Development by injection in Simulium damnosums.l. of two Onchocercaspecies from the wart hog to infective larvae resembling type d larvae (Duke, 1967)

Four wart hogs (Phacochoerus aethiopicus) examined in the Sudan savanna of North-Cameroon were all found infected with two types of skin microfilariae. One was O. ramachandriniBain, Wahl and Renz, 1993, the adult worms of which live in the subcutaneous tissues of the feet. The other, smaller type belongs to a new Onchocercaspecies, the adult worms of which were not yet found. O. ramachandrini-microfilariae were evenly distributed across the whole body surface, those of Onchocercasp. were concentrated on the back. The two species of microfilariae were isolated from an infected hide, separated under the dissecting microscope and injected into the thorax of pupae-hatched S. squamosumand S. damnosums. str. females. Both filariae developed in both flies at high rates (33 - 47% of injected microfilariae) and without pathological forms to infective larvae (L3). Both L3-species had a caudal tip, were long, slender and very motile and had a conspicuous glandular oesophagus. L3 from O. ramachandrini- microfilariae had a long glandular oesophagus (55 % of total L3 length), a round head and measured an average of 955 μm long and 19.2 μm wide. L3 from the other microfilaria-species were shorter (845 μm, P‹ 0.00 1) and thinner (16.7 μm, P‹0.001) and had a shorter glandular oesophagus (36%, P‹0.001), a shorter tail (P‹0.01) and a conical head.