Anthrax control and research, with special reference to national programme development in Africa: memorandum from a WHO meeting.

Memoranda! Memorandums Anthrax control and research, with special reference to national programme development in Africa: Memorandum from a WHO meeting* The prevalence of anthrax in both animal and human populations has been increasing in Africa. It was therefore appropriate for this WHO meeting to be convened in an endemic area of the Western Prov- ince of Zambia in 1992. The participants reviewed anthrax epidemiology and control in some African countries, elaborated national anthrax control and research programmes in Africa, discussed interna- tional cooperation and work plans, and elaborated recommendations for anthrax control in Africa. The discussions centred on anthrax surveillance and reporting systems, diagnosis, vaccine production and immunization, disinfection and decontamination, carcass disposal, treatment of human cases, health systems, as well as intersectoral cooperation between public health services, veterinary services and other services such as wildlife conservation, so that national control programmes could take full account of the conditions prevailing in epidemic situations in Africa. The recommendations are applicable in other regions where anthrax poses similar problems in public, animal and environmental health. Introduction WHO-coordinated activities From 1948 WHO has been promoting activities on anthrax control and research. In the last few decades, a number of countries, particularly in Europe, have reduced morbidity and mortality due to anthrax in both humans and livestock to negligible levels through international cooperation and support. However, many countries are still endemic today for * This Memorandum is based on the report of a WHO meeting held in Mongu, Zambia, on 22-27 September 1992. The partici- pants were: Katinka de Balogh, Lusaka, Zambia; G.C. Bbalo, Mongu, Zambia; R. Bohm, Stuttgart, Germany (Vice-Chairman); H.G.B. Chizyuka, Lusaka, Zambia; Bengat Kigan, Kabete, Kenya; G.L. Komba, Dar es Salaam, Tanzania; P.M. Muyoyeta, Lusaka, Zambia (Rapporteur); L.M. Tuchili, Lusaka, Zambia; P.C.B. Turnbull, Porton Down, England (Chairman); V. de Vos, Skukuza, South Africa. Representative of the Food and Agricul- ture Organization of the United Nations: D.H. Roberts, Lusaka, Zambia. WHO Secretariat: T. Fujikura (Secretary). Requests for reprints or the full report of the meeting (WHO/CDS/VPH/93. 117) should be sent to Chief, Veterinary Public Health, Division of Communicable Diseases, World Health Organization, 1211 Geneva 27, Switzerland. A French transla- tion of this Memorandum will appear in a later issue of the Bulletin. Reprint No. 5447 anthrax in both human and animal populations, including wildlife, and the disease has a great public health, environmental, and socioeconomic impact in Africa and Asia. In view of the above, the Veterinary Public Health unit of WHO formed a working group of experts for anthrax control and research comprising four subgroups: (1) epidemiology and information exchange, (2) disinfection and decontamination, (3) vaccines and vaccine development, and (4) consulta- tive group for problems in developing countries. In 1987 the group produced "A guide to the diagnosis, treatment, and prevention of anthrax" (document WHO/Zoon./87. 167), and recently "Guidelines for the surveillance and control of anthrax in humans and animals" (WHO/Zoon./93.170). The group has also advised and served various countries in such matters as anthrax surveillance, diagnosis, vaccine production and control, immunization campaigns, disinfection and decontamination, carcass disposal, intersectoral cooperation, and the provision of refer- ence and research materials. A number of missions have been carried out in Africa and Asia, with others to follow. The group's meeting in Zambia in 1992 with experts from some African countries reviewed the status of anthrax in Africa and discussed further strengthening of international cooperation. Bulletin of the World Health Organization, 1994, 72 (1): 13-22 © World Health Organization 1994 13 Memorandum Anthrax epidemiology and control in Africa Zambia Anthrax vaccination campaigns used to be compul- sory, but the campaigns ceased some years ago due to success in controlling the disease in livestock. A large-scale outbreak in game animals in Luanguwa National Park occurred in 1987, the enzootic origin of which could not be clearly identified. Circumstan- tial evidence suggests that the enzootic was associa- ted with several years of severe drought, during which more animals became concentrated in limited watering places. Since anthrax cases in animals, wildlife and humans continued to occur sporadically, a vaccination campaign was again initiated although the coverage was limited to endemic areas at the time of outbreaks. Quarantine and restriction of ani- mal movement from/to endemic areas were also rein- troduced. There was a direct relationship between out- breaks in 1989-91 and previous outbreaks in the plains and plain edges. These were characterized by sudden occurrences of multicentric foci of infection with many sudden animal deaths not preceded by any observed illness. Many such outbreaks occurred from 1989 to 1992 (2 outbreaks in 1989, 20 in 1990, 25 in 1991 and 2 in 1992), and these were linked to unusually high rainfalls with flooding. Where vacci- nation campaigns were carried out and high coverage achieved, deaths in animals ceased two weeks after the vaccination. However, anthrax deaths still contin- ue in these areas because of the continuous inflow and outflow of cattle. The Western Province has a cattle population of 556 000, the animals being raised in a fixed area or with a transhumance type of management. Their den- sity is 10 per km2 and they constitute the main eco- nomic background of the Province. Since 1970, there have been 1 to 3 anthrax enzootic outbreaks per year. Vaccination coverage in this Province is less than 50%. Regulations to control cattle movements be- tween districts in this Province are very strict, but difficult to implement in areas where other than main roads are taken. The traditional management system, exchanges and gifts of cattle, and herding arrange- ments make it difficult to control interdistrict move- ments of livestock and products. Jackals and hyaenas may also bring about some movement of carcasses and hides. It is a social custom for people in Zambia to skin, butcher and eat animals that die unexpectedly although villagers do understand that such animals may have had a serious transmissible illness such as anthrax. This situation leads to delay in notifying the veterinary office responsible for anthrax control. Burying and/or burning of carcasses require extra labour, and in many districts there is a lack of suffi- cient wood for incineration of carcasses. Disinfection and decontamination are impractical in many of the affected regions at present. Other problems in controlling anthrax are due to (1) lack of cooperation over vaccination by farmers; (2) delays in diagnosis because regional laboratories lack facilities for confirming the diagnosis of anthrax and specimens have to be sent long distances to the Central Veterinary Research Institute (CVRI) in Lusaka; and (3) funding problems for vaccination and diagnosis programmes. In the Western Province, anthrax is suspected or confirmed when (1) the cattle owner opens the car- cass and notes an enlarged spleen; (2) human cases result after handling or consuming meat from ani- mals that died of anthrax; and (3) specimens are examined in the laboratory (at present this can only be done at the CVRI, Lusaka). During the meeting the participants visited endemic areas in the Kalabo district, some 60 km from Mongu, accompanied by national and local staff. They observed some of the endemic situations and met patients as well as villagers who had suf- fered from anthrax after eating contaminated meat or through their direct involvement (skinning, cutting and other activities) with animals that had died from unknown causes. A research programme was recently initiated at the CVRI, Lusaka, to carry out a serological survey on cattle, humans and dogs in the endemic Western Province using enzyme immunoassay (EIA) with a cell-free protective antigen. Technology transfer of anthrax vaccine production and control has also been initiated, with the support of WHO, FAO and other international agencies. United Republic of Tanzania At the last census in 1984, livestock populations in this country were 13 million cattle, 6 million goats, 3 million sheep, 2 million horses, 14 million poultry, 200 000 donkeys, as well as the world's largest num- ber of wild animals. Wild and domestic animals co- exist and wild animals play a significant role in transmitting anthrax to domestic animals. Sporadic anthrax occurrences are seen in most parts of the country, but basically the disease is enzootic in pas- toral areas. From 1981 to 1990, some 97 585 cattle died of anthrax, representing 2.3% of all cattle deaths in this period. The enzootic state in pastoral areas is mainly due to improper disposal of carcasses and the conse- quent persisting environmental contamination. Diag- WHO Bulletin OMS. Vol 72 199414 Anthrax control and research In Africa noses can be made on the spot on the basis of clini- cal manifestations such as high temperature (42 °C), sudden death, or a carcass with blood oozing from the orifices and which does not stiffen. Regulations require that such carcasses are not opened and that blood smears from the tip of the ears are prepared and stained with Giemsa or methylene blue. Field staff readily recognize anthrax cases on these criteria and only a few cases are referred for further labora- tory investigation. Quarantine, supervised disposal of carcasses, and ring vaccination with routine vaccination cam- paigns have proved quite effective control methods in livestock. For disposal of carcasses, Tanzanian legislation prescribes burying the carcasses 2 m deep in the ground with quicklime; disinfection of contact areas with formalin (30%), and caustic soda (40%); and chlorination of watering points. Altematively, the carcasses and materials must be incinerated. These regulations are often not implemented proper- ly, hence the perpetuation of the disease in enzootic areas. In such areas, routine animal vaccination is necessary to control anthrax. Since 1984, anthrax vaccine has been produced in the Vaccine Production Institute in Dar es Salaam, but there are problems of unreliable electricity sup- ply, shortages (raw materials, reagents, seed cultures, bottles and packing materials), and lack of funds for field trials of the vaccine. Research activities at the Institute have been concerned with development of a combined anthrax/black-quarter vaccine. Among wildlife, quite marked anthrax outbreaks have been experienced in the Manyara and Tarangie National Park (Arusha district) during drought years. Heavy concentrations of wildlife in and around watering points render these places important sourc- es of infection. Biting insects may contribute to the transmission of anthrax among wild animals; preven- tion and control measures are similar to those for livestock, i.e., by incineration or burying of carcasses at least 2 m deep in the ground with quicklime, and by chlorination of watering points.. However, these measures are difficult to implement with wild ani- mals. Quarantine, vaccination, and detection/disposal of carcasses before they are opened up by scavengers can help to minimize contamination. Kenya In Kenya, anthrax is classified as a notifiable and emergency disease and is covered by legislation to ensure proper disposal of carcasses, quarantine of the affected area, and emergency vaccination. The dis- ease occurs sporadically throughout the country and is more common in unusually wet years. The Central Veterinary Laboratory, Kabete, and regional/district laboratories are active in diagnosis and control of anthrax, cases of which tend to be reported only when humans are affected after eating meat from anthrax-infected carcasses. This occurs more com- monly in pastoral districts in the north, and to a les- ser extent in the central districts. In the pastoral nor- thern districts the disease is common in cattle and camels and some endemics have also been seen in humans. As well as being a common custom of the peoples in these areas to eat the meat from sudden- death animals, the remains are not properly disposed of and are therefore spread about to other places by wild animals. In the central agricultural parts of Kenya, outbreaks are sporadic (<10 per year) and may only affect one or two animals at a time. In the coastal region, reports of cases have been few and infrequent for many years. Very large numbers of doses of combined anthrax/ black-quarter vaccine are administered annually (703 549 in 1990, 483 067 in 1991). Other measures for controlling anthrax include: - regulations for the proper disposal of carcasses; - prohibition of selling meat from an animal that died of an undiagnosed cause; - quarantine of an affected area and vaccination, which should be carried out until three months after the last reported case; - implementation of proper disinfection and decon- tamination procedures for contaminated areas and materials; and - education campaigns by public health and veteri- nary staff aimed at educating people not to eat uninspected meat. South Africa In South Africa anthrax was first described by a his- torian/traveller in 1838 and first confirmed scientifi- cally in 1876, although Bacillus anthracis has been isolated from bone diggings in the Kruger National Park which date back more than 200 years. Incidence of the disease increased markedly in the early years of this century, reaching a peak in 1923 when an estimated 30 000 to 60 000 animals died of anthrax. Legislation to control anthrax was issued in 1911 and the government decided to provide free vaccination to all livestock owners in 1923. Annual vaccination of cattle remained compulsory, with con- sequent decline of anthrax outbreaks in cattle from about 1000 a year to <3 a year, cases also declining in humans, until the government-provided vaccina- tion services for the livestock population ceased at the end of 1987. Since then the number of vaccina- tions has declined dramatically. WHO Bulletin OMS. Vol 72 1994 Memorandum Anthrax in livestock in South Africa rarely pro- gresses beyond the primary cases, being rapidly brought to a halt by effective control measures as follows: - on confirmation of the diagnosis the area or farm is placed under quarantine which is enforced by government veterinary staff (quarantine is lifted three weeks after vaccination or three weeks after the last anthrax case diagnosed, whichever is the later); - all cattle on the farm and in neighbouring areas are vaccinated by the Department of Animal Health; - chemotherapy with antibiotics (such as a combi- nation of penicillin and dehydrostreptomycin) is permissible but must be followed by vaccination 10-14 days afterward (antibiotics are not allowed 10 days before or after vaccination); - infected animals are isolated and destroyed under the supervision of an authorized officer; - anthrax carcasses are not allowed to be opened and must be incinerated or buried with liberal amounts of slaked lime; - disinfection of the premises is effected with a 5% solution of formaldehyde or disinfection accord- ing to the WHO Guidelines (unpublished docu- ment WHO/Zoon./87.163, 1987). Diagnosis is confirmed by means of blood smears examined by a state veterinarian or at one of 14 regional laboratories. Tissue samples are sent to the Veterinary Institute at Onderstepoort for confir- mation by culture. The live spore (Steme strain) vaccine is manu- factured at the Institute in Ondestepoort, and costs 0.30 rand (US$ 0.10) per dose. A marked decline in vaccine sales since 1988-89 reflects a complacent attitude by farmers following long periods of free- dom from anthrax outbreaks and an inability to enforce the law on vaccination. In the case of wildlife, 52 species have been found to be susceptible to anthrax in the Kruger National Park including kudu, nyala, and roan which are highly vulnerable. Adult animals are evidently more vulnerable than young or sub-adults. Scaven- gers such as vultures and hyaenas play a major role in disseminating anthrax spores. Blowflies feed off body fluids from opened carcasses, then deposit infective faecal and vomit droplets on vegetation which is then eaten by browsers such as kudu. Out- breaks typically take place towards the end of winter till the beginning of summer, before the first major rains occur. Factors influencing the outbreaks in wild animals in the three national parks of South Africa are: (1) concentration of the animals, (2) overutiliza- tion of vegetation, (3) stagnation and concentration of water resources, and (4) nutritional stress. Standard control measures for livestock cannot be applied in wildlife so that in the event of an out- break of anthrax in wildlife, vaccination is carried out using disposable darts fired from a helicopter. This method has been very successful in the Kruger Park and neighbouring game-ranching areas. Apart from immunization, control in wildlife rests on incinerating the carcasses (when found), preventing water-holes from getting infected via vultures, etc., veld burning practices, and preventing large accumu- lations of game through culling procedures. National anthrax control and research programmes Surveillance and data collection For anthrax control to be achieved, surveillance and data collection procedures need to be improved. This means that all suspected clinical cases should be confirmed by reliable laboratory tests and all unex- plained, sudden deaths in animals should be investi- gated. Although anthrax remains a human and animal health problem in Africa, and the cause of significant economic losses, the true incidence and effect of the disease in many African countries is uncertain. This results from a failure to apply standard methodol- ogies of surveillance and data collection. In many developed nations where strong action is taken to prevent the disease, anthrax has almost been eradi- cated. Correct surveillance and data collection require the following. (1) All suspected clinical cases and unexplained deaths should be investigated and the diagnosis con- firmed by laboratory tests (i.e., appropriately stained blood smears, isolation of B. anthracis, and patho- genicity (and where appropriate) virulence or sero- logical tests). (2) Field surveillance stations should be created, and headed by a qualified veterinarian who should be able to make necessary investigations and collect appropriate samples for confirmation. The stations should be supplied with sufficient glass slides and a good quality microscope for examination of smears collected from all animals dying unexpectedly. The field station should be able to collect blood smears and animal and environmental specimens from the sites of animals suspected of being victims of anthrax, and should submit these to a laboratory equipped to carry out confirmatory bacteriological and other tests. WHO Bulletin OMS. Vol 72 199416 Anthrax control and research in Africa (3) The field surveillance stations should have stan- dard questionnaires to issue to all animal owners for completion during investigations. In addition, in the event of major outbreaks, it may be appropriate to establish a task force composed of staff from the local, central and academic veterinary services as well as the public health and, if relevant, wildlife services, to investigate the outbreak and make rec- ommendations on the action to be taken. Serology is useful but, at present, the necessary antigen is not commercially available. Thus serological tests are confined to specialized centres and for research pro- jects rather than routine diagnosis. Reporting and information support It is estimated that anthrax is still not a notifiable disease in about 54% of African countries. Another factor contributing to inaccurate information is the frequent failure by field officers to recognize clinical cases and by regional laboratories to provide the necessary support tests. Insufficient intersectoral cooperation is yet another factor leading to inaccur- ate reporting. Proper reporting and provision of information require that: (1) field surveillance stations should keep records of all cases of anthrax and the officer in charge should prepare regular reports for submission to all relevant services; (2) all suspected cases of anthrax should be con- firmed by a laboratory to ensure accuracy in reporting; (3) livestock owners should be compelled by law to report all unexpected deaths; (4) livestock owners who willingly report the dis- ease should be given support in the form of free vac- cination, disinfection and disposal of carcasses; (5) in national parks and game management areas, all suspected cases should be reported to the field surveillance stations; (6) a leaflet on the disease should be supplied to all field stations (briefly describing anthrax, the animals likely to be affected and disease transmission, biol- ogy of the bacillus, symptoms, treatment, prevention, decontamination and disposal of carcasses). Disposal of carcasses and subsequent disinfection and decontamination Proper disposal of carcasses and subsequent disinfec- tion and decontamination of infected places are car- ried out with a view to interrupt the epidemiological cycle of the disease. Regarding the disposal of car- casses, there can be a problem when the disease is not recognized immediately and the carcass is incor- rectly handled. Similarly, the lack of availability of appropriate disinfectants is often a problem in Afri- can countries. Those on the market at present have not proved effective against anthrax spores, and the possibility of using locally available disinfectants or other methods should be investigated. The following approaches need to be considered: (1) Physical (burning and burying). Burning, when correctly done, is the most reliable method of destroying spores. Burial entails the possibility of leaving long-term environmental contamination. However, burning requires large amounts of fire- wood which may not be available. Disposal needs to be supervised by veterinary officials or other appro- priate persons such as members of surveillance teams or anthrax control task forces. Ideally, the effectiveness of the disposal procedure should be confirmed bacteriologically. (2) Chemical. Before any locally-produced chemi- cals can be recommended, their sporicidal value must be confirmed in laboratory tests. Disinfectants must be kept in reasonable quan- tities by all field surveillance stations and should be used only under he supervision of trained staff. Leg- islation should be formulated on the collection and disposal of carcasses and on the disinfection of con- taminated premises. The meat industry, including abattoirs and other animal product industries (hides and skins, wool and hair, bone meal, etc.) should maintain a sufficient quantity of disinfectant to disin- fect their premises in the event of inadvertent anthrax cases. Information leaflets on the disinfec- tion and decontamination of anthrax contaminated premises should be readily available to farmers and surveillance teams. Functions and role of diagnostic laboratories For proper monitoring of anthrax, a laboratory should be able to: - support an investigation and confirm all suspect- ed cases of anthrax in the shortest possible time; - develop procedures and instructions and provide the materials for field personnel in regard to col- lecting specimens and submitting them to the laboratory; - perform the most appropriate laboratory tests. A flow diagram of the suggested procedure for iso- lation and identification of B. anthracis and con- firmation of diagnosis is shown in Fig. 1; - communicate the findings to all groups con- cerned; - develop and maintain the nationally required reporting system. WHO Bulletin OMS. Vol 72 1994 17 Memorandum Fig. 1. Flow-diagram of suggested procedure for Isolation and Identification of B. anthracis and confirmation of diagnosis. | ~~~~~~Undercertain circumstances, testing inl ] ~~~~~animals may be necessary/unavoidablel l i i ~~~~~~~~~~~~~62.5°ICx 15 min_ |(Koch's postulates)|i HUMAN SPECIMEN ANIMAL SPECIMEN /MATERIAL ENVIRONMENTAL SAMPLE Fresh specimens from animal Old /decomposed or processed with suggestive clinical signs/ specimens (bonemeal, hides, history etc.) L -_-_-_-_-_, Antigen detection (e.g. Ascoli test) Blend to suspend in 2 volumes of or detection of anthrax toxin sterile distilled water Prepare + 10 ml volumes of undiluted and 1:10, 1:100, 1:1000 dilutions of suspensions (dilute inIV IF rsterile distilled water) M'Fadyean stain Direct plate on smear of on blood agarblood, vesicular o b (M'Fadyean or other tissue i stain on smear fluid Plate out unheated dilutions of blood at(see below) death) Place in 62.50C water bath for 15 min (alternatively, "alcohol shock" by adding equal volumes of 95-1000Oo ethanol and holding 1 hour) Plate out heated /alcohol shocked dilutions (see below) Spread 10-100 gtl of each Spread 250-300 gl of each dilution on blood agar + dilution (before and after polymyxin (unheated/ heating/alcohol shocking) on unshocked dilutions) or plain PLET agara blood agar (heated/alcohol shocked dilutions) 37oC overnight 37oC x 48 h Test typical colonies for lack of haemolysis, lack of motility, sensitivity to gamma phage and sensitivity to penicilin Transfer pin-head quantity of growth from suspect colony to ± 2.5 ml defibrinated blood (any species, though horse seems to be best) 37°C x 5 hours to overnight Make smear and do M'Fadyean stain Presence of typical capsulated bacilli (pink capsule surrounding dark blue bacilli, often square-ended and sometimes single but usually in chains of two to many) is definitive for virulent Bacillus anthracis a PLET = polymyxin-lysozyme-EDTA-thallous acetate agar. WHO Bulletin OMS. Vol 72 199418 Anthrax control and research In Africa Production and supply of anthrax vaccine For an anthrax vaccine to be qualified for use, it must meet certain conditions and standards. Some of these are: - the vaccine should be produced in accordance with acceptable intemational standards and agreed procedures, including potency, abnormal toxicity, and other quality control tests in line with those given in the report of the WHO Expert Committee on Biological Standardization (WHO Technical Report Series No 361, 1967); - the vaccine should be safe for all the target ani- mal species; - the vaccine should be efficacious and give at least 12 months' protection. In addition: - the vaccine must be readily available when required; - field officers should have storage facilities for the vaccine; - contingency stocks of the vaccine should be available, in the care of the national task force; - research into an improved vaccine should be encouraged with the aim of producing one that is more easily administered and has longer-lasting protection than current vaccines. Food hygiene aspects, training and education In Africa, many people have died of anthrax, often after consuming infected meat or handling infected carcasses. Avoidance of the problem depends on the following considerations: - meat must be properly inspected before being distributed for consumption (this includes meat from animals culled in game parks); - animals that die unexpectedly or the carcasses of animals "found dead from an unknown cause" should not be butchered and distributed for human consumption; - public awareness of the dangers of consuming such meat should be intensified through semi- nars, the media and posters; - regulations for and training in meat inspection should be regularly reviewed; - all meat processors should be equipped and trained to decontaminate and disinfect their premises in the event of an anthrax-infected car- cass entering the processing line. Drying is a common method of meat preserva- tion in Africa and in this form the meat can be readi- ly transported over long distances and kept for a long time. However, this is a potential means of spreading anthrax spores if the meat is derived from an infect- ed animal. Task forces and intersectoral cooperation Intersectoral cooperation is essential for effective control of anthrax. In developing countries where anthrax is still a great problem, the formation of task forces must be given high priority. Such task forces should be drawn from the following Ministries: Agriculture, Food and Fisheries; Health; Tourism (Wildlife); and Environment. The operations of task forces must range from the outbreak level to national level. Within each interested ministry there should be an officer to attend to anthrax-related matters, including: - surveillance and reporting/notification; - public awareness; - field facilities for diagnosis, carcass disposal, dis- infection and decontamination, and vaccination, including ensuring that stocks of vaccine and dis- infectants are held under appropriate conditions of storage; - food hygiene aspects; - quarantine. Research requirements and programmes in Africa The participants agreed on the need for research in the following areas relating to control of anthrax under the conditions prevailing in Africa. (i) Epidemiological factors contributing to anthrax outbreaks in Africa. These are: mechanisms of infec- tion through exposure to contaminated soil, water and other materials; mechanisms of anthrax infection in humans; transmission dynamics of anthrax among livestock, wild animals and humans; the effect of seasonal and climatic factors on anthrax occurrence, in particular the effect of drought in Africa; and socioeconomic customs in African villages and the anthrax endemic state. (ii) Operational research for task forces concerned with anthrax control in Africa. The subjects are: col- lection of diagnostic materials and their transport to diagnostic laboratories; applicable methods of car- cass disposal under conditions prevailing in Africa; applicable methods of disinfection/decontamination of contaminated sites and areas in Africa; first-aid action to be taken for anthrax patients; intersectoral cooperation, including wildlife service sectors; and cost/benefit analysis of anthrax control operations in Africa. WHO Bulletin OMS. Vol 72 1994 19 Memorandum (iii) Anthrax vaccine development and vaccination campaigns. There are concerned with: vaccine pro- duction and control in Africa; vaccine efficacy and effectiveness as applied in Africa; stability, duration of immunity and safety of the vaccine; and develop- ment of oral anthrax vaccine for animals. (iv) Research in diagnostic methods in Africa. The subjects are: development of simple, economical anthrax diagnostic methodology for Africa; develop- ment of serological methodology for surveillance and diagnosis; and identification and antimicrobial sensitivity testing on B. anthracis isolated from clini- cal samples, environmental materials, and food. (v) Operational research in animal slaughter hygiene. These are: biosafety aspects of animal slaughter; and inspection of slaughtered animals with special attention to anthrax. (vi) Other research areas: intersectoral cooperation, health systems and legislation for anthrax control in Africa; best methods of utilizing anthrax-contaminat- ed pastures and lands for safe agricultural purposes; and pathogenesis of anthrax to better understand the risks in, for example, slaughterhouses. International cooperation The group agreed upon the following work plans for 1993-95 and action to be taken by participating countries under the auspices of working group cooperation: (1) To facilitate prompt collection of epidemiologi- cal information upon the onset of an anthrax out- break, a "broad sheet" (a small but comprehensive check-list on action to be taken by livestock owners in the event of an anthrax outbreak) should be designed and distributed in endemic countries. The livestock owner should be encouraged to follow the directions of the broad sheet to inform the nearest veterinary and/or public health offices so that further control contingencies can be set in motion. (2) Moves should be made to ensure that diagnostic laboratories be equipped with simple, essential mini- mum facilities, equipment, and trained technical per- sonnel. Microscope smear preparation and specimen collection kits should be available for distribution to local veterinary, public health or other appointed officers for prompt collection of diagnostic speci- mens. (3) Laboratories producing anthrax vaccine in Africa should be identified together with their type of vac- cine, capacity, standard, stability, safety and control of the production, as well as the price and amount of stock for possible distribution to outlying districts or export to other countries as necessary. The cold chain throughout he process of vaccine application also needs to be re-examined, together with vaccine efficacy and effectiveness. Availability of human anthrax vaccine for people in at-risk occupations should be established. (4) More information should be collected on the costs of implementing task force control of anthrax, including the resources required for disinfec- tion/decontamination, carcass disposal, meat inspec- tion, transportation, public education, and any other activities required. (5) Training courses for technical personnel at local/national levels, and educational campaigns for the general public in endemic areas, should be orga- nized. For this purpose, guidelines for diagnosis, pre- vention and control, video films, posters, and diag- nostic kits should be prepared and distributed in the selected model countries. (6) The model country approach for improved anthrax surveillance, control and associated research, proposed at the working group's meeting in 1991 (document WHO/CDS/VPH/91.98), would be initiat- ed with minimum further delay in Kenya, United Republic of Tanzania and Zambia, and any other countries with a marked interest in being involved. Also in line with the proposals contained in the 1991 report, the model countries would closely examine the best methods under their individual circum- stances for conveying and imparting the necessary information and instruction at the various levels of infrastructure, from the farmer/owner through the veterinary services to the Ministry of Agriculture (or equivalent). (7) To facilitate the earliest possible implementation of the above plans a training workshop on anthrax surveillance, diagnosis and control should be orga- nized for technical personnel from countries in Africa. WHO is planning to organize a training workshop in collaboration with related FAO and WHO Collaborating Centres in Europe in the 1994-95 biennium. Conclusions Anthrax still remains endemic in many parts of Africa, despite the efforts of the public health, veterina- ry, agriculture, environmental and social sectors to control the disease. Local socioeconomic circum- stances and customs, together with the complexity of anthrax epidemiology in Africa (from extensive spread of contaminated areas and agricultural lands to the intermingling of livestock with wild animals) are also factors preventing the implementation of effective control programmes in Africa. However, WHO Bulletin OMS. Vol 72 199420 Anthrax control and research In Africa current science and technology could be applied to anthrax control, and plans for international coopera- tion in support of national control programmes would be invaluable. The problems and needs for further collabora- tion in controlling anthrax in Africa were usefully identified through visits to endemic areas in the Kalabo District, Western Province, Zambia. The working group's activities will continue in line with the agreed work plans. Recommendations (1) Surveillance and reporting. While appropriate legislation requiring notification of anthrax was in place in most countries, the problem lay at the level of the farmer/owner reporting to the veterinary field officer or equivalent. It was therefore recommended that: (a) the incentive for livestock owners to report anthrax should be the offer of free vaccination of the remainder of the herd following laboratory confirma- tion of the disease; (b) a concerted effort should be made to insert into legislation a clause that hospitals and clinics should report cases of human anthrax to the regional/district veterinary officer and/or find other ways and meth- ods of establishing/ensuring close cooperation between medical, veterinary and wildlife services. In view of the frequent problem of distance between the sites of communities where a case or outbreak may occur and the nearest veterinary sta- tion, it was considered that it should be an accepted aim that every unexpected death among livestock should, through appropriate means, result automati- cally in a blood smear for examination at the first opportunity. The "appropriate means" might be a person of standing in each community who has been given adequate instruction. (c) better monitoring by veterinary field staff of unexpected deaths would assist in improving anthrax surveillance; (d) each participating country should choose an area for intensive study to determine the real incidence of and reasons for unexpected death in that area; (e) the recommendation on "establishment of nation- al and regional task forces", contained in the WHO Guidelines for surveillance and control of anthrax in humans and animals (unpublished document WHO/Zoon./93.170, Annex VII, page 72) should be implemented. (2) Diagnostic laboratory support. Laboratory cul- ture should be regarded as an essential back-up pro- cedure for diagnosis and this should be made pos- sible by provision of the appropriate equipment, materials and instructions at least at the district vet- erinary laboratory level. Research and development on prototype alternative "on the spot" test systems not requiring any expensive piece of equipment, such as a microscope, should be a priority. Simple guidelines on clinical diagnosis of anthrax in animals and in humans should be elab- orated to ensure optimal chances of correctly deter- mining the incidence of anthrax in an area, even in the absence of diagnostic laboratory support. (3) Disposal of carcasses, disinfection and decon- tamination. Research should be carried out in the participating (model) countries to determine the con- ditions under which a "rendering policy" might be established. The recommendation was in four parts: (a) the participating countries should be supplied with information on rendering plant design, con- struction, and operating needs such as amount and type of fuel required; (b) these participating countries should carry out a feasibility study on establishment of rendering plants, transportation thereto of carcasses, and supply of the necessary fuel; (c) some studies should be carried out to determine the efficacy of burning as a means of decontaminat- ing the site of an anthrax carcass after the latter has correctly (or incorrectly) been removed from that site; (d) research should be carried out into the design of a formal disinfection procedure applicable to the conditions pertaining in Africa. (4) Vaccines and vaccinations. Follow-up investiga- tive surveys on vaccinated animals should be carried out so as to examine: (a) the possible effects on vaccine efficacy of vari- able production, storage and distribution conditions; (b) sero-conversion rates in vaccinated animals; (c) duration of vaccine-induced protection. It was accepted that in Africa, as in Europe and North America, human vaccine should only be used for persons in at-risk occupations. (5) Food hygiene aspects. Hygiene regulations appear to exist in most African countries, but prob- lems appear to lie with implementation of these reg- ulations, especially in rural areas. In general, inspec- tion is only required for meat destined for sale. It was recommended that the new aim should be that all livestock carcasses destined for human consump- tion should be inspected. WHO Bulletin OMS. Vol 72 1994 21 Memorandum A person at village level should be trained to inspect all livestock carcasses destined for human consumption. This person might be the same person as proposed in recommendation (1) above, appointed to take smears from the carcass of any animal dying unexpectedly. Equivalent provision should be made for inspection of carcasses resulting from culling in wildlife and proposed for human consumption. A way should be found to increase public awareness of this matter. (6) Task forces and intersectoral cooperation. Poor communication and collaboration between veterinary and medical services constitute a major problem in the control of anthrax. A way should be found to open channels of communication between these ser- vices on zoonotic diseases and to make it possible for them to share necessary facilities. One way of ensuring improved communication would be to offer combined courses on various zoonoses. The need for intersectoral cooperation and communication was also stressed in relation to veterinary and wildlife staff. The other area of intersectoral cooperation that needed improvement was the farmer/wildlife staff link. Model country personnel would also examine ways of improving this aspect wherever necessary. Permanent national/district task forces, with every member knowing clearly his/her role, should be established for immediate mobilization when needed. The district task force should include diag- nostic capabilities and have established plans of action in line with local conditions and circumstan- ces. These plans should include instructions on the source and use of vaccine, disinfectants, etc. WHO Bulletin OMS. Vol 72199422