TB revisits the industrialized world

20 World Healtk • 46th Yeor, No. 4, July-August 1993 TB revisits the industrialized world Hans Rieder & Mario Raviglione BCG vaccination in Paris . With increasing immigration countries need effective methods of controlling TB . A great deal of attention has been given to the increase of tuberculosis in the USA, which was frrst noticed in 1986. Similar increases are occurring in other industrialized countries, including some in western Europe. This article will summarize the extent to which the TB epidemic has returned as a public health threat to industrialized countries. USA. Between the 1950s and 1985, TB notifications decreased at a steady rate of 5% each year. However, between 1985 and 1991 , TB notifications increased by 18%, resulting in an additional 39 000 unexpected cases of TB. Over half of these new cases were found among 25 - 44-year-olds. Of the 26 283 new TB cases in 1991, two-thirds occurred among racial and ethnic minorities, and over a quarter among immigrants. It is believed that infection with the human immunodeficiency virus (HIV) has largely contributed to the increasing trend: 4.3% of all AIDS patients suffer from TB. Likewise, ll % of all TB cases are HIV -positive; in certain areas of the country the rate is as high as 50%. Homelessness, drug abuse, deterioration of living conditions and of health care delivery to people, and immigration have also been implicated as factors contributing to the rapid increase of TB in the USA. Western Europe. In recent years, increases in tuberculosis case notifications have been recorded in Denmark, Ireland, Italy, Netherlands, Norway, Spain and Switzerland. TB case notifications have levelled off in Austria, Sweden and the United Kingdom, and continued to decline in Belgium, Finland, France, Germany, The decline in tuberculosis incidence observed for several years in industrialized countries appears to have slowed or even reversed. and Portugal. The highest case rate was found in Portugal (57.6 per I 00 000 population in 1991) and the lowest in Denmark (6.5 per lOO 000 in 1991 ). However, all countries except Portugal reported rates lower than 25 per I 00 000. Deaths due to tuberculosis have uniformly decreased in all countries. The highest death rate was in Portugal (2.8 per I 00 000 population in 1990) and the lowest in the Netherlands (0.3 per 100 000 in 1989). All other countries had death rates below 2.4 per I 00 000. Among the indigenous population of most western European countries, tuberculosis has become a disease of the elderly. The notable exception is Portugal where in 1990 over half the cases occurred among 15 -44-year- olds. In Denmark, Netherlands, Norway, Sweden and Switzerland an increasing number of cases among foreign-born people has changed the expected downward trend. HIV infection appears to contribute only marginally to overall tuberculosis morbidity, but it is important in parts of France, especially Paris and surrounding areas. Tuberculosis is also common among HIV -infected persons in Italy, Portugal and Spain. Australia. Case notifications have slightly increased from 5.6 (per 100 OOO)·in 1986 to 5.9 in 1990. Increases in new case rates have been seen in New South Wales and Queensland. In 1991, 15 -44-year- World Health • 46th Year, No. 4, July-August 1993 21 Homeless people in large cities are at increased risk of TB . In western Europe, TB had become a disease of the elderly but is now spreading to other age groups too. olds accounted for 41% of all cases, and those aged over 64 years for 26%. Foreigners (mainly from south-east Asia) constituted 66% of all cases in 1991, and Aborigines only 15% of the cases among Australians. Death rates have remained constant between 0.3 and 0.5 (per 100 000) during the past ten years. The impact of HIV on the TB situation in Australia is limited: only 2.5% of TB cases in New South Wales were HIV-seropositive in 1991, and only 0.4% of all AIDS cases so far reported had TB. New Zealand. There were 335 TB cases in 1991 at a rate of 9.9 per 100 000. TB mortality rates decreased from 0.9 to 0.5 (per 100 000) during the period 1980-88; in 1991, the rate was 0.4. Canada. The number of TB case notifications and rates has stagnated over the past six years. In 1991 there were 2044 cases reported (rate 7.6 per 100 000). TB mortality rates have been constant between 0.4 and 0.6 (per 100 000) since 1980. By population groups, cases have remained fairly constant among native Canadians (i.e., Indians and Eskimos) and the foreign-born, while they have regularly decreased among non-native Canadians. The foreign-born constituted 48% of all cases in 1989, and natives 20%. Japan. Japan is epidemiologically similar to those European countries, like Germany, that are still experiencing a regular decline of tuberculosis cases. In 1991 there were 50 612 cases (rate 40.8 per 100 000). The downward trend of TB notifications continues in Japan, with an average decline of 3.5% per year between 1980 and 1991. This decline, however, is smaller than that during 1962-80. Smear-positive cases have regularly increased since 1980. In general, mortality rates have been decreasing at about 4.6% per year since 1980. The TB mortality rate has decreased from 3.0 per 100 000 in 1990 compared to 2.7 in 1991. There has been no increase by age groups, although the rate of decline is slowing down in adults. No impact of the HIV epidemic on TB has been noted. Conclusion While TB continues to decrease in Belgium, Finland, France, Germany, Japan and Portugal, increases have been seen in the Scandinavian countries, Netherlands, Switzerland and the USA. A levelling-off is evident in all the other industrialized countries. The increase in TB in many industrialized countries is mainly due to two factors: rise in TB incidence among the foreign-born and the HIV epidemic. However, the latter seems to have had an impact only in the USA and in certain cities of western Europe. It is still possible to reduce TB in industrialized countries, provided that immediate steps are taken on a number of fronts . First, attempts should be made to control the disease among immigrants. Second, measures should be implemented to reduce the TB incidence among HIV-infected people. Third, the TB surveillance systems of different nations must be coordinated. And fmally, industrialized nations must address the much more severe TB epidemic faced by developing countries, as the global spread of this highly contagious disease directly relates to their own TB situation. The longer industrialized nations wait to fight the TB crisis, the more costly the epidemic will be later, in terms of both public health budgets and human lives. • Or Hans Rieder is Chief of the tuberculosis activities for the International Union against Tuberculosis and Lung Disease, 68 boulevard Saint-Michel, 75006 Paris , France. Or Moria Raviglione is with the Research and Development Unit of the Tuberculosis Programme, World Health Organization, I 2 I I Geneva 27. Switzerland