Cutaneous leishmaniasis in Kabul: observations on a 'prolonged epidemic'.

Cutaneous leishmaniasis cases in Kabul have increased steadily in number since the first report, in 1964. This increase is despite insecticide application in houses and intensive detection and treatment of cases. The age distribution of infection remains as it was in 1972, and approximates that of the Afghan population. There is no evidence of accumulating immunity in the population. Multiple lesions are infrequent, but commoner on older people, and tend to be located on the arms and legs rather than the head. A house-to-house survey failed to distinguish risk factors promoting infection. Clustering of lesions on individuals and in households is interpreted as being due to multiple bites from a single infected sandfly. Phlebotomus sergenti numbers were strongly correlated with rainfall in the previous winter, but not with numbers of cases or numbers of houses sprayed. It is suggested that Leishmania tropica is at the limit of its range in Kabul and only remains endemic because of the rapid turnover of people in the City.