Investigation of the spread of human visceral leishmaniasis in central Tunisia.

The epidemiology, clinical patterns, and spatial spread of Mediterranean visceral leishmaniasis were retrospectively studied in central Tunisia. The clinical profile of the disease was typical of the Mediterranean infantile form. Malnutrition and associated infectious diseases were observed in 62.5% and 55% of cases, respectively. The case-fatality rate was 6.2% and resistance to meglumine antimonate was observed in 1.6% of patients. The annual incidence of cases increased from approximately 10 cases per year before 1991 to approximately 50 cases per year between 1992 and 1994. The cumulative incidence was 133.7/100,000 among children aged < 15 years. This increase was preceded by 3 years of high mean annual rainfall in the region. The spatial distribution of the incidence of the infection through time showed an aggregation of cases in the northern part of the area where intensive agriculture projects took place during the last 10 years, leading to the establishment of a stable Leishmania infantum transmission cycle below the Atlas mountain chains, and an evident tendency to a progressive extension to the south.