[The plague in Madagascar: epidemiologic data from 1989 to 1995 and the national control program]

Abstract

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.