Urban epidemic of bubonic plague in Majunga, Madagascar: epidemiological aspects.

After an absence of 62 years, an epidemic of plague occurred in the harbour city of Majunga (Madagascar) from July 1995 to March 1996, following sporadic cases in March and May 1995. By 15 March 1996, 617 clinically suspected cases of bubonic plague had been notified. Laboratory testing was carried out for 394 individuals: 60 (15.2%) were confirmed to have bubonic plague and 48 (12.2%) were considered as presumptive cases. The incidence was significantly higher in males in all age groups and in both sexes in the 5-19 age group. Twenty-four deaths were related to plague, but early treatment with streptomycin has confirmed its effectiveness insofar as the case-farality ratio was only 8.7% among confirmed and presumptive cases admitted to hospital. The difficulty of clinically diagnosing bubonic plague was affirmed. The disease met favourable conditions through the poverty and low level of hygiene prevalent in most parts of Majunga.

[The plague in Madagascar: epidemiologic data from 1989 to 1995 and the national control program]. / La peste à Madagascar: données épidémiologiques de 1989 à 1995 et programme national de lutte.

After briefly reviewing the history and epidemiological cycle of the plague in Madagascar, we report a detailed analysis of 5,927 suspected cases of plague observed from 1989 to 1995 (average of 846 cases per year). Of those, 1,337 individuals (average of 191 cases per year) were confirmed (by isolation of Yersinia pestis) or indicated to be probable for plague (by positive smears). Since 1994, we observed an increasing number of confirmed and probable cases (252 cases in 1995). Most of the cases occurred between October and April in the central highlands, inside a geographical triangle limited by Alaotra lake, Itasy lake and the city of Fianarantsoa. Two exceptional epidemics occurred in the harbor of Majunga in 1991 and 1995. The bubonic plague was the most frequent clinical from (91.3%), with primarily an inguinal localization (67.8%). The mean case fatality rate was 19% of the confirmed or probable cases (14.8% for the bubonic form and 57.1% for the pneumonic form). The bubonic plague was significantly more frequent between the ages of 5 and 14 years, as compared to the general population, while the pneumonic plague was more frequent over 15 years of age. Males were more effected by the bubonic form, as the sex ratio (m:f) was 1.3. The national control program for plague is being strengthened to improve 1) the patient's early diagnosis and care system; 2) the measures for the prevention of epidemics; 3) the epidemiological surveillance; and 4) the studies on the biology of the plague vectors, rodents and fleas, and the agent, bacilli, in Madagascar.