A direct agglutination test for leishmaniasis.

Antigen suspensions of enzyme-treated, formalin-fixed promastigotes of three species of Leishmania (L. donovani, L. tropica, and L. braziliensis) were evaluated by using the direct agglutination test with serum samples from healthy individuals and patients with confirmed cases of visceral and cutaneous leishmaniasis. High cross-reactivity was obtained with the three antigens in tests with leishmania sera. Sera from patients with kala-azar were 61% to 96% positive when tested with all three antigens. In tests with sera from patients with American cutaneous leishmaniasis, 81% were positive with L. donovania and L. braziliensis antigen, whereas only 54% to 55% were positive with the other two antigens. Normal sera were reactive at low dilutions of 1:16 or less with L. braziliensis antigens. Normal sera tested with L. tropica antigen reacted to a titer of 128.