Evaluation of a visually read ELISA for serodiagnosis and sero-epidemiological studies of kala-azar in the Baringo District, Kenya

Abstract

ELISA for detecting leishmanial antibodies was established at Baringo District Hospital Kabarnet, Kenya, and successfully applied in clinical routine and sero-epidemiological surveys. To simplify the procedure and to make it more economical, ELISA was read as visual endpoint titre and blood was collected by the blotting paper method. 63 parasitologically confirmed kala-azar patients all showed a diagnostic IgG specific ELISA titre of 1:27,000 or more, which indicates a sensitivity of 100%. 11 of 14 persons found with this diagnostic titre during a house-to-house survey in a known focus of kala-azar could be confirmed parasitologically. Two more showed typical signs and symptoms of kala-azar and were successfully treated accordingly. Controls from unaffected areas were all negative. Low titres of 1:1000 and 1:3000 were observed in healthy individuals from foci of kala-azar, but could be easily distinguished from active cases. ELISA has been shown to be a convenient and reliable method for the serodiagnosis of East African kala-azar. The technique can be integrated into the routine work of a clinical laboratory at the level of a district hospital, without sophisticated equipment and with a minimum of funds. Blood of suspected kala-azar cases can be collected on blotting paper in dispensaries and health centres near known foci and sent to the laboratory.