Persistence of human leishmanial antibodies in an endemic area of visceral leishmaniasis in El Agamy, Egypt.

In an endemic area of visceral leishmaniasis (VL), individuals with leishmanial antibodies that reacted in the radioimmunoassay (RIA) were retested to determine duration of leishmanial antibody retention. One fourth of adults retained antibodies for at least 10 months. At least 2/3 of asymptomatic children retained leishmanial antibodies for 5 to 7 months after detection. 2/3 of children treated for VL retained leishmanial antibodies for 5 to 7 months after treatment, while 1/3 retained antibodies for over a year. These data modify conclusions that can be drawn from a single serosurvey. Since leishmanial RIA antibodies can persist in humans for at least two transmission seasons, incidence estimates require serial serosurveys.