The performance of direct agglutination tests (DAT) in the diagnosis of visceral leishmaniasis among Ethiopian patients with HIV co-infection.

The incidence of visceral leishmaniasis (VL) in Ethiopia has dramatically increased over the last 10 years, coinciding with the advent of the HIV epidemic. HIV co-infection in VL patients results in atypical, clinical and serological presentations, and may hamper serological diagnosis of VL. The performance of direct agglutination tests (DAT) in the diagnosis of VL in 103 Ethiopian patients with or without HIV infection was therefore investigated. The DAT results indicated that 96 of the patients had leishmanial infections, although amastigotes were only detected in samples from 91. Data on HIV status showed that 50.7% of all patients but 56.0% of the parasitologically confirmed cases of VL patients were HIV-positive. Based on the 95 patients who were each examined both by DAT and parasitological methods, the overall sensitivity of the DAT was 97.7%. Among the parasitologically confirmed cases of VL, a false-negative DAT result was obtained for two (3.9%) of the 51 cases who had HIV co-infection and for none of the 40 HIV-negative cases. In contrast to the observations made in Europe, DAT in Ethiopia therefore remain reasonably sensitive in the diagnosis of VL during HIV co-infection. The results are discussed in view of the possibility of distinctive antibody responses induced by Leishmania donovani donovani and L. d. infantum in HIV-infected patients.