martine Allain-Regnault . 10 Diarrhoea! Diseases by Dhiman Barua 14 Polio — A Controllable Disease by Joseph L. Melnick 18 Sexually Transmitted Diseases by Donald Gould 23 Acute Respiratory Diseases by Sir Charles Stuart-Harris . 26 News Page 30 WHO's Communicable Diseases Programme Given political will and commitment, and using knowledge that is already in our possession, we can significantly reduce the present unacceptable morbidity and mortality from communicable diseases by Albert Zahra r Edward Jenner's prediction in 1801 that smallpox and its recur- ring toll in deaths, disfigurement and disability would ultimately be exterminated from the face of the earth has become a reality of our day fol- lowing its global eradication. This uni- que achievement has naturally aroused world-wide interest about what progress is being made in the field of communi- cable diseases control and which other communicable diseases are being at- tacked by the Member States of wHo. This issue of World Health concentrates on certain priority communicable dis- eases of bacterial and viral origin, which form part of the current programme of work, and does not, therefore, include references to protozoal diseases (such as malaria) or other parasitic diseases (such as river blindness, schistosomiasis and sleeping sickness). Like other serious and continuing health problems, communicable diseases demonstrate the relationship between health and socioeconomic development; in particular, they reflect the interrela- tionships between infection, malnutri- tion and unregulated fertility, aggravated by poverty, an unhealthy environment and a paucity of health services. A study undertaken in 1973 in Central and South America of deaths in children under five years of age showed that, of the total deaths, 58 per cent were associated with infectious diseases; of these, the major killers were diarrhoeal diseases (49.5 per cent) and respiratory infection (28.2 per cent), but measles (10.3 per cent) and a variety of other infectious diseases (teta- nus, whooping cough, diphtheria, tuber- culosis) were also important causes of death. The association of nutritional When coupled with malnutrition, as in this Indonesian child, whooping cough is still one of the killer diseases. ( Photo WHO/EPI/L. Matlovski) deficiency and/or low birth weight with these infections was very striking—about 53 per cent of the deaths were in imma- ture or malnourished children. During the famine in the Sahel in Africa, the case fatality for measles was estimated to be up to 50 per cent, and in other parts of tropical Africa it is seven to ten per cent, still very much higher than in most parts of the world. WHO's Sixth Report on the World Health Situation, 1973-1977, shows, in its global analysis, that of some 122 mil- lion babies born each year roughly ten per cent will die before reaching their first birthday, and another four per cent before their fifth birthday. Some 21 million babies are born each year with low birth weight—that is, less than 2,500 grammes—which makes them acutely susceptible to subsequent infec- tions and malnutrition. Regrettably, the basic cause of the majority of these deaths and illnesses is one or other of the communicable diseases. In later years, other communicable diseases take their toll, causing severe illness, loss of work- ing ability, or death : tuberculosis, sex- ually transmitted diseases, trachoma, leprosy, zoonoses and food-borne dis- eases, hepatitis, and a number of other bacterial and viral infections with en- demic or epidemic potential. There are still real threats of epidemics and pandemics in the world from in- fluenza, cholera, dengue haemorrhagic fever, Lassa, Marburg and Ebola virus diseases, Rift Valley fever, encephalitis (including Japanese B encephalitis), and yellow fever. Foci of plague, typhus, relapsing fever, rickettsioses and tulare- mia persist. An inadequate epidemiologi- cal surveillance, neglect in applying proper preventive measures and man- made disturbances of the ecological conditions or other factors may well lead to epidemics. Also of increasing concern are nosoco- mial, or cross infections in hospitals and other communities, as well as acquired resistance and natural insensitivity to chemotherapeutic agents. In the coming decades, a close watch will have to be kept on several emerging problems, in particular those associated with rapid ur- banization, the expansion of travel and population movement, and the increas- ing trade in human and animal foods within and between countries, all of which have increased the risk of intro- duction or reintroduction of exotic diseases. The 1978 Declaration of Alma-Ata on Primary Health Care stressed that mea- sures for communicable disease control should form part of primary health care, being, as they are, inextricably bound up with the provision of comprehensive health services, the promotion of clean environment and water, and the applica- tion of appropriate agricultural and nutritional policies. The programme of work on communicable diseases accord- ingly focuses on those diseases or groups of diseases that unquestionably com- mand priority attention, and for which proven effective methods for prevention and control exist or for which there is demonstrable potential for research. Preventable childhood infections At present, fewer than 10 per cent of children born in developing countries are being fully immunized. The aim of the Organization's Expanded Programme on Immunization is to provide, in close col- laboration with UNICEF, immunization against diphtheria, measles, poliomyeli- tis, whooping cough, tetanus and tuber- culosis to each of more than 80 million children born each year in developing countries, and thereby reduce their morbidity and mortality. These diseases 3 WHO's Communicable Diseases Programme Left: This medieval French painting shows nuns and priests applying leeches to bleed plague victims—a medical practice that probably shortened more lives than it saved. ( Photo WHO) Right: Emergency rehydration of cholera patients at a dispensary near Calcutta, India. Proper use of oral rehydration can reduce by 70 per cent or more the need for intravenous fluid to treat cholera and other acute diarrhoeas. ( Photo WHO/D. Henrioud) are responsible for over five million deaths each year, and an equal number of children are disabled through para- lysis, stunted growth, deafness, blind- ness, and so on. Diarrhoea! diseases Another programme closely con- cerned with the health of infants and young children is that of Diarrhoeal Dis- ease Control—though it is also aimed at preventing these diseases in adults. In developing countries, they can cause nearly a third of the deaths in the young, resulting in several million deaths each year in Africa, Asia and Latin America. Diarrhoea is by far the major single killer and is also responsible for retarding the growth and development of those who survive, because of the associated malnu- trition and the vicious circle it sets up. Oral rehydration therapy is proving to be a valuable life-saver. Acute respiratory infections Acute respiratory infections are also major killers of young children, but oth- er age groups too are heavily affected, with a global estimate of 2.2 million deaths every year. Pneumonias, bacterial and viral, account for about five per cent of all reported causes of deaths. The availability of safe and effective vaccines is at present limited to those against diphtheria, measles and pertussis, though field trials are being carried out on a polyvalent pneumococcal vaccine effec- tive against the serotypes of Streptococ- cus pneumoniae that are predominant locally. The aim of the Programme of Acute Respiratory Infections is to bring effective treatment to the patient at the periphery through primary health care and thereby cut down on pneumonia deaths. Tuberculosis The anti-tuberculosis programme was one of the main programmes at the birth of WHO. The disease shows itself in many different forms affecting all parts of the body—the brain, the lungs, the in- testines and other organs, and the bones; at least 3.5 million people develop tuber- culosis each year, and more than half a million die from it. The objective of tuberculosis control is to break the chain of transmission of the infection. This is achieved by detecting the sources of the infection, as early as possible rendering them non-infectious by chemotherapy given in the patients' homes rather than in special institutions or sanatoria, and by providing BCG vaccination. BCG vacci- nation is included in the Expanded Pro- gramme on Immunization in infants and young children. Leprosy The programme against leprosy was another early one among WHO's activi- ties. Here, too, there has been a consider- able change in control methods, away from the now obsolete institutional approach. Leprosy should no longer be considered as a disease apart, but as any other public health problem caused by a bacterial infection. The situation was long beset by difficulties in management and the development of resistance to the main therapeutic agent, dapsone. Recently, increasing national and inter- national support has materialized for leprosy control and research, permitting the programme to develop further as part of the community health services. Research efforts include, on the one hand, the development of an anti-leprosy vaccine with an antigen of killed M. leprae preparation derived from armadil- los (bizarre burrowing animals found in South America) infected with the dis- ease, and, on the other, the search for more effective drugs or for various com- binations of effective anti-leprosy drugs such as rifampicin and clofazimine with dapsone. Sexually transmitted diseases The frequency of infections of sexually transmitted diseases is increasing in most countries, with a general shift to the 4 teenage group. Gonorrhoea, syphilis and nongonococcal genital infections are now more common in many countries. The picture is complicated by the ap- pearance of a strain of the gonococcus bacteria that does not respond to the usual penicillin treatment. The aim of our programme is to identify the causa- tive social and behavioural patterns re- sponsible for the present situation and to develop greater community awareness, surveillance and action programmes focusing on important groups such as pregnant women and high risk groups. Emphasis continues to be placed on the training of professional and auxiliary health and social workers, and on health education. Prevention of blindness The Programme for the Prevention of Blindness is beginning to attract much needed support. It has been estimated that there are about 42 million blind peo- ple throughout the world. Over 30 mil- lion of them live in developing countries, where trachoma (a communicable dis- ease of the eyes associated with dust, flies and direct infection) and river blindness or onchocerciasis (transmitted through bites of Simulium blackflies)—both potentially avoidable—are major causes of blindness, along with xerophthalmia (as a result of vitamin A deficiency), cataract and accidents. In other words, 30 million people are needlessly blind. The Programme seeks to introduce rela- tively simple measures for coping with a good part of these cases of blindness resulting from both communicable and non-communicable causes, as part of national health programmes. Outlook for the future Experience shows that, whatever the theoretical possibilities, the practical possibilities of eradicating diseases other than smallpox are not yet attainable. There is certainly no room for pessim- ism, but neither is there any room for complacency. Significant advances have been made in immunology, vaccine and drug devel- opment. In diarrhoeal diseases, including cholera, there are promising develop- ments of new anti-secretory drugs and potential vaccines. Significant progress is also expected on vaccines against typhoid fever, meningococcal meningitis, bacterial pneumonias, respiratory syncy- tial viruses and hepatitis. While our range of chemotherapeutic drugs against bacterial and parasitic diseases has become impressive, the efficacy of syste- matic antiviral agents has until now been viewed with scepticism. However, today's experience with interferon, amantadine and adenine arabinoside has opened up a promising vista for antiviral therapy in infectious diseases and in cancer. Revolutionary progress is being made by scientists who, through genetic engineering, can now make certain bac- teria secrete useful products ; as a result, interferon, insulin and other hormones or antibodies will very soon be available widely and cheaply to mankind. Of equal importance is the timely collection, analysis and dissemination of information about diseases and control measures. WHO has a major re- sponsibility towards Member States for building up epidemiological surveillance, emergency services and trained man- power on a world-wide basis. Notwithstanding these new develop- ments, a note of caution is indicated. While vaccines and chemotherapy are undoubtedly highly cost-effective tools of public health action, and lend them- selves to further improvement, adminis- tering them to whole communities or groups at risk poses big problems. No immediate dramatic results must be looked for, since control of many com- municable diseases cannot go ahead of the provision of primary health care ser- vices, or the improvement of nutrition, environmental conditions and socio- economic levels. Eventual success will depend to a great extent on community understanding, participation of the fami- ly, and in particular the involvement of the mother as the front-line health worker. A healthy trend is to be seen in the more dynamic participation of the world community in concerted efforts to raise the present quality of life. This is exem- plified by the several national and inter- national endeavours to attain goals such as those set by the UN Decade for Wom- en (1976-1985), the International Year of the Child (1979) and the International Drinking Water Supply and Sanitation Decade (1981-1990), all of which relate and interlink with the momentous Declaration of Alma-Ata in 1978, which sealed the commitment of Member States of WHO to primary health care. In the coming decades, the majority of developing countries, and several devel- oped countries too, will continue their struggle against infectious and parasitic diseases and accord them first priority. This issue of World Health focuses on strategies against priority diseases and groups of diseases. Given political will and commitment, and by the determined application of knowledge already in our possession, we can significantly reduce the present unacceptable morbidity and mortality from communicable diseases in any country, through Primary Health Care and the strategies being formulated for "Health for All by the Year 2000". ■ 5 • wiluamaimuomm mV 4 VIMMINMININ/ 11 ie CUICII3, 11 Enwicummi0 11 vt I . . v **- 4*,4IL.4. i ■ II -At • Ili • • • ,W . • t aia. O! .11/: j4404.1111 .6, 40t. pa , i , ........ „, ..,........! ,,,,i . 1100/111 •■ iv. WS Mak ...L. - ' ,•1' ■41., „We ill. -0-- 9g,„ 1 _ tt7iti2 the . dead with a Could the Great "Plagues" Recur? Vaccination campaigns and improved antibiotics seem so far to be keeping the big epidemic diseases under control. But under certain circumstances they could scourge the world again. We cannot afford to lower our guard by P. L. Bres ince ancient times, not a single century has elapsed without some terrible epidemic disease cutting a swathe through entire popula- tions of the world. The worst epidemics have been caused by five diseases which people recognized simply as "plagues" : cholera, smallpox, plague itself, typhus and yellow fever. When such epidemics extend to more than one continent, we speak of them as pandemics. The threat that these "plagues" pose to mankind has considerably lessened during recent decades : smallpox for one has been totally eradicated, and the others have been kept in check. Given the present state of the world, is there a risk of them returning to the offensive? Influenza is not included among these "plagues", but it too has caused pan- demics. What does it have in store for us in the coming years? Could other dis- eases somehow turn into "plagues - ? For the present we can only reply to such questions with an educated guess. Al- though much progress has been made in medicine and epidemiology, these sciences have still not enabled us to fore- cast the future with absolute certainty. Throughout recorded history up to the Middle Ages, the great epidemics were During the Great Plague of 1665, the London Bills of Mortality recorded over 68,000 fatali- ties from "the Black Death" in the space of seven months. These contemporary drawings convey some of the horror of a national calamity whose origin nobody then could understand. ( Photo WHO) highly mysterious events. They were seen as a curse sent from heaven in reprisal for some offence that had been commit- ted, and could only be exorcised by cer- tain appropriate rituals. Historians de- scribed each one indiscriminately as a "plague", and it is not always possible to recognize which disease was involved. From the 16th Century onwards, clinical descriptions in Europe started to be more precise. The London Bills of Mor- tality, begun around 1532, constitute the first documents which are of real statisti- cal value to epidemiology. The era of medical microbiology, her- alded in the middle of the 19th Century by the work of Louis Pasteur (1822- 1895), at last enabled the microbes which cause epidemics to be identified. Robert Koch discovered the cholera bacterium in 1883 and Alexandre Yersin that of plague in 1894. Two years later, Emile Roux and Yersin demonstrated the role played by the rat as a reservoir of the pla- gue bacillus, and within the same year Paul Louis Simond proved that it was transmitted to man by the rat-flea. The causative agent of certain epidemic dis- eases remained mysterious at this period, but scientists were already beginning to think in terms of viruses—microbes even smaller than bacteria and invisible in the ordinary microscope. In 1901, Walter Reed and James Car- roll showed that yellow fever was trans- mitted by a virus, although this was only isolated in 1927, through inoculation in monkeys. In 1906, Enrique Paschen used an ordinary microscope to observe quan- tities of virus forming "elementary bodies" in the infected cells of smallpox pustules. The role of the louse in typhus epidemics was only brought to light in 1909, by Charles Nicolle, and the causa- tive agent—a species of Rickettsia, an or- ganism resembling both bacteria and viruses—was described by Henrique da Rocha-Lima in 1916. The influenza virus was first isolated only in 1933. Plagues past and present For centuries—until 1817—cholera remained in its country of origin—the delta of the Ganges, on the Indian sub- continent, and in neighbouring areas. It strikes down people of all ages, children and adults alike. If they are not treated, between 10 and 50 per cent of the cases die, sometimes in a matter of two or three days through cardiac arrest follow- ing incessant diarrhoea and vomiting. Since the early 19th Century, cholera has invaded Asia, Africa, Europe and the Americas in the course of six great pan- demics triggered off respectively in 1817, 1826, 1840, 1863, 1883 and 1892. Each one lasted some ten years. The final, seventh pandemic has still not finished. It began in 1961 on the island of Celebes, Indonesia, and penetrated Africa in 1970, but has so far spared the Americas. This seventh pandemic could turn out to be the longest. Today cholera tends to remain endemic in the affected areas. Smallpox was already known in India, China and Egypt more than 3,000 years 7 Could the Great "Plagues" Recur? before the Christian era. There were many outbreaks in Europe during the Middle Ages. Introduced into the Ameri- cas by the European explorers of the 16th Century, it decimated the native "Indian" populations. In the 18th Cen- tury, smallpox caused between 1,000 and 3,000 deaths a year in London alone. In spite of the vaccine discovered in 1798 by the English physician Edward Jenner, smallpox remained endemic for more than a century and a half in a great many countries. In 1967, when WHO launched its world-wide programme of eradication, there were an estimated 10 to 15 million cases and two million deaths every year, while 33 countries were still infested. In a global effort that is without precedent, it proved possible to eradicate this killer disease thanks to the active tracking down of cases and improved use of the vaccine. The last known case dates from 26 October 1977, in Somalia. Eradica- tion of smallpox had been achieved in the space of ten years. Many epidemics of the plague have been described in the manuscripts of an- cient times. During the Christian era, the first known pandemic made its appear- ance in 542 A.D. It ravaged the Mediter- ranean world for fully 50 years. The second pandemic was the terrible Black Death of the 14th Century. Imported from India through the seaports of Eu- rope, it scourged Europe for no less than four centuries and is thought to have killed 25 million people. Constant war- fare and the besieging of cities often caused fresh epidemic outbreaks because of contagion among the trapped inhabi- tants and the uncontrolled growth of the rat population. In 1665 the London Bills of Mortality recorded 68,596 deaths caused by the Black Death (The Great Plague) in that city alone within seven months. The pla- gue manifests itself not only in its bubon- ic form—which is transmitted to man by the rat-flea—and its complication known as primary septicemic plague, but also in the shape of primary pneumonic plague which is frighteningly contagious through the respiratory tract. The third pandemic started out from Canton, in China, in 1894. It swept through every continent in five years and is still in action. Today we believe the plague stemmed originally from Central Asia and has created secondary foci for itself on the different continents. Epidemic typhus is also of very ancient origin, and has only been distinguished from similar diseases since the 18th Cen- tury. Transmitted by the louse, it has been called "prison fever", "war fever" and "famine fever" since it is so often as- sociated with miserable human condi- tions everywhere in the world. Generally the fever lasts for some two weeks accompanied by great weakness ; some 20 per cent of the victims die, but the mortality can reach 60 per cent in old people. Typhus decimated the armies of Napoleon during the retreat from Mos- cow in 1812. Between 1918 and 1922 it has been estimated that there were 30 million cases and three million deaths in Russia. Today many limited foci remain in mountainous areas of Africa, the Americas and Asia. In Eastern Eu- rope a form of typhus called Brill-Zinsser disease still persists; it has a very long period of incubation, and can flare up again after long remaining dormant. When yellow fever raged The history of yellow fever starts in the 17th Century with the colonization of the Americas. Some people believe that the virus existed already in the Caribbean islands, others that it was introduced by the African slave trade. Epidemics which terrified sailors and settlers alike wrought havoc for three centuries in the seaports of the American coast, from Buenos Aires to Quebec, as well as those of the African shore from Senegal to Angola. The symptoms of jaundice, hae- morrhaging and, finally, black vomiting were all too well known, and mortality could be as high as 80 per cent of cases. In Philadelphia in 1793, some 11,000 cases were reported, of whom 4,000 died, out of a population of 40,000 inhabitants. A first attempt to cut the Panama Canal between the Carib- bean and the Pacific was a disaster as a direct result of yellow fever and malaria. After certain control measures were taken against the domestic mosquito Aedes aegypti, which transmits the dis- ease, urban yellow fever had disappeared from the Americas by 1934. However we know now that the original and per- manent focus of jungle yellow fever is in the equatorial forests of the Americas and of Africa. Fortunately a very effec- tive vaccine was prepared in the United States by Max Theiler in 1937. Today there are renewed fears that a reinfesta- tion of the towns of South America and Central America by the Aedes mosquito could trigger off fresh epidemics. Influenza deserves to be added to the list of "plagues" that beset mankind. It has certainly existed since antiquity, but the pandemic of 1889-1890 is the first one that can be identified with certainty. Starting off from Siberia, whence its name "Russian 'flu", it invaded the whole world in the course of one winter. The pandemic of 1918-1919 was de- scribed by Sir Christopher Andrewes as "the greatest scourge this planet has ever known". It caused at least 15 to 25 mil- lion deaths in one year—that is, between three and five times more than the total death toll in World War I. People called it "Spanish 'flu" but a more accurate name would have been "Chinese" or perhaps "American". It first appeared in Canton in February 1918, then in the military camps of the United States in March. By April it had followed the American troops when they embarked for service in France, and had begun its work of decimating the armies and civil populations of Europe in May and June. Presently the whole world was affected. It devastated each country in three distinct phases. During the summer of 1918, it sent its victims reeling to bed for three days. By that autumn, the second wave was far more severe and tended to cause pneumonia which killed the victim in a matter of three days. The third wave, no less vicious, came in January 1919. The panic these waves caused was all the greater because the virus responsible was only found in 1933. There have been two other pandemics, in 1957 and 1968, which were equally swift and widespread. Although fortu- nately less serious than in 1918, the first one caused 60,000 deaths in six months in the United States alone, and the second caused another 80,000 deaths. A vaccine exists against influenza—but, as another article in this issue shows, it has to be changed every time a new strain of 'flu virus makes its appearance. Epidemiology—the study of the fac- tors determining the frequency and dis- tribution of diseases in the community— made only slow progress up to the start of this century. Now, thanks to modern bacteriology, virology and parasitology, it is possible to understand the mechan- ism of epidemics much more clearly and, to a certain degree, to forecast their ap- pearance and magnitude through orga- nized surveillance, serological studies 8 and ecological investigation. The situa- tion thus seems to be getting better, now that the measures available to us include not only vaccines against the epidemic diseases but also antibiotics against bac- teria and perhaps soon against viruses too. Steadily improving living standards, education, nutrition, personal hygiene and sanitation offer us further lines of defence against epidemics. However there are still a number of factors which favour the spread of epi- demic diseases. Foremost among these factors is the natural evolution of these infections. Such diseases as cerebrospinal meningitis, typhoid, bacterial dysentery and diphtheria cause epidemics which are usually limited in scale but which risk getting out of control because they can develop resistance to present-day antibiotics. Individual and collective measures of hygiene then become our last line of defence. A rat meets its doom in Ecuador during an anti-plague campaign. Many countries still record cases of plague—relics of the third great pandemic that began in 1894. ( Photo WHO) Epidemic diseases may disappear of their own volition. Sweating sickness, a disease recognized as epidemic in the Middle Ages, has vanished in this way, and so has the form of paralysis agitans known as von Economo, which caused much suffering between 1916 and 1926. The other side of the coin is that new dis- eases may arise : this is the case with diarrhoeas caused by Campylobacter, pneumonia caused by Legionella (Legionnaires' disease), and the viral haemorrhagic fevers known as Lassa fever, Ebola fever and Marburg fever, all of which have appeared in the course of the last ten years. Microbes which cause familiar dis- eases can change their constitution and become either more or less virulent. The seventh pandemic of cholera was caused by the El Tor vibrio, which differs from that of previous pandemics in that it is more resistant in water and is excreted over a much longer period by the victim; these changes tend to make it an endemic disease. The 'flu virus can change in severity during successive waves of an epidemic. If the risk of epidemics has been les- sened by advances in knowledge, it can also become more acute because of changes in our life-styles. Consider, for instance, the changes that have taken place in the frequency, speed and dis- tance of our travels, our mass transport systems, the attendance of thousands of individuals at various forms of mass events, the migration of populations, the industrial preparation of food, and various ecological upheavals which affect animal vectors and reservoirs of microbes. Apart from these man-made situations, there are natural events such as floods or droughts. The history of viral hepatitis clearly shows how social and economic factors can make a contagious disease by turns either endemic or epidemic. In some countries, over-population and the lack of hygiene, water and food can create ep- idemics of hepatitis A transmitted by the fecal-oral route. Travellers then carry the infection with them to areas where the incidence is normally slight. In other societies, the use of poorly sterilized syringes, in particular among drug dependents, and such practices as the cutting of ritual scars, tattooing and prostitution can be responsible for epi- demics of hepatitis B. This disease is in- creasingly being transmitted to people who have only casual contact with medi- cal personnel and other carriers. The future evolution of the big epi- demic diseases will depend on the bal- ance between such factors as these. The old "plagues" are now well on the way to extinction as our preventive health activ- ities continue to make progress. Any new epidemic diseases ought similarly to lend themselves to control. The case of influenza is rather special; it may well prove to be, as W.I.B. Beveridge main- tained, "the last scourge" to threaten us with any severity. When all is said and done, our defence against the major epidemic diseases rests on three foun- dations : vigilance in epidemiological surveillance, progress in developing new antibiotics, and ever higher stan- dards of health. ■ 9 The World on 'Flu-Watch The sixth great influenza pandemic of the 20th cen- tury could break out at any moment. A close-knit network of 103 monitoring centres in 73 countries of the world is standing by permanently on "red alert" by Martine Allain-Regnault L--- rom one month to the next, the latest breed of influenza virus may make its appearance somewhere in the world. This one will replace the Hong Kong strain and its many deri- vatives which have been in circulation since 1968. On the eve of what is expect-' ed to be the sixth pandemic of 'flu of the 20th century, a world-wide surveillance system is standing by to track the most widespread and most elusive virus that has ever existed. There has never been a more unstable, more lethal or more cost- ly virus—and no doubt the world will never really get rid of it completely. As- tonishingly agile in its genetic shift and drift (mutations), and with a great variety of animal hosts, this virus is highly un- likely to disappear from the planet, even if every health system in the world unites in action against it. All the same, the progress made in genetics and immunology, joint action on the part of clinicians, virologists and veterinary experts, and above all the set- ting up of a global surveillance network on truly Interpol lines offer the hope that mankind and the 'flu virus can cohabit with the minimum of suffering, and can avoid the ravages wrought earlier in the century which many people remember only too well. It is worth recalling that when the virus changes to the point where it slips through the preventive net extended by vaccination, the 'flu epi- demics which send close on one-third of the world's population to their beds every ten years actually kill more people than most wars. And in the industrialized world, these epidemics rank first in the list of mortality linked with communicable diseases. This high cost in human lives, in work- days lost, in dollars, roubles, yens, marks, pounds, francs or whatever, obliges all countries, without exception, to take a permanent interest in the dos- sier of influenza in all its various aspects, of which the most vital and most recent is undoubtedly the world-wide monitor- ing system among men and animals, in the hope of recording with the minimum of delay any change in the virus. Virus without frontiers We are now suffering from the last contortions of the "Hong Kong" virus. First discovered in 1968 in that tiny and congested "Western" toe-hold on the flank of Asia, this virus ravaged the entire world within two or three years. But by 10 The high cost of influenza in human lives, in work-days lost, obliges all countries to keep a close watch on the progress of this disease. ( Photo WHO/P. Boucas) the end of 1971 it had also exhausted its chances of spreading further in its origi- nal form; the world had in effect become virtually immunized against it. But no matter; by the following year Hong Kong 'flu had changed sufficiently to be able to reinfect its former victims. Recognized in its new form in the United Kingdom, it received the name "England". One year later, at Port Chalmers in Australia, a new derivative of the Hong Kong variety was identified, and reached Europe soon afterwards. In 1975 came "Scotland", and in 1976 "Victoria". The same year saw the return of an old ac- quaintance—the Spanish 'flu of 1918. In 1977 came the "Texas" strain; about this time a strain reappeared which had plagued mankind from 1947 to 1957 and which would from now on attack young people born since 1957 and therefore lacking any immunity. Today we can say the Hong Kong-derived strains are at their last gasp; and we are therefore standing by for the next great change, somewhere in Europe, Africa, Asia, or the Americas. This short history testifies both to the ubiquitous nature of the virus and to the speed with which we can today identify every important new variation and try to take steps against it. Ever since 1947, WHO has been collecting and disseminat- ing information from all over the world about influenza foci, epidemics and the current strains of virus. Geneva is the collection centre for all the records col- lated by the two great 'flu monitoring centres (Atlanta, Georgia, in the USA, and London in the UK), and by the 103 national centres scattered through 73 countries. This system enables us to maintain a permanent record of all the data from national laboratories which isolate and identify the different strains. In 1976, when the swine influenza virus called Spanish 'flu—cause of so much suffering in 1918—made its reap- pearance in New Jersey, USA, it was identified very rapidly. One week later the specialists all over the world had been warned. By the third week the inac- tivated antigen of the virus was being dis- tributed to all national centres, along with specific anti-serums enabling this virus to be distinguished from other strains. At the same time, vaccine strains were being put at the disposal of a number of manufacturers. In order to check an epidemic, a series of indicators have been chosen whose use varies from country to country. Notifica- tion or declaration of the disease is obli- gatory in some countries (the USSR for instance). In the UK, the authorities rely on a network of specialists who act as "watchdogs" in each region. Mortality is only used as an index if it is collated with great regularity, week by week, as in the USA or the UK. It enables observers to note a "peak" or sudden increase in deaths from this cause, and thus to give the alert. Biological diagnosis depends on the examination of serum and isolation of the virus. In France, for instance, 27 laboratories keep a check on the num- bers and types of virus isolated each week (between 1 October and 1 May) and this information is transmitted to one of the two world reference centres. Thus the evolution of each 'flu strain can in theory be accurately traced. Absenteeism can be monitored in the larger industrial companies, while school absenteeism is one of the best indices. The speed with which measures can be taken on a world-wide scale is quite remarkable, yet it is still not sufficient to check an epidemic at the outset. There are two reasons for this. Firstly, within three or four weeks—quite a short space of time—the virus has already made inroads and caused victims. Secondly, 11 The World on 'Flu-Watch Left: Hong Kong, where a "new" influenza virus was identified in 1968. It ravaged the entire world within two or three years. Today the Hong Kong-derived strains are at their last gasp, and flu-watchers are standing by for the next great change in the virus. ( Photo WHO/D. Henrioud) Right: Pigs are just one of the animal reservoirs that can harbour the elusive 'flu virus. It can lie dormant in these animals before recombining with animal strains to give birth to a new virus that can return to plague mankind. ( Photo WHO/T. Takahara) monitoring is still not quite as "global" as we could wish. Was the Asian 'flu known as "Hong Kong" really born in Hong Kong? Or was it simply that the new virus was first isolated there one day in July 1968? The second hypothesis is surely the right one. Twelve years ago Hong Kong was still the first "Western" point of access for news from China. Observations and data received since then have made it seem likely that the virus strain bearing the name Hong Kong in fact stemmed from the heartland of China; but since that country did not at that period form part of the international monitoring network, there was no way of knowing this fact at that time. Since 1976, China has been supplying information from its two existing na- tional laboratories, and exchanging data with laboratories in many other coun- tries. News has been scarce from other parts of the world, and it goes without saying that the necessary laboratory equipment for monitoring 'flu, important as it is, has to take second place to a country's national development and depends on the resources it has available for public health. So it is surprising to find that no fewer than 49 monitoring centres already exist in developing countries compared with 54 in the highly indus- trialized countries. For mankind's 'flu- watch to be really effective, every last corner of the world ought to be as well organized as the industrialized countries, and this is not yet the case. But another factor is essential for 'flu surveillance to be total—animals too have to be moni- tored. Pigs and ducks — the animal reservoirs Careful study of the "cycles" of 'flu epidemics suggests that a given virus will flourish in all its different varieties for about 10 or 12 years. After that period, a genetic shift causes a new virus to ap- pear. Looking further back in time, we can estimate that a virus may be expected to return in its initial form every 70 or 80 years, that is, when the entire popula- tion, with a life expectancy of 70 years, has been born since that particular virus made its last appearance. It is on the basis of this reasoning—hypothetical but well founded—that we are now awaiting the return of a pandemic that could be as widespread as that of 1918. The only problem is to explain where these viruses have been hiding during their long periods of silence. The first hints, and subsequent expla- nations, came from veterinary medicine, virology and animal genetics. It has been discovered recently that, if certain 'flu viruses are proper to animals, the human viruses can also be transmitted to some animals and lie dormant in them for a long time without changing, but may re- combine with certain animal strains to give birth to a new virus. Thus a whole series of combinations are possible and we have no means of knowing which one will carry the day. 12 Several disturbing observations were reported in the course of an international symposium devoted to animal and human 'flu strains, which was held at the Veterinary School of Maisons-Alfort, France, in September 1979. Among oth- er things the symposium learnt that there was now proof, as had been expected, that pigs and ducks could be both reser- voirs and carriers—sometimes perfectly healthy carriers—of viruses that are harmful to man. The American specialist Virginia Hinshaw, for instance, reported that 67 per cent of the ducks in her coun- try are infected. These findings have been confirmed with various percentages in a number of countries, and particularly in France where the Marquenterre bird reserve in the Bay of the Somme har- bours 300 species of migratory birds and works in collaboration with Professor Claude Hannoun at the Pasteur Institute in Paris. As regards pigs, Professeur Hannoun compared serological studies made in both animals and man, and was able to show that the Soviet virus H1N1, which disappeared in 1947, had shown up again in 1977 among pigs in France before making its appearance in man. Another example which substantiates the hypothesis of 'flu transmission between animals and man is the well- known outbreak at Fort Dix, New Jersey, in 1976. Young recruits at this US military camp fell victims to a sudden 'flu epidemic, and one of them died. Two viruses were detected. The main one belonged to the strain then predominat- ing throughout the world—A/Victo- ria/3/75 (H3N2). But in five cases, in- cluding the man who died, the virus was identified as swine virus Hswl N1, which is very widespread throughout the United States. Serological studies carried out among former 'flu victims have shown a rela- tionship between this swine 'flu virus and that of the 1918 pandemic. As a result of the Fort Dix episode, WHO undertook some vast enquiries which all showed the same results. People of over 50 years of age to a large extent had antibodies relat- ed to the Hswl N1 strains which were prevalent in 1918. Other observations are tending to reinforce this theory. In the light of all these various observations made all over the world, it seems more and more certain that various animals act as reservoirs for human viruses, per- mitting them to reappear after several decades slightly modified or even un- changed. However, to date the formal proof that a true animal virus can pass to man is still lacking. In any event, this interface between two aspects of epidemiology fascinates doctors and veterinarians alike, who are all firmly convinced that the world-wide monitoring of both human and animal diseases ought to be strictly coordinated. It remains to be seen from which animal species will come the 'flu virus of the sixth great pandemic of the 20th Century, and what its scale will be. Since it could break out at any moment, the world's 'flu experts are standing by permanently on "red alert". ■ 13 Diarrhoea! Diseases In developing countries, diarrhoeal diseases vie with acute respiratory infections as the leading cause of childhood mortality. Every year, up to 1,000 million diarrhoeal episodes cause four to five million deaths by Dhiman Barua an we really make much headway against diarrhoeal diseases today? This question is often asked because of the slow pace of improvement in socio-economic status, as well as water supplies and sanitation, wherever these diseases are a major public health problem. There is ample reason for concern. They are no longer a cause of anxiety in the industrialized countries, where such improvements have taken place. In the developing countries, however, these diseases vie with acute respiratory infections for the topmost place in the list of causes of childhood morbidity. Each year, every child aged under three in different areas of the developing world will suffer on the average between two and four episodes of diarrhoea. Diar- rhoea) diseases are also the single major killer of under fives, being responsible for one-third or more of all deaths in this age group. It is therefore not surprising to see the infant mortality rate in a coun- try fall as the death rate from this cause declines. Yet even children who survive are not always spared further suffering. Malnu- trition in children generally begins dur- ing diarrhoeal episodes, due to food withdrawal, loss of appetite, or malab- sorption. Often there is no time or op- portunity for the child to regain its origi- nal weight before another episode sets in. Again, undernourished children suffer more frequently and more severely, and thus the vicious cycle of diarrhoea- malnutrition-diarrhoea is established. In a careful community study, children have been found to spend about two months a year (16 per cent of the time) with diarrhoea, while in another study children spending more than five per cent of their days with diarrhoea have been found to falter in height and weight gain. Another side of the problem is that about one-third of the beds in children's hospitals or wards in endemic areas are usually occupied by diarrhoea patients receiving expensive intravenous fluids, antibiotics and other drugs (many of which are of doubtful value), thereby creating a heavy burden for the country's limited health budget. Unfortunately, deep-rooted cultural and behavioural factors have led people to accept episodes of diarrhoea as part of the normal process of growing up. They either believe that nothing can be done to prevent or cure diarrhoea, or they blindly follow harmful practices such as starving the child, to "rest the bowel". The complexity of the problem has so far prevented health authorities from coming to grips with it. However, the scientific community has profited enormously during the last 20 years from intensive research activities stimulated 14 primarily by the current seventh cholera pandemic. The flow of new knowledge on the etiological agents, the epidemiolo- gy, pathogenesis, pathophysiology, im- munology, and particularly the clinical management of diarrhoea, is unprece- dented. Treatment has been improved and simplified to such an extent that no more than one per cent of cases of cholera—the most severe of the acute diarrhoeal diseases—need die. Provided, therefore, that the people and the national health administrators have the will to apply the knowledge that is avail- able now, the answer to our question is an emphatic "yes" ; we can fight diarrhoeal diseases today. In most of the acute diarrhoeal dis- eases, death is due to dehydration. A simple method of oral rehydration has been developed that is safe and effective, and that can be delivered at home by village health workers (vHws) or by A breeding-ground for diarrhoeal diseases.. where waste-water is in contact with water used for drinking and washing. ( Photo WHO/UNICEF/S. K. Dutt) mothers with some guidance. The oral rehydration formulation (oRs) recom- mended by WHO contains 3.5 grams sodium chloride, 2.5 grams sodium bicar- bonate, 1.5 grams potassium chloride, and 20 grams glucose (or 40 grams of sucrose when glucose is not available or is too expensive) for one litre of drinking water. The availability of this single formula- tion for oral rehydration of all but the most severe cases of dehydration from acute diarrhoea in all ages, including newborn babies, offers immense advan- tages for national health services. The sodium concentration used in this formu- lation is essential for cholera and is help- ful for quick rehydration of children with other diarrhoeas. The safety and effec- tiveness of ORS have been demonstrated in numerous hospital-based and community studies. Usually one or two packets suf- fice, and vomiting does not appear to in- terfere seriously with oral rehydration if the mother persists with small repeated volumes. Children being rehydrated with ORS during diarrhoeal episodes also appear to eat better. Thus, diarrhoea-related malnutrition can be reduced if mothers are educated to continue feeding their children during and after the illness with appropriate, locally available foods. Delivery of this simple but scientifically sound treatment provides a good oppor- tunity to educate mothers, as they are then in a very receptive mood. They should be encouraged to continue breast- feeding and adopt appropriate weaning practices during and after the illness. Their acceptance and proper use of water 15 What help can be expected from WHO and other UN agencies? he Thirty-first World Health Assembly in 1978 agreed on the feasibility and the benefits of ' diarrhoeal disease" control pro- grammes and requested WHO to expand its activities in this field. The Organization therefore developed a Programme for Control of Diarrhoeal Diseases in which, with the support of other UN and national agencies, it is cooperating with national health authorities with the immediate aim of reducing diarrhoeal-related mortality and malnutrition while continuing to strive for a significant reduction in morbidity. Using the means already at hand, a significant impact can be made now, particularly on diarrhoeal- related mortality and malnutrition. With the forthcoming International Drinking Water Supply and Sanita- tion Decade, and the drive for Health for All by the Year 2000, the inter- national mood today offers a ripe opportunity for well-motivated national health administrators. The WHO Programme consists of a health services component and a research component, both of which contain a training element for national manpower development. It is guided by a Technical Advisory Group (TAG), which has identified as the most important strategies: appropriate clinical manage- ment, better maternal and child care practices, improved water supplies, sanitation and food hygiene, and epidemic control; health education is seen as an integral part of each strategy, for combating acute diarrhoeal diseases in the context of primary health care. Technical cooperation is available from the Organization at all stages of national programme planning, for- mulation, implementation (including training) and evaluation. In view of the importance of proper programme management, training courses for national programme managers and an operations manual have been developed. WHO is preparing man- uals and guidelines for the technical training of national health workers at different levels. UNDP is supporting a regional training programme in Asia. And from the outset UNICEF has been collaborating with WHO in the Pro- gramme by helping countries with ORS packets, establishing facilities for their local production, including relevant training to help countries become self-reliant. The Programme also supports epidemiological and operational re- search to identify the problems and determine the best means of apply- ing strategies and new knowledge, and basic research to improve and develop new tools for prevention, treatment and control, including drugs and vaccines. This component of the Programme is receiving strong support from UNDP and collabora- tion from the World Bank. Consider- able emphasis will be going into strengthening institutions, so as to enable them to undertake training and research in support of national programmes. A wide-ranging review of new scientific knowledge on acute diar- rhoeal diseases has been undertaken during the past two years by global scientific working groups, in which 64 scientists from 27 countries-19 of them developing and eight devel- oped—participated. These groups recommended research priorities that should be supported by the Pro- gramme, and their reports have been widely distributed. Similar multidisci- plinary groups convened by the WHO Regional Offices have been defining regional research priorities. The chain of collaborating centres and institutions now includes the International Centre for Diarrhoea! Disease Research in Dacca, Bangla- desh, and the National Institute of Cholera and Enteric Diseases in Cal- cutta, India, both of them designated as WHO collaborating centres for research and training. supply and sanitation facilities, and their understanding of the need for personal cleanliness and food hygiene for the family, can undoubtedly reduce the incidence of these diseases. A simple record-keeping system orga- nized by those who dispense the packets of ORS can make it possible to recognize the normal pattern of diarrhoeal diseases in the community and to detect promptly any changes in the age, severity, or seasonal distribution of cases which may herald the onset of an epidemic. This in turn enables appropriate control measures to be taken in time to prevent its spread. During the past two years, some 97 countries have expressed interest in developing a national programme for the control of diarrhoeal diseases, and about 70 of them are at various stages of pro- gramme planning and formulation. The majority are giving emphasis to oral re- hydration therapy in the initial stages, and 13 countries are at an advanced stage of planning for the national pro- duction of ORS packets or have already acquired automatic production plants, mainly with the help of UNICEF. A large number of countries have already adopted oral rehydration treat- ment, though sometimes without realiz- ing its full benefit. It is essential to make the necessary link between supplying ORS packets and training health workers in appropriate clinical management on the one hand, and, on the other, educating mothers in child care, nutrition and hygiene. Training activities may far out- strip the supply of ORS packets, or the packets may be distributed without suffi- cient training. Hospital-trained physi- cians, nurses and health auxiliaries may be slow to realize that, while intravenous rehydration is the appropriate treatment for severely dehydrated patients, oral rehydration has greater advantages for treating all other patients who are dehy- drated but who can drink. Training and logistics, which have been emphasized as important elements for assuring the success of diarrhoeal dis- ease control programmes, are at times wrongly viewed in isolation and conse- quently appear as a costly undertaking. The intended approach is to integrate the elements of diarrhoeal disease control into existing or developing programmes for primary health care. ORS produced or procured as an "essential drug" will be more easily financed, and savings in the cost of hospitalization, intravenous fluid, antibiotics and other drugs of doubtful value will help to pay for the ORS packets. In hospitals and health centres, the oral fluid can more economically be pre- pared in large volumes from ingredients in bulk containers. By these means, the need for packets can be minimised and programme costs substantially reduced. However, it is important to realize that there is a need for proper supervision of village health workers (vHws) and for a technical back-up facility to provide intravenous fluid therapy for cases of severe dehydration. For early treatment of diarrhoea in the home, some public health workers have recommended home-made brews using table salt and cane sugar measured by a "pinch and scoop" or a teaspoon. However, studies have shown that these 16 Above: A woman at a Philippines health centre learns how to prepare oral rehydration fluid for home treatment of her child. Below: Young infants or children with much vomiting are better rehydrated with small volumes of oral fluid given by spoon. ( Photos WHO/J. Abcede and WHO/ICDDR, Dacca) crude measures can give unacceptable variations in the concentration of the ingredients, usually on the high side, which can even be dangerous in the case of sodium. Several types of plastic, two-ended measuring spoons have been devised, which may be more accurate but require further evaluation. We need to know whether mothers do keep the spoons and use them during subsequent illnesses, as they are expected to. Moreover, it is by no means sure that salt and sugar are available in every kitchen; sugar, in par- ticular, can be a rather scarce commodity in some areas. WHO's Programme for Control of Diarrhoea) Diseases has set a global target of making oral rehydration thera- py accessible to 25 per cent of children below the age of five by the end of 1983. To back up this effort, the education of mothers in self-care—helped initially by the wiws—for very mild episodes of diarrhoea will remain an important ac- tivity. Self-care may consist of replacing diarrhoeal losses from the start by conti- nuing breastfeeding or, if the infant is not breastfed, giving weak tea, green coconut water, barley water, diluted rice water, or vegetable soup (made with car- rots or peas, for example) or plain water. However, mothers should also know that none of these is as good as ORS, and they should be taught to recognise any deteri- oration in the clinical state of the baby that calls urgently for ORS treatment. Although oral rehydration therapy is technically simple, providing it where it is most needed and applying it in the context of other related primary health care activities requires careful planning and continuous evaluation. Oral rehy- dration therapy can have an immediate impact on mortality and malnutrition, but will not in itself reduce morbidity. To do this, we must ensure the gradual im- plementation of all the recommended strategies, and the provision of oral rehy- dration offers an excellent opportunity for introducing them. The success of this programme is closely dependent on the development of national health services in the context of primary health care. It follows that the designation of a responsible person to coordinate diar- rhoeal disease control activities with related programmes of primary health care is essential for national pro- gramme development. ■ Polio- A Controllable Disease Even in well-immunized countries, sudden outbreaks of poliomyelitis show that importation of virulent wild polioviruses remain a threat. No nation can be safe except by maintaining high immunization levels by Joseph L. Melnick ,I. young child has a fever and is A fretful and restless. After a few days he seems to be improving— and then he awakes one morning with difficulty in breathing, or unable to walk. In some countries, medical students and young physicians alike may make special efforts to study even one such patient, as a medical rarity in their training. This child may be the only case of paralytic poliomyelitis that they will ever see. But in other parts of the world, such a patient is all too common a sight, and hundreds or even thousands of such attacks continue to occur. Why does paralytic polio still claim so many victims? Why is it being reported with increasing frequency in places that previously had noted no cases? Can it be halted? The lesson of smallpox eradica- tion is fresh with us. This was achieved through unprecedented co-operative ef- forts in global surveillance and immun- ization programmes. There is some rea- son to hope that success of this magni- tude might also be possible with polio- myelitis. Before we examine current prospects for controlling this crippling disease, it is useful to look back at some of our past experiences. Sporadic cases of paralytic poliomyelitis seem to have occurred for at least as long as mankind has had writ- ten history. An Egyptian stone carving from about 1500 B.C. depicts a priest with typical polio paralysis, and cases of paralysis occurring at an early age were known in Greco-Roman times. Sir Wal- ter Scott, born in 1771, wrote an auto- biographical account of his own illness that took place at about 18 months of age and left him permanently lame; the descriptions of the illness and residual paralysis are compatible with a diagnosis of poliomyelitis. The disease continued to be observed sporadically over the next century, usually referred to as a "debili- ty" occurring in young children. A major landmark in the efforts to learn more about poliomyelitis was von Heine's accurate description in 1840—a description that pointed to the spinal cord as the site of the fun- damental lesion that caused the paraly- sis. In the late 19th and early 20th centu- ries, the urban, industrialized parts of northern Europe and the United States began to suffer from epidemics of para- lytic polio that occurred with increasing frequency, size, and severity in more and more localities. Key observations were made on epidemics in Stockholm by O. Medin (1890) and in Vermont by C. S. Caverly (1894). These were followed by the important work of I. Wickman who—still without any knowledge of the causal agent of the disease analysed the large poliomyelitis epidemic of 1905 in Sweden, and docu- mented person-to-person transmission. All of the significant observations made of the disease, however, could not be advanced by experimental work in the laboratory until K. Landsteiner and H. Popper in 1909 were able to show that monkeys, after being injected with a bac- teria-free emulsion of spinal cord from a fatal human case, developed the typical paralytic disease with the very same damage to the spinal cord as that observed in humans. Soon thereafter, S. Flexner went further and transmitted the disease from one monkey to another. For another 40 years, polio resear- chers were obliged to conduct their ex- periments with live monkeys, since no other satisfactory laboratory animal was consistently susceptible. Under these conditions, it is remarkable how much was learned. Thus, the virus was regular- ly present in large amounts in stools of patients. Only rarely did a contact of a patient show evidence of the paralytic disease; nevertheless many such contacts also harboured the virus in their intesti- nal tracts and excreted large concentra- 18 Left: Routine early vaccination could have saved this Indonesian child from paralytic polio—and a lifetime's struggle with disablement. Above: The electron-microscope allows us to see the strange patterns of the poliovirus. ( Photos WHOI EPP L. Matlovski and WHOIJ.L. Melnick) tions of it in their stools. Some of these contacts had minor illnesses with fever, but most had no sickness whatsoever. They became known as healthy carriers of the virus. Chimpanzees and some spe- cies of monkeys could be infected not only by injection but also by feeding in- fectious material to them. Some of the infected animals developed paralysis when exposed to virus in the laboratory; others had an inapparent infection and were immunized by the treatment, as though they had been vaccinated. All the polioviruses that had been isolated could be differentiated into three antigenic types; this contributed greatly to under- standing and controlling poliomyelitis. Cell cultures from nerve tissue had been successfully prepared in 1907 by Harrison in the United States, and there followed some efforts to cultivate polio- viruses in such cultures, but there was no way of knowing whether the viruses mul- tiplied except by inoculating monkeys. In 1942 an important new dimension was added by a young Research Fellow from China, Huang Chen-hsiang, working at Columbia University in New York City. He showed that a neurotropic virus, western equine encephalitis virus, when cultivated in cultures prepared from minced muscle of chick embryos, pro- duced characteristic, microscopically ob- servable cell damage. By measuring these effects of the virus on the cells, Huang was able to calculate the quantities of virus present in the culture, and also to test serum for the presence of antibodies against the virus. In addition, he devel- oped a virus test based on colour changes in the culture fluid that could be ob- served with the naked eye. Both of these discoveries foresha- dowed by several years the work of oth- ers that became much better recognized in the development of virology. At the time, the significance of Huang's dis- coveries may have been missed, partly because he soon returned to his native China and did not pursue his findings. He has, however, remained active and productive in China's biomedical com- munity, and is at present a Professor and Co-Director of the Institute of Virology, the Chinese Academy of Medical Sciences, in Beijing. In 1950, J. F. Enders, T. H. Weller, and F. C. Robbins demonstrated that polio- virus could be grown with visible cell damage in cultures of primate cells derived from tissues other than those of the nervous system. The important work of these investigators was recognized by the award of the Nobel Prize in 1954. With cell cultures, relatively simple and rapid tests were soon devised to detect the polioviruses, to measure them quan- titatively and also to determine the levels of antibodies that developed after infec- tion. Using these tests, we were able to purify the virus and visualize it in the electron-microscope. Now investigators could begin to analyse the biochemical and biophysical characteristics of the polioviruses, trace the details of their multiplication, and explore the mechanisms by which they produce their damage to individual cells and to the infected human being. Most importantly, this new technology led to the ability to produce the huge quantities of standardized poliovirus stocks that were required for preparation of killed vaccines. Furthermore, it opened the way to live poliovirus vaccines, based on the possibility that poliovirus strains, by propagation under specified conditions through many generations in cells widely different from human spinal cord cells, could be deliberately attenuated or weakened so as to become no longer neu- rovirulent for man; that is to say, the vaccine virus, even though alive, could no longer invade the human brain or spinal cord. Two excellent vaccines were developed 19 Polio A Controllable Disease Left : This Egyptian stone carving dating from about 1500 B.C. depicts a priest with typical polio paralysis. One day we may be able to conquer this disease that has crippled so many people over the centuries. ( Photo WHO/J.L. Melnick) Right : Even in well-immunized countries, "almost complete control" still represents an important gap in protection against poliomyelitis. A little Danish boy wrestles with leg-braces which he may need all his life. ( Photo WHO/E. Schwab) almost simultaneously: a killed-virus vaccine administered by injection, and a live, attenuated virus vaccine, adminis- tered orally. These products are often referred to as the Salk and Sabin vac- cines, after the investigators J. E. Salk and A. B. Sabin who played leading roles in their development. However, it was the dedicated and brilliant efforts of many workers in widely scattered labo- ratories which in a very short period brought forth the vaccines and demon- strated their safety and usefulness—a demonstration confirmed for both the live and the killed poliovirus vaccines by the record of the past 25 years. In many developed countries with ade- quately financed public health services, poliomyelitis has been brought under al- most complete control. The decrease in poliomyelitis cases is graphically illus- trated in the United States. In 1951-55, shortly before the killed poliovaccine became generally available, the average annual number of paralytic poliomyelitis cases was about 21,000. The wide use of killed virus vaccine brought a marked reduction, to about 2,500 each year. Af- ter the live poliovirus vaccine was intro- duced in 1962-63, the number of cases decreased dramatically, to 17 in 1971, and to less than 10 in 1974. It has remained low ever since. The United States now relies almost completely on live poliovaccine, and it appears that there is no longer any endogenous reser- voir of wild polioviruses within the coun- try. Wild strains continue to be intro- duced, particularly from Mexico, but even such imported cases are sporadic and almost never result in secondary cases. It has been postulated that the use of live poliovaccine has achieved this result by establishing intestinal resistance extensively within the population, reduc- ing the pool of susceptible individuals below the level that would permit the wild polioviruses to continue being circu- lated and thus perpetuated. Even in the well-immunized countries, however, "almost complete control" represents an important gap in protec- tion against poliomyelitis. This vulner- ability was shown most recently by out- breaks among members of sects refusing vaccine on religious grounds in the Netherlands, Canada, and the United States. Although the virus strain was an imported one, and although it did not spread beyond the particular unimmu- nized group into the larger community in any of the countries involved, the out- breaks were an unfortunate reminder that virulent wild polioviruses do indeed still exist and move freely in the world. Thus importation of virulent wild polio- viruses remains a clear danger against which no nation can be secure except by maintaining high immunization levels. In some developing countries, deter- mined immunization efforts are already bringing progress against poliomyelitis. But there are more than 70 countries in which poliomyelitis has not been brought under control. These are mostly countries in tropical or subtropical cli- mates, where the incidence of paralytic poliomyelitis had been previously believed to be very low. Recent surveys of lameness in school-age children have provided important insights into the prevalence of types of lameness compa- tible with residual paralysis following poliomyelitis. Such surveys of lameness, however, are not required for ferreting out cases of polio, since large and ob- vious epidemics are now occurring in many developing countries. In a total population of almost 2,000 million per- sons in those countries where the disease has not yet been controlled, tens of thou- sands of cases are being reported each year, and doubtless many more go unre- ported. We must face the fact that polio- myelitis is an important health hazard to children in any part of the world where immunization is not being fully and effectively used. In many areas, the burden of poverty 20 2t,- 4. -"V-ireSV.C•C:rrf*k Ii1MVA-VaO‘'Z,10.i. 'Clit-410K-44A,17 and disease is so great and the support for health services so limited that control of poliomyelitis seems still only a distant goal, unless significant changes are made in the national public health pro- grammes With this in mind, the WHO Expanded Programme on Immunization was recently initiated with the objective of reducing sickness and deaths from six target diseases, one of them being polio- myelitis, by providing immunization against them for every child in the world by 1990. The Programme activities depend heavily upon technical co-opera- tion among all countries, with emphasis on the developing countries. A large number of nations are now on record as actively participating. Developing countries in tropical regions not only face economic and logistic problems in providing sufficient doses of vaccine to a large proportion of the infants and young children. In some of these countries—where the lower cost and greater ease of administering live vaccines would be important advan- tages—live vaccines have not induced antibody production in a satisfactorily high percentage of vaccinees. This lower rate of vaccine "takes" has been ascribed to various factors such as interference from other enteroviruses already present in the intestinal tract, the presence of an- tibody in breast milk, the presence of cel- lular resistance in the intestinal tract due to previous exposure to wild polioviruses (or perhaps to related viruses), and the presence of an inhibitor in the alimentary tract (saliva) of infants which acts against multiplication of the vaccine virus. Some feel that this low response, regardless of the reason, can be over- come by proper and continuing use of live vaccine. But the situation may be ag- gravated by the fact that the time for a newborn infant to acquire protective im- munity in such areas is short, because in some places poliomyelitis may attack children in their first months of life, and almost all poliomyelitis cases occur within the first two years. Given the determination evidenced by countries participating in the Expanded Programme on Immunization to provide immunization services for all children in the world, the prospects for eliminating poliomyelitis as a public health problem appear good. But the experiences being documented in developing countries in tropical regions, where the bulk of polio- myelitis is now occurring, also suggest that further work is required to deter- mine the most cost-effective immuniza- tion strategy, taking into account the relative merits and the relative costs of the live and killed polio vaccines. The impact of these vaccines in reduc- ing the incidence of disease must be assessed in community-based studies in developing countries, since it cannot be predicted accurately from studies of the antibody responses in immunized indi- viduals, nor from experiences in devel- oped countries with temperate climates. An immunization strategy employed recently in specific areas of the Eastern Mediterranean suggested that the use of both of these vaccines together might offer advantages. Further studies of this, as well as further studies into the impact of the live and killed vaccine alone, are needed, and it is hoped they will be carried out in the near future. All the indications are that, with such combinations of killed and live polio- vaccines, we now have the appropriate tools—and the knowledge—to be able to establish impregnable barriers to wild polioviruses so that, once they die out in an area, there would be no available sus- ceptible persons to allow imported viruses to gain a new foothold. With cor- rect deployment of available vaccines, it should be possible finally to eliminate poliomyelitis from the world, and to bring about the total eradication of the virulent polioviruses that have crippled countless thousands of human beings over many centuries. • 21 The Health Education Council Sexually Transmitted Diseases Health education can help to encourage more open attitudes towards sexually transmitted diseases, so that people learn to seek prompt health care when they notice danger symptoms or if they are at risk by Donald Gould lir( enicillin can cure a majority of ° the victims of gonorrhoea within hours, and most sufferers from syphilis within days. Yet the sex- ually transmitted, or venereal, diseases are on the increase, and it has been calculated that four times every second somebody, somewhere in the world, is contracting one of the major infections. These infections have been well termed "social diseases". Originally the descrip- tion was used as a euphemism, and in or- der to avoid a more direct and embar- rassing label, but it is peculiarly apt. We know how to avoid them, and for most cases that do occur a quick and sure remedy is available. But despite such favourable circumstances, attempts to reduce the incidence of the sexually transmitted diseases (sTD) have failed dismally, and this is because modern atti- tudes towards sex, and our modern way of life, including a dramatic increase in personal mobility and travel (that is to say, social factors), have worked more powerfully in favour of the spread of such diseases than modern medicines and understandings have worked for their containment. The term "venereal disease" is a blan- ket label used to describe a wide variety of totally different afflictions, caused by an equally motley collection of infecting organisms. The one thing which most of the responsible agents have in common is a fragility which makes it impossible for them to survive more than very briefly outside the (for them) ideal conditions provided by the human body. They can- Are education and propaganda sufficient to alter the habits which breed sexually trans- mitted diseases? (Photo WHO/Camera Press, London) not tolerate, for example, drying, or sig- nificant temperature changes, or similar adverse circumstances. In this respect they differ strongly from, say, the cholera vibrio which lives happily in water, or the many other organisms which survive in soil and food and so on, so that they can pass between people who have never met, and may, indeed, live half a world apart. By contrast, the organisms causing the major infections (including syphilis and gonorrhoea) can only pass from one per- son to another during a period of close physical contact. Moreover, this contact usually has to be between warm, moist surfaces, so that the organisms are pro- tected from the rapidly lethal effects of cooling and drying during their migra- tion into the body of a new victim. Very few human activities provide this kind of contact between two people. One is the act of making love. Another (where the two concerned are mother and child) is pregnancy and childbirth. That is why the venereal diseases form a special category of infections, and why they are named after Venus, the goddess of love. The responsible germs have no partic- ular affinity for the organs of reproduc- tion. They attack the penis, the vulva and vagina, the urethra and the egg tubes most commonly, simply because these structures happen to be at or near the point at which the organisms gain entry to the body. But, given the opportunity, venereal germs will take up residence in other issues. Gonococcal infections of the throat and rectum, for example, which can follow oral sex and sodomy, are becoming diagnosed with increasing frequency, partly through improved diagnostic methods but perhaps also because these practices are becoming more widespread and because doctors are now alert to the possibility of gonococci gaining a foothold in less usual locations. The non-specific nature of the major sexually transmitted infections is also shown by the fact that in the later stages of untreated syphilis or gonorrhoea, when the germs have had the opportuni- ty to enter the bloodstream, all kinds of tissues may become involved. Gonococ- ci, for example, can, inter alia, cause acute arthritis, or attack the skin or the outer lining membrane of the heart. Tre- ponema pallidum, the germ of syphilis, will settle in and damage almost any organ in the body, which is why, before the advent of penicillin, it was one of the major killing diseases in the Western world. This is in sharp contrast to the choosiness shown by many other organ- isms dangerous to mankind, some of which will only thrive in one kind of cell. (An example is the rabies virus which only attacks nerve cells in the brain.) Not the only culprits Whilst syphilis and gonorrhoea are the two major sexually transmitted infec- tions, both in terms of their prevalence and the damage they can do, they are by no means the only ones. Ulcers on the genitals, often accompanied by swollen regional glands, are characteristic of three conditions, apart from the so- called "primary sore" of syphilis. These are chancroid or "soft sore" (the syphi- litic sore is characteristically hard), lym- phogranuloma venereum of "climatic bubo", and granuloma inguinale. They are common in the tropics and subtrop- ics and their spread is encouraged by poor hygiene. Non-specific urethritis is the term given to a non-gonococcal inflammation 23 L1H i emphasises three I strategies in trying to il: reduce the spread of these diseases. Health education—sex education—is an essential first step. Every schoolboy and every schoolgirl should learn the facts of love before they start experimenting. This education effort should take into account the kind of behaviour that contributes to the problem, people's attitudes towards control measures, and effective ways of altering social behaviour. This will re- quire the cooperation of individuals, community leaders and governmental and non-governmental agencies. Health education is also essential for program- mes designed to reduce the conse- quences of infection—particularly the consequences of prolonged infection in women. People have to learn to seek prompt health care when they notice the symptoms or if they are at risk, and should be motivated towards ensuring the same care for their sex partners. The second strategy is directed at the control of these diseases by two spe- cific approaches, which are complemen- tary and could work like a double break. Primary prevention would limit trans- mission of the disease by altering sexual behaviour, and would also decrease transmission through the use of pro- phylactic methods including the appli- cation of specific vaccines which are now being developed. Once infection has occurred, secondary prevention would limit the development of compli- cations and further transmission by ensuring that patients and their infected partners have access to and avail them- selves of effective treatment early in the course of the disease. The third strategy is to break away from the concept that the diagnosis and treatment of these diseases are the priv- ilege of a few specialized clinics. All levels of the health care service should be involved in STD control in order to provide all population groups with access to treatment. Recent experiences in developing countries have proved the value of simplified approaches to con- trolling these diseases. Auxiliary health workers were able after only limited training to separate patients into high- risk and low-risk groups. They were then able to provide treatment to all patients at high risk and to their sexual partners. In one country, this approach produced a substantial decrease in the incidence of disease, and was readily accepted by the community and the health person- nel. Further testing is continuing; but this success does suggest that some control of sexually transmitted diseases is feasible even in areas where the health units do not yet have access to laboratory technology for diagnosis. of the male urethra, often involving the prostate gland and the seminal vesicles, and accompanied by a discharge and perhaps painful urination. It is normally the result of sexual contact, and may be caused by a number of different organ- isms. Trichomoniasis, which produces ir- ritation and a white discharge from the vagina in women, is caused by a proto- zoon (a microscopic organism somewhat more complex than a bacterium); sexual contact is the major means of transmis- sion. Pregnant women are particularly susceptible. Obviously, any infection which can travel directly from one person to another may be transmitted during the close communion of sex, but scabies and pubic lice ("crabs") have earned a special reputation for their ten- dency to use the sex act as an opportuni- ty for changing hosts. The many different etiologic agents can also cause a wide range of disorders including infertility and abortion, salpin- gitis, epididymitis, vulvitis, vaginitis, cer- vicitis, female urethritis, proctitis and acute arthritis with genital infection. And among congenital and perinatal in- fections that may affect small children are pneumonia (caused by C. trachoma- tis), otitis media (C. trachomatis), neu- romental impairment (Cytomegalovirus, Herpes simplex virus, T. pallidum), eye infection (C. trachomatis, N. gonorr- hoea) and sepsis—which can even prove fatal (Group B beta hemolytic strepto- coccus, Herpes virus simplex). Finally there are a number of condi- tions not normally regarded as venereal diseases at all in which sexual intercourse appears to play a role. Cancer of the cer- vix (the neck of the womb), for example, virtually never develops in nuns, but occurs most frequently in women who have experienced an active sex life which began at an early age, particularly when many different men have been involved. The virus which causes hepatitis-B (transfusion jaundice) is sometimes pre- sent in the semen of infected men, and this would explain the finding from epi- demiological studies that the disease can be sexually transmitted. It is probable that in the course of time more diseases will be added to the list of afflictions which can, on occasion, be spread by the special contacts and exchange of body fluids which take place when two people make love. Of the two principal contagions, gonorrhoea is by far the commoner, oc- curring (according to the country) ten to fifty times more frequently than syphilis, and in Britain now, for example, there is less syphilis than there was just after World War II. But this can be small cause for satisfaction in view of the fact that in the world at large well over three million new syphilitic infections occur each year. And taking syphilis and gonorrhoea together, sexually trans- mitted disease is showing an alarming increase everywhere. This breakdown in the control of these infections (for that is what it amounts to) came as an unpleasant shock to the health authorities, because not many years ago there was a general assumption that new methods of treatment would lead to the rapid reduction, if not the dis- appearance, of the two most widespread and damaging of the sicknesses spread by the exercise of one of mankind's most powerful and basic instincts. With the advent of penicillin, syphilis and gonorrhoea were among the pre- viously obstinate and dangerous infec- tions which suddenly became readily treatable. The antibiotic clears up the majority of cases of gonorrhoea after a single injection, and the availability of some antibiotics pills allows many patients to avoid even the trivial discom- fort of a needle prick. Syphilis can usual- ly be cured by a ten-day course of peni- cillin, and there are other antibiotics for those few patients who are sensitive to the drug. WHO played a major role in popularis- ing antibiotic therapy for these diseases throughout the world, and also tackled the problem of the 200 million or so people in tropical countries suffering from yaws and pinta, which are penicillin- sensitive infections caused by a germ very similar to that producing syphilis, but which are spread by personal contact not involving sexual activity. In the first ten years after World War II, WHO was responsible for distri- buting ten million dollars-worth of peni- cillin for the so-called treponemal dis- eases, and the campaign was an out- standing success. The administration of the drug to contacts, as well as to infect- ed people, reduced the incidence of these diseases in affected communities from an appalling 20 per cent to less than one per cent : it has even been eradicated in some countries. A similarly drastic reduction in the sex- ually transmitted diseases was achieved in the industrialized countries. In 1945 a senior consultant venereologist at a Lon- don teaching hospital described England as "a general brothel". The war had dis- rupted families, and had produced a whole generation of young people who had been uprooted from their homes and jobs, who were being moved around the Sexually Transmitted Diseases Every schoolboy and every schoolgirl should learn the facts of love before they start ex- perimenting in the field: sex education is at least one of the keys to the problem of "social diseases". ( Photo WHO/E. Mandelmann) world, and who often had good reason to feel that each day might be their last. There was an inevitable and enormous increase in promiscuity, which is far and away the most powerful ally of the germs which cause these infections. The result of all this was that 45,000 cases of gonorrhoea occurred in Britain in 1945, but then the numbers went down, so that five years later there were only 17,000 new cases. Antibiotics must have played an important part in bringing about this great improvement, for whereas an untreated victim of gonorrhoea can continue to spread the disease for months or years, a treated patient is generally safe within a couple of weeks. But then the picture changed, and by the mid-fifties the graph of these infections in Britain and elsewhere had begun to take an upward swing, and this has continued ever since. Over the past quarter-century, gonorrhoea among males has increased by over 200 per cent, and among women the increase has been 500 per cent. Most disturbingly there has been a threefold rise in the proportion of infected girls who are still in their teens, so that they now account for over one- third of the total. A particularly unhappy aspect of this spread of gonorrhoea is the effect it has upon women. There has been a great in- crease in the incidence of gonococcal sal- pingitis. This is an inflammation of the egg tubes which lead from the ovaries to the womb. The inflammation is followed by scarring, so that the tubes become blocked. When this happens, pregnancy is impossible, so that a teenage indiscre- tion can lead to sterility. Women are particularly vulnerable to this and other serious complications of the disease because they are often unaware of the fact that they have been infected. When a man gets gonorrhoea he usually develops fairly obvious symp- toms and signs. There is a discharge of pus-like material from the penis, and this is usually accompanied by some pain or discomfort on passing urine; these symp- toms show themselves within days of the infection being contracted. For a women the situation is entirely different. She may have no symptoms at all, and when they do occur they are usually slight. So she doesn't seek treatment, but this dis- ease can be transmitted to her child even though she shows no symptoms. Similar- ly the painless primary sore of syphilis is obvious when it develops on a man's penis, but may not be noticed on a women's vulva. Since modern treatment for syphilis and gonorrhoea and some other sexually transmitted diseases is so effective and is so freely available, why is it that these diseases have not become a plague of the past, together with such previously common and destructive infections as pneumonia and tuberculosis? Undoubtedly a sharp increase in pro- miscuity must be a major cause, allied to a general ignorance of the nature of these plagues and the manner of their spread— an ignorance fostered by the assumption that such afflictions are peculiar to rogues and vagabonds and loose women, and that the subject need not concern the "decent" members of society. The facts contradict this assumption. In Britain only some five per cent of sexually trans- mitted diseases is traceable to prosti- tutes. They know their job too well to court disaster by "obliging" obviously infected men, and they are also keenly aware of the signs and symptoms which call for treatment. So we are left with the conclusion that education must be the key to the prob- lem. But would it be enough if every schoolboy and every schoolgirl learned, as they should, the facts of love, before they started experimenting? Experience with vigorous attempts to dissuade peo- ple from killing themselves by smoking suggests that education and propaganda alone will not be enough to alter the habits which breed sexually transmitted diseases. People will do what pleases them, regardless of the most painful possible consequences. One hope for the future is that vaccines will become available to protect people against gonorrhoea and syphilis just as children are now routinely protected against diphtheria and poliomyelitis. ■ 25 uring the past 40 years steady progress has been made in culti- vating viruses from the respirato- ry secretions of persons suffering from acute respiratory disease. As a result the relationship between virus causes and clinical illnesses has been studied in many different countries with, on the whole, remarkable agreement. Though the viruses and certain bacteria are held to account for most of the acute respiratory illnesses, the clinicians can distinguish relatively few syndromes one from another, considering the enormous number of different viruses that exist. The process of defining virus causes of human respiratory disease began in the laboratory in the early 1930s, when the first strains of influenza virus were recovered, and it was expanded in 1940 with the isolation of similar yet distinct viruses known as influenza B to dis- tinguish them from the first known influenza A. With the introduction of the tissue cul- ture method of cultivation in the 1950s, successive groups of other viruses were recovered, first of all the adenoviruses, then the parainfluenza and respiratory syncytial (Rs) viruses. But still the com- monest of all respiratory illnesses—the common cold—failed to yield a causative agent in spite of proof of transmission of infection in volunteers. In the 1960s, newer methods of cultivation yielded the first strains of the rhinovirus group, and this was soon enlarged to its present size of over 100 different serotypes. The last of the respiratory viruses—the corona- viruses—were revealed by the electron- microscope. The enteroviruses had meanwhile shown that they could cause respiratory symptoms, though less often than other effects, and these completed the list of seven known respiratory virus groups— the common cold, influenza, feverish sore throat, croup, bronchitis, bronchio- litis and pneumonia. The fact that these viruses possess multiple serotypes which are immunologically distinct and exhibit little or no cross-protection is one reason for the difficulty in developing specific vaccines. In addition, the superficial nature of their infection in the epithelium of the upper respiratory passages, the trachea and bronchi results in a failure to produce a long-lasting immunity, so that infection often recurs. This article cannot for lack of space deal with specific respiratory illnesses of bacterial origin, such as whooping cough, diphtheria or scarlet fever. The acute respiratory illnesses are, however, responsible for an enormous toll of disease affecting all members of the community. Although each virus group can at times cause each syndrome, the majority of illnesses caused by each group belongs to one or more syndromes. Even so, the problem of clinical differentiation is dif- ficult and requires laboratory help to provide evidence of causation. This, in the absence of specific therapy, is a rela- tively unrewarding task though useful epidemiologically. The following brief account is based on diagnostic criteria useful in carrying out combined labora- tory and clinical studies. Common cold Personal experience of colds indicates the familiar pattern of sneezing, dry throat, discharging nose (coryza) and cough. Children are often febrile for brief periods but adult colds are general- ly without fever. Otitis media is a not uncommon complication in children, due to bacterial infection. It is recog- nized by earache, deafness and, if neglected, discharging ears. Bronchitis is often due to viral spread down the lower respiratory tract and is not responsive in its early stage to antibacterial chemo- therapy. Rhinoviruses and coronaviruses are the chief causes of the common cold syndrome. Influenza Sudden onset of headache, shiveriness, dry cough and illness. Fever lasts from Acute Respiratory Diseases At present, immunization is the only control method available against the acute respiratory diseases; the need today is for science to discover safe, broadly-active antiviral compounds by Sir Charles Stuart-Harris 26 How a sneeze may spread infection—and how simple use of a handkerchief can trap the potentially infectious aerosol droplets. (Photo WHO/C. Stuart-Harris) one to five days, averaging two days in adults but lasting longer in children. A blocked nose, slight sore throat, produc- tive cough, hoarse voice and muscle pains complete the symptomatology. Feverish illness resembling the influenza virus infection, but not so caused, occurs outside the period of prevalence of these viruses, and may be due to any of the other viruses but principally adeno- viruses, coronaviruses or some entero- viruses. Feverish sore throat (tonsillitis or pharyngitis) The syndrome can be caused by ade- novirus infection, particularly in children and young adults, with outbreaks in schools, camps and military establish- ments. However, for tonsillitis, the main causative agents are bacteria; the haemo- lytic streptococcus of group A variety is now known to cause about 40 per cent of cases of this syndrome, which is common in school-age children. Croup and laryngotracheitis Hoarse voice, croaky cough and noisy breathing (stridor), commonly due to parainfluenza viruses in infants and chil- dren aged under five. Older children may suffer from obstructive laryngitis due to influenza virus. Bronchitis Cough, wheezing, breathlessness and fever. Accompanying signs in the chest and perhaps recession of the intercostal spaces from airways obstruction. Any of the respiratory viruses may cause this syndrome. Bronchiolitis Rapid respiration in children aged un- der two, blueness of the lips and relative silence over the distended chest make this syndrome difficult to miss, but pneu- monia may be suspected. RS virus is chiefly concerned. Pneumonia The many varieties of pneumonia are characterized by sharp pleural pain on inspiration, with dry cough later becom- ing productive and accompanied by signs in the chest of consolidation of the lungs. There may be a high fatality rate, partic- ularly during influenza epidemics. An important clinical observation made in 1965 is that pneumonia developing synchronically with influenza may be of bacterial origin—either pneumococcal or staphylococcal and either lobar or patchy in distribution. But pneumonia with onset several days after the influenza attack is nearly always pneumococcal and usually lobar in distribution. Although pneumonia is largely bac- terial in origin, in some instances of in- fluenzal pneumonia it has been shown that in a minority of "early" fatal cases there was virus in the lung and no bac- terial pathogen could be isolated; at the same time, characteristic histological changes that occurred in the lung were associated with what has been termed "influenza-virus" pneumonia. A number of fatal "influenza-virus" pneumonia infections can occur in patients with chronic cardiac or respiratory diseases, in those who are pregnant or in infants. Atypical pneumonia due to mycoplas- ma causes little pain in the chest but spreads slowly through families unlike the other bacterial pneumonias. The newly discovered bacillus of Legion- naire's disease causes a relatively se- vere, sometimes fatal, pneumonia in outbreaks among adults exposed to a common source of infection in hotels or hospitals. Seasonal effects From a nadir in mid-summer, the prevalence of total acute respiratory dis- eases rises to a peak approximately four to six times higher during the winter. This is the experience in the Northern 27 hemisphere, and though climate and sea- sons differ from country to country there is a similar effect of season on illness throughout the world. Experience in tropical climates with a pronounced wet and dry season indicate that respiratory infections rise in prevalence at the onset of the rainy season. There is no clear evidence why acute respiratory infections exhibit this sea- sonal effect. Of course, people change their habits during the winter, with great- er crowding together in ill-ventilated rooms and closer personal contact. Such changes may improve the communi- cability of airborne infection. From the point of view of the viruses, humidity seems to be of greater importance than environmental temperature. Relatively fragile viruses such as influenza and RS do not survive long outside the host. In hot dry climates, desiccation probably increases the rate of decay of virus- containing droplets that are responsible for transmission from the nose and throat of infected persons. A large quantity of such droplets are expelled every time a sufferer sneezes. The finest aerosol drop- lets remain suspended in the air much longer when the relative humidity is high during cold damp weather. So it Remote handling of influenza virus cultures in an ultra-violet chamber ensures that there is no contamination. Right: A railway commuter in Japan uses a face-mask as a logical safeguard against transmission of respiratory diseases. (Photos WHO and WHO/P. Almasy) is probably the improvement of trans- mission of infection which encourages respiratory infections in winter-time. Limiting transmission through the use of disposable handkerchiefs or masks is certainly a logical precaution. A week-by-week chart of the commu- nity incidence of acute respiratory infec- tions shows a series of fluctuations. These are now known to be the result of minor outbreaks, frequently localized or confined to a few families, the neigh- bourhood of a school or a play-centre; cases occur mostly in infants and chil- dren, but the infection can spread to parents. Each outbreak represents infec- tion by a different virus group, or even a different serotype of the same virus. Some viruses, such as influenza, spread for a few weeks only and then dis- appear; others such as rhinoviruses recur constantly, yet one serotype may persist for only a short time and then be succeeded by another. Although susceptibility to each of the groups of viruses is present throughout life, there is a decrease with age in the relative likelihood of infection by all groups. Thus the maximum age-inci- dence of influenza A and B—with illness sufficient to warrant medical care—is stated to be from five to fifteen years of age. The existence of influenza virus in- fection in infants and pre-school chil- dren, however, is often missed unless routine tests of nasopharyngeal secre- tions are carried out, and then the at- tack-rate may be found to be even higher than that in schoolchildren. In the aged or adults with chronic lung or heart dis- ease, influenza infection is certainly less common than in children but its effects are more serious and can even be fatal. Other viral respiratory infections are mainly seen in children, although of course common cold viruses equally affect adults. Preventive measures Because of the paucity of antiviral agents with prophylactic or curative properties, immunization is the only control method available at present. Unfortunately immunization is pos- sible against relatively few viruses and, in general, it is less effective than that against systemic diseases such as measles or rubella. Specific measures of prevention are not developing as fast as might have been anticipated. The respiratory diseases and their causative viruses are now known. The multiplicity of viruses is discourag- ing from the standpoint of immuniza- tion, and at the same time antiviral therapy with drugs is only effective in one or two instances. Amantadine exerts as good a prophylactic effect on influen- za A as inactivated vaccine, but for it to work as a preventive requires its use for six or more weeks, and it has no effect on influenza B. Ribavirin is active against both influenza A and B viruses, but has undesirable toxic effects. The need is for safe, broadly-active antiviral compounds, and this brings the question of interferon to the fore. Inter- feron is a natural product produced by the human cell in response to viral infec- tions. Its potential is great because of its broad spectrum and relative lack of tox- icity. This substance is currently causing a great stir in the scientific world because of the recent breakthrough in its produc- tion, using gene-splicing techniques and persuading common bacteria (E. coli) to produce it. Mankind may yet find the ultimate weapon against the acute respiratory diseases. ■ 28 44: Health worker places ice packs in vaccine cold box. Photo WHO New Products Ensure Vaccine Safety in Tropical Climates A number of new products developed in projects sup- ported by WHO, UNICEF and some bilateral aid agencies are beginning to answer the vexed question of the storage and transportation of vaccine in tropical climates—a matter of crucial importance for the success of the Expanded Programme on Immunization (EPI). The programme aims to reduce the heavy mortality among children in the de- veloping countries caused by six diseases—diphtheria, whooping cough, tetanus, poliomyelitis, measles and tuberculosis—against all of which effective vaccines ex- ist. However, since vaccines are among the most delicate of biological products, the big challenge faced by the coun- tries in developing their EPI programmes was: how to safely store and transport the large quantities of vaccines required in hot tropical cli- mates, particularly in areas with poor refrigeration facili- ties and lacking a regular or any electricity supply. A great deal of research and thought has been spent on setting up "cold chains" to ensure that a vaccine re- tains its potency during the time that must necessarily elapse between its issue from the laboratory and arrival at the consumer's door in his re- mote rural village, often cut off from all modern means of tra nsport. Products developed re- cently hold out the promise that the problem is perhaps not as stubborn as it had orig- inally seemed. For example, a refrigerator put into use re- cently keeps vaccines at a safe temperature even in the event of lengthy power cuts. All it needs is a supply of electricity for eight hours a day to keep vaccines at a temperature below 8° C (47° F). Also in use are large cold boxes that require no power supply and can keep vaccines cold for periods of up to one week. Newly de- vised vaccine carriers, small enough to be carried by primary health care workers on their vaccination rounds, can keep vaccines at a safe temperature for three days. One of the strongest links of the "cold chain", of course, are the people who use and maintain the equipment. An important part of the EPI pro- gramme, therefore, is training courses for various levels of health workers in the man- agement of the chain and maintenance of the equip- ment. A number of publica- tions describing the new pro- ducts as well as guides and manuals for people who look after and handle vaccines are available free of charge from WHO headquarters and re- gional offices. Among these is an annotated bibliogra- phy of over 30 cold chain papers including technical reports, slide shows, films, a cold chain game, posters and stickers. Mouth pipetting: a dangerous practice The above photograph, which appeared on this page last June, has brought us many readers' protests for publishing it without com- ment. We are glad to take this opportunity to draw attention to the serious hazards of mouth pipetting which good laboratory practice forbids everywhere but which is by no means obsolete. Pipettes are basic scientific equipment used throughout the world for volumetric mea- surement of fluids and for their transfer from one con- tainer to another. Since the fluids frequently contain in- fectious, toxic, corrosive or radioactive agents, the im- proper use of the pipettes can do serious harm to persons handling them. The pipette becomes a specially danger- ous piece of equipment when pipetting involves suction by mouth. It is estimated that more than 13 per cent of all known laboratory accidents that resulted in infection were caused by oral aspiration through a 'pipette. Photo WHO/T. Farkas A dangerous practice. Laboratory acquired infec- tions due to mouth pipetting include typhoid fever, salm- onellosis, schigellosis, tula- remia, scarlet fever, hepatitis, influenza and coxsackie virus infection. Why laboratory scientists, whose very training should impel them to do otherwise, should put mouth to pipette defies understanding. A Brit- ish writer, C. Collins, himself a laboratory scientist, speaks of a widely prevalent "It can't happen to me" syndrome. Some laboratory workers feel they have a better control when using suction by mouth 000 000 000 000 000 000 000 000 000 000 000000 00* 00. 1114141100• so. 666::: 0000 0 **emu 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000000 000 000 000 000 000 OOOOOO 000 000 00. 0011 00000* 000 1100 000 000 000 000 000 000 000 000 000 30 Photo WHO/T. Farkas Inter-departmental meeting discusses malaria strategy. Authors of the month Dr Albert ZAHRA is Director of the Division of Communicable Diseases at WHO headquarters in Geneva. Dr P.L. BRES is Chief of the Virus Diseases unit in the same Divi- sion, wit°, Geneva. Mrs Martine ALLAIN-REGNAULT is Medical Correspondent for the French television station, Antenne 2. Dr Dhiman BARUA is Chief of the Diarrhoeal Diseases Control Programme at wHo headquar- ters, Geneva. Professor Joseph L. MELNICK is Professor of Virology and Epi- demiology at the Baylor College of Medicine, Houston, Texas, USA, and Director of the WHO Collaborating Centre for Virus Reference and Research, Houston. Dr Donald GOULD is a medical journalist who contributes regu- larly to a number of specialist and non-specialist publications. Sir Charles STUART-HARRIS is Professor of Medicine in the De- partment of Virology at the Uni- versity of Sheffield Medical School, UK . In the next issue The December issue of World Health will have no single theme. Articles in this issue will range over a wide variety of topics, including Cuba's revolution in health care, hospitals as potential breeding-grounds for in- fectious diseases, and the 30th anniversary of the United Nations Relief and Works Agency for Palestine Refugees in the Near East (UNRWA). than rubber bulbs or other mechanical equipment. In some cases, perhaps, famil- iarity breeds contempt, and caution is ignored. WHO's position with re- gard to this practice is clear: mouth pipetting should be forbidden in all laboratories, according to the Minimum Standards of Laboratory Safety (1979). The WHO/ CDC training manual, Labora- tory Techniques for the De- tection of Hepatitis B Surface Antigen, advises against mouth pipetting and provides information on alternative pipetting devices. Early this year, the WHO unit dealing with Safety Mea- sures in Microbiology (SM M) convened an expert group which developed a basic course outline for good labo- ratory practice, including the use of mechanical and other pipetting aids. Safety pipet- ting aids will also be describ- ed in a document on Labo- ratory Equipment and Safe- guards to be issued shortly. H FA/2000 Plans of Action Taking Shape The International Confer- ence on Primary Health Care, held in Alma-Ata, USSR, in September, 1978, was one of the few major intergovern- mental conferences which did not develop a ready-made "action plan" for govern- ments to implement. The De- claration of Alma-Ata reaf- firmed "Health for All by the Year 2000" as the major social goal of governments and de- fined primary health care as the key to its achievement. But it was left to each govern- ment to decide how these principles should be imple- mented, in a manner most ap- propriate to the people's needs. Now, results are becoming widely apparent. During the lastfew months national strat- egies and plans of action for attaining "Health for All" have been flowing into WHO's six regional offices. There, regional strategies have been formulated as a prelude to the development of a global strategy at the World Health Assembly in May next year. While national strategies vary widely in scope and depth, they have one com- mon characteristic: they are based on the principles of the Declaration and Report of Alma-Ata, and aim at ensuring universal access to health care. Further, almost all have gone through a pro- cess of wide consultations among many government de- partments—and frequently non-governmental organiza- tions—a recognition of the principle that health cannot be improved solely by the action of the health services. Although many govern- ments have produced com- prehensive strategies for at- taining "Health for All", they are viewed as part of a con- tinuing process and subject to change in the light of future developments. Dr Halfdan Mahler, WHO's Director-General, speaking to Regional Committees during their annual meetings in Sep- tember and October, said, "we must never imagine that a strategy that is to take us to the year 2000 can be finalized in all its details in 1980. The main lines of action can cer- tainly be defined, but ample scope must be left to act in many different ways along those lines." Strategies are guides for future action not straitjackets to be lived in for 20 years, he stressed. WORLD HEALTH 1980 Subscription Rates US$ Sw. fr. One year 15. -- 25. Two years 27-- 45.--- Three years 36. 60.-- ORDER FORM Please enter my subscription to "World Health" as follows: One year ❑ Two years ❑ Three years ❑ I enclose cheque/international postal order in the amount of : Name Street: City: Country: World Health, WHO, Avenue Appia, 1211 Geneva 27, Switzerland. World Health is also distributed through the network of international bookstores and subscription agencies. For payment in national currencies, please contact your usual bookseller. cW9-A throat operation kept alive this little Indonesi drohtberi one of the lethal communicable diseases. (Phoio WHO:EPHL. Matlovsk-i