Kala-Azar in a high transmission focus: An ethnic and geographic dimension

In 1994-1996, we studied a group of 58 game wardens stationed in an area kn own to be highly endemic for visceral leishmaniasis (kala-azar) for evidenc e of infection with Leishimania donovani. Leishmania DNA was detected by th e polymerase chain reaction in the peripheral blood of cases of active kala -azar, former patients with visceral leishmaniasis, patients, and asymptoma tic subjects. Using the cloned antigen rk39, antibodies were detected in 44 .2% of the game wardens while leishmanin skin test result was positive in 7 7% of our sample. It was shown that certain tribes from northern Sudan were more likely to develop subclinical infections, while those of the Baria tr ibe from southern Sudan and those of the Nuba tribe from western Sudan were more likely to develop visceral leishmaniasis. Whether this is due to gene tic factors or previous exposure to Leishmania parasites remains to be eluc idated.