Effect of attraction factors on the sampling of Chrysops silacea and C. dimidiata (Diptera : Tabanidae), vectors of Loa loa (Filaroidae : Onchocercidae) filariasis

The effects of fire and human host density on #Chrysops silacea and #C. dimidiata abundance and age structure was evaluated at sites of #Loa loa filariasis transmission in the Congo rain forest. Fire increased the catch of #C. silacea 8.5-fold at ground level and 5-fold in the canopy, but did not modify the catch size of #C. dimidiata. Catch size increased 2-fold when a pygmy camp located near the collecting station was inhabited. The presence of fire did not alter the parity and #Loa loa infection rates in the populations. (Résumé d'auteur

Chrysops silacea and C. dimidiata : fly densities and infection rates with Loa loa in the Chaillu mountains, Congo Republic

The densities, infection rates with #Loa loa, and parous rates of #Chrysops silacea and #C. dimidiata were studied in various ecological zones throughout the Chaillu mountains in the People's Republic of the Congo. In the rainy season, #C. dimidiata was the major vector in the forest, whereas #C. silacea was predominant in the cleared forest zones. Fly densities were higher in the forest (natural forest or palm-grove) than in the villages. Parous and infection rates varied according to the ecological zone. The infection rate of parous females was related to the microfilarial rate in the human population, indicating that the #Chrysops populations were extremely stable in the rainy season. (Résumé d'auteur