Visceral leishmaniasis/human immunodeficiency virus co-infection in India: the focus of two epidemics

India contributes heavily to the global burden of visceral leishmaniasis (VL, kala-azar) and human immunodeficiency virus (HIV)/AIDS. The prevalence of HIV seropositivity in VL patients at a tertiary care centre in northern India, as observed during a prospective study over a period of 2 years, is presented. Of the 104 cases of VL/post-kala-azar dermal leishmaniasis, six (5.7%) were found to be HIV positive, compared to 11 (5.5%) seropositive for HIV of 198 patients with fever due to other causes. Four of the six (67%) VL/HIV co-infected patients had a chronic/relapsing course, not responding to antileishmanial treatment. A CD4 T-cell count of < 200 mm(-3) was found in four of the five (80%) co-infected patients in whom the test was done. Although the level of HIV/VL co-infection in the present study was lower than that of Mediterranean countries, there is a trend towards rising co-infection. The VL-endemic states of India have a huge population of migrant labourers, who work in high-HIV-prevalence states. The reported increase in the prevalence of HIV in the VL-endemic, populous states of India is a cause of grave concern, and co-infection may assume epidemic proportions in the coming decade if left unchecked.