Potential of a direct agglutination test (DAT) for detection of visceral leishmaniasis in a known endemic area in Sudan.

Hawata District (Kassala Province) is one of the known endemic areas for visceral leishmaniasis in Sudan. The co-endemicity with malaria, enteric fever, tuberculosis and brucellosis together with the limited medical laboratory facilities, rendered differential diagnosis of visceral leishmaniasis in this area, rather difficult. Two-hundred and three serum samples, including 49 collected from patients treated earlier as visceral leishmaniasis cases, were tested in a developed direct agglutination test (DAT). 100% concordance was found between the DAT results and the parasitological diagnosis in 40 confirmed cases. In nine unconfirmed, however highly suspected cases, the DAT results indicated visceral leishmaniasis. Significant improvements in the condition of those nine patients was observed during the therapeutic test and later on after a full course of treatment with sodium antimony gluconate (pentostam). DAT titres in the other serum samples (154), collected from patients with malaria, enteric fever, brucellosis and schistosomiasis and from endemic controls were below the cut-off titre (1:3200). Considering the low costs involved, easiness in performance and stability of the antigen, the DAT appears to possess high potential for routine application in Sudan.