The prolonged epidemic of anthroponotic cutaneous leishmaniasis in Kabul, Afghanistan: 'bringing down the neighbourhood'.

In order to investigate the distribution and causes of the spread of anthroponotic cutaneous leishmaniasis (ACL) in Kabul, Afghanistan, a cross-sectional study was conducted during 1997-98 amongst 75,787 residents in the 13 central districts of the city. Using data on active lesions and scars with their times of onset, migration patterns and age of subjects, 2 independent methods were used to estimate, retrospectively, the annual incidence of ACL in recent years. Results indicated a rapid increase in incidence from 1987, peaking in 1996 when an estimated 12% of the population had active disease. Active prevalence was lowest in infants (aged < 2 years), and while risk was gender-independent in children and adolescents, active prevalence in those aged > 20 years was significantly higher amongst females than males (odds ratio [OR] = 1.51, 95% CI 1.34-1.70). About 44% of lesions were located on the head, 38% on upper limbs, 16% on lower limbs and 2% elsewhere. The relative frequency of head lesions dropped with age (P < 0.001), and amongst adults was lowest amongst males (P < 0.001), possibly due to the protective effect of a beard. Within the study population, 32% reported that they had immigrated from outside Kabul, 34% that they had been born in Kabul but had since migrated to another district of the city, and 34% that they had been born in the district of their present residence. Active prevalence amongst those born in their current district of residence was positively associated with the percentage of immigrants in their district (P = 0.027), indicating that a 1% increase in the percentage of immigrants increased the odds of an active lesion by 12% (OR = 1.12, 95% CI 1.01-1.24), but there was no association with the percentage of migrants from other districts in Kabul (P = 0.65) or with war damage (P = 0.33). As active prevalence was not significantly greater in immigrants than local Kabulis, these results support the hypothesis that the epidemic in Kabul has been maintained by a steady influx of susceptible immigrants. It is important that the new opportunities for social development that now exist in Kabul are not hampered by this unpleasant and stigmatizing disease. As population movement is clearly a contributing factor to its transmission, this threat is very real.