The host preferences of Chrysops silacea and C. dimidiata (Diptera: Tabanidae) in an endemic area of Loa loa in the Congo.

The analysis of 404 blood meals from Chrysops silacea and C. dimidiata which had been collected in the forests of the Chaillu mountains (People's Republic of the Congo) has demonstrated for the first time that both species also feed on non-human hosts. For both species the feeding patterns are fairly similar. However, man remains the main host in 89-90% of the cases. C. silacea and C. dimidiata took 6 and 4% respectively of their blood meals from hippopotamuses, 2 and 0% from rodents, 2 and 4% from wild ruminants, and 0.8 and 0.7% from monitor lizards. Whenever a differentiation has been made between the different members of the primates, only meals from humans but not from chimpanzees or baboons have been detected. The results may provide an explanation for the distinct barrier between the simian and human loiasis infections. They also give evidence for the ability of both vectors to travel over prolonged distances.