STUDIES ON THE PREVALENCE OF LEISHMANIN SKIN-TEST POSITIVITY IN THE BARINGO DISTRICT, RIFT-VALLEY, KENYA

The leishmanin skin test (LST) was applied in 26 clusters of an averag e of 97 individuals in Baringo District, Kenya. These clusters were ce ntered around recent cases of visceral leishmaniasis (VL). Of 2,411 in dividuals tested, 254 (10.5%, 155 males and 99 females) had a positive reaction. Among cured VL patients, the frequency was approximately 30 % and no sex difference was observed. In the population as a whole, LS T positivity increased with age to a stable level from approximately 1 5 years of age, reflecting an endemic situation. The level of LST posi tivity was 25-30% and 10-15% in males and females, respectively. Uninf ected household contacts of VL cases had a higher frequency of LST rea ctivity than the rest of the population. This relationship was signifi cant only in females and children, the prevalence ratio being 2.3 (95% confidence interval 1.3-4.1), 1.9 (1.1-3.5), and 1.4 (0.8-2.5) for fe males, children, and males, respectively. The frequency of LST positiv ity was higher individuals living in wood houses than in individuals l iving in house with mud or stone walls. Again, this difference was sig nificant only in females and children (P = 0.02 and P = 0.04), but not in males (P = 0.7). The results suggest that children and women are e xposed to the parasite in or around their houses, whereas adult males are, in addition, exposed elsewhere.