Visceral leishmaniasis in Somalia. Circulating antibodies as measured by DAT, immunofluorescence and ELISA.

Abstract

Sera from patients with visceral leishmaniasis (VL) (n = 26), healthy residents of Mogadishu (n = 157), inhabitants of a village in an endemic area (n = 276) and healthy Swedes (n = 60) were examined using the direct agglutination test (DAT), immunofluorescence (IF) and ELISA for antibodies against Leishmania donovani. The study was carried out in order to provide baseline data for antibody responses in visceral leishmaniasis as existing in Somalia and to explore which one of these methods would be most suitable for diagnosis of clinical cases as well as for epidemiological population studies in Somalia. All patients had high levels of circulating antibodies, however, lower values were recorded in the early stages of the disease. High reactivity in ELISA was seen first after one year. All three tests distinguished well between sera from VL patients and healthy controls. Approximately 10% of the sera from villagers were reactive above the cut-off levels in the three tests. DAT is the simplest to perform and does not require much equipment. ELISA can be made simple and economic if performed in one serum dilution and read visually. IF requires more expensive and specialized equipment and is not suitable for large scale examination of sera. A complete evaluation of the three tests should also include the analysis of sera from various stages and manifestations of the disease.