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A major study was conducted to determine the prevalence of Bancroftian filariasis in 9 health districts located mainly on the east and north coast of Madagascar between 1995 and 1997. The study population included 2524 people 10 years or older. On the east and north coast, the incidence of microfilarial carriers varied depending on location from 7 p. 100 to 47 p. 100 in men and 3 p. 100 to 33 p. 100 in women. The highest incidences, i.e., around 33 p. 100 in both sexes, were observed in the southeastern districts of Ifanadiana, Manakara, and Vangaindrano. In the other districts on the east coast, the highest rates occurred mainly in men, i.e., 47 p. 100 in Vavatenina, 33 p. 100 in East Feneriva, and 33 p. 100 in Mahanoro. Only two districts on the west coast were studied, i.e., Marovoay where the incidence was zero and Ankazoabo where the prevalence was 4 p. 100 for men and 3 p. 100 for women. The results are compared with those of a study carried out in 1958. At 16.22 p. 100, chronic morbidity is relatively common in men but less disabling, i.e. mainly scrotal and member elephantiasis and hydroceles. Chronic morbidity was only 2.26 p. 100 in women, i.e. mainly member elephantiasis. Control of Bancroftian filariasis may be achievable by targeted use of drug prophylaxis and bednets in zones of high prevalence.

We conducted a 5-year (1989-1993) retrospective analysis on a series of patients screened and treated for tuberculosis in order to determine the epidemiological aspects of the disease in mid-western Madagascar. Pulmonary forms affected 97% of patients, and predominantly men (sex ratio: 1.4); 83% of patients with pulmonary tuberculosis were coughing up acido-alcoholo-resitant bacilli. Haemoptysis and general deterioration, the most frequently met pathological signs, were observed respectively in 62% and 24% of cases. This explains the high rate of hospitalisation (42%), especially for patients with difficult access to services. Significantly, in terms of socio-professional category, live-stock breeders and farmers represented 32% of notified cases, and cattle-traders 18%. We draw attention to the possible role played by Mycobacterium bovis in human case-findings in a region characterised by cattle-breeding.

In 1996 and 1997, a knowledge, attitude and practice survey concerning seafood poisonings was conducted in 560 villages spread along the Madagascar coasts, gathering 585,000 people. 175 serious and 205 mild seafood poisonings after fish, shark and turtle meals occured during the period 1930 to 1996. Squales (mainly Sphyrnidae and Cacharinidae familiesi) are the most often responsible of serious poisoning (48% of episodes), then other fishes (37%), and mainly of the Clupeidae family (herrings, sardinels), then marine turtles (11%), with Eretmochelys imbricata and Chelonia mydas, and finally crabs (4%). Neurological symptoms are predominant in squale poisonings, neurological symptoms associated with gastrointestinal symptoms are present in 50% of all kind of seafood poisoning episods. Most of episods incame on the East Coast (mainly Toamasina and Antisiranana Region) and on the South-West Coast (Toliara Region). Mild seafood poisonings are spread along all the Coasts but central East Coast; fishes are the most often responsible (41% of episodes). Gastro-intestinal symptoms are the most conmon. More than 50% of t interviewed people knows about poisoning risks with some kind of marine animals, but less than 20% practice preventive measures such as giving a piece of fished animal to a domestic animal before eating. These results are used to plan a comprehensive epidemiological surveillance and control programme.

In June and July 1996, a knowledge, attitude and practice survey concerning seafood poisonings was conducted in Tuléar Province, 41 villages spread along 300 km of cost, with some 34,000 inhabitants, were included in the survey. 84 seafood poisonings after fish, shark and turtle meals occurred during the period 1931 to 1995; 14 of them were responsible of deaths. The family of toxic fishes are Clupeidae, Tetraodontidae, Scaridae and Siganidae. Sphyrna lewini is the shark species the most often responsible for poisonings. Three turtle species are involved in poisonings: Eretmochelys imbricata, Chelonia mydas and Dermochelys coriacea. Clinical patterns were related to marine toxins. Although the communities were aware of the risks, there was no change in seafood meal practice. Preventive measures are not very often used. Practical techniques to detect toxins, although very simple, are not systematically carried out. For a better understanding of the seafood poisoning risk in Madagascar, a retrospective survey in the villages located in coastal areas all around Madagascar was to be carried out in 1997. An eco-toxicological survey will likewise probably be organised in an Indian Ocean regional approach.

After a thirty year period of successful control, bubonic plague showed the first signs of return in Madagascar where a fatal outbreak occurred in Antananarivo in 1978. A second outbreak was observed in Mahajanga in 1991 after more than a half century. In 1997, 459 confirmed or presumptive cases were reported, as compared to 150 to 250 cases during the last years. However the actual extent of this recrudescence must be placed in the perspective of a more efficient control program that has led to better reporting of suspected cases and availability of more accurate diagnostic techniques. Recent research has led to the development of highly effective immunological diagnostic tools (detection of antibodies and F1 antigen) allowing not only better surveillance of the disease in man and animals but also renewed study of the epidemiological cycle in the current environment. In this regard the capacity of several endemic fleas as vectors and the role of the rat Rattus norvegicus and the musk shrew Suncus murinus are currently under investigation. Genetic study of strains collected from 1936 to 1996 has demonstrated the appearance of 3 new ribotypes of Yersinia pestis since 1982 in the zones of strongest plague activity in Madagascar. A strain showing multiresistance to standard therapeutic antibiotic agents was isolated in 1995. Bubonic plaque is a priority health problem in Madagascar but remains a major concern for the rest of the world.

Human cases of plague, which had virtually disappeared in Madagascar after the 1930s, reappeared in 1990 with more than 200 confirmed or presumptive cases reported each year since. In the port of Mahajanga, plague has been reintroduced, and epidemics occur every year. In Antananarivo, the capital, the number of new cases has increased, and many rodents are infected with Yersinia pestis. Despite surveillance for the sensitivity of Y. pestis and fleas to drugs and insecticides and control measures to prevent the spread of sporadic cases, the elimination of plague has been difficult because the host and reservoir of the bacillus, Rattus rattus, is both a domestic and a sylvatic rat.

The HIV seroprevalence per 100,000 adults Malagasy rose from 20 in 1989, to 30 in 1992, and to 70 in 1995. In that year, the total number of HIV infected people in the Big Island was estimated at 5,000, the number of people sick with AIDS at 130, and the people at risk at more than 1,000,000. The latter are the persons infected with other STDs and individuals (or their partners) with risky sexual behaviour (e.g. numerous sexual partners, occasional sexual partners, and/or sexual contacts with commercial sex workers). The HIV prevalence rate is low as compared with those of other countries. Nevertheless, the spread of the HIV infection is alarming in some parts of the country and the risk factors are also present, namely: the high prevalence of STDs, numerous sexual partners, the low use of condoms in all groups, the development of tourism, the development of prostitution associated with social and economical problems, and internal and international migrations (with risky sexual contacts). Therefore, the still low but rising HIV prevalence in 1995 does not warrant complacency. To estimate the trend of HIV prevalence within the population, it is useful to know two different assumptions, as follows: firstly, a controlled evolution of the epidemic (low epidemic) and secondly, a very fast spread of the epidemic (high epidemic). If we consider the 5,000 individuals seropositive in July 1995, the Aids Impact Model (AIM) projection model shows that HIV seroprevalence rates among adults in 2015 might be between 3% (when the progression course of HIV epidemic is low) and 15% (when the progression course of HIV epidemic is high). By 2015 AIDS could have severe demographic, social, and economic impacts. Then, it is necessary to take measures to prevent contamination. Five major interventions are required: public information about AIDS, HIV transmission mechanism, and its prevention, communities education via the respected people and the notabilities to promote moral values, reduce the number of sexual partners, delay visit of sexual activity, and advice for infected couples; screening of blood donors and the supposed high risk group; control of STDs; reduction of the number of sexual partners; promotion of condom use, abstinence, and fidelity. To sum up, the fight against AIDS is not only the health professional workers' problem. It concerns all Malagasy people. Therefore, successfullness in prevention efforts to slow the epidemic needs concerted, collective, and long lasting actions from all sectors of the society for the nation's future and the well-being of the rising generations.

If seafood poisonings are well documented in the Pacific region, they are not often reported in the Indian Ocean. In Madagascar, fishermen and people living in coastal areas are traditionally aware of seafood poisonings. Mass intoxications were described in the sixties, including lethal cases following sardine ingestion. From 1989 to 1993, 28 ichtyosarcotoxism cases, mainly ciguatera occurring in children, were reported in Tulear hospital. From July 1993 to May 1996, nine seafood poisoning outbreaks occurred in coastal villages after turtle, shark and sardine meals. Clinical symptoms were related to marine toxins. For turtle intoxications, gastro-intestinal symptoms are the most frequently seen (acute stomatitis, dysphagia, vomiting and diarrhea), with case fatality rates around 7%. For shark intoxications, the most frequent symptoms were neurologic (paresthesia specially peribuccal and extremities), and gastro-intestinal (diarrhea and vomiting), with specific case fatality rates varying from 0% to 30%. For sardine intoxication, symptoms were gastro-intestinal (vomiting) and neurologic (paresthesia), and from the two intoxicated people one died. Two previously unknown biotoxins were isolated from the liver of a shark responsible for a mass poisoning, namely carchatoxins. For the turtles, the search of chelonitoxin is under way. For the sardines, clupeotoxin was isolated. Because of the frequency and the gravity of collective seafood poisonings occurring in recent years, the Ministry of Health has implemented a Seafood Poisoning National Control Programme. This programme is based on three major strategies: the setting of an epidemiological surveillance network, the prevention of the communities through educational programmes, and the development of research on marine eco-environment.

The authors reported the results of paludometric and entomological studies carried-out for two years: 1995-1996 in two localities: Ampanihy and Ankilimivory located in the South of Madagascar. These studies followed a suspect malaria epidemic in Ankilimivory in June and July 1994; the population plasmodic index was of 45%. In April 1995, this data was of 35% in Ampanihy and of 15% in Ankilimivory. Entomological studies carried out in April 1996 allowed to find Anopheles funestus in Ankilimivory and Anopheles gambiae l. s. in the two localities. Both the endemicity of malaria and the role of A. funestus had to be taken into account in the southern part of Madagascar. Until now, rare epidemics in this area were thought to occur only when climatic conditions were favorable, mainly during the rainy season. However, other factors, linked with the development could also facilitate the upset of epidemics, e.g.: irrigation programmes.