Infective larvae of fiveOnchocercaspecies from experimentally infectedSimuliumspecies in an area of zoonotic onchocerciasis in Japan

Genetic evidence for the presence of two species ofOnchocercafrom the wild boar in Japan

“…The longer Onchocerca-like microfilariae (about 1.5 times the length of O. dewittei japonica) found in wild boar were provisionally referred to Onchocerca sp. in our recent study (Fukuda et al, 2008). The CO1 gene analysis of adult O. dewittei japonica confirmed that the short microfilariae from wild boar corresponded with this species.…”

“…In all the Japanese cases, the infections were caused by Onchocerca dewittei japonica Uni, Bain & Takaoka, 2001, a common filarial parasite of wild boar Sus scrofa Linnaeus, 1758, in Japan (Takaoka et al, 2001;Uni et al, 2001), but the life cycle of which was unknown. Recently we have proved experimentally that six local black-fly species are suitable for the development of O. dewittei japonica microfilariae to the infective (third stage) larva, suggesting that Simulium species are vectors of the parasite (Fukuda et al, 2008). During this investigation, we also found microfilariae of a species of Onchocerca (longer than those of O. dewittei japonica) from wild boar and demonstrated the complete larval development of this unnamed Onchocerca sp.…”

“…In addition, we presumed that type II infective larva might be O. gutturosa of cattle, O. dewittei japonica, or the unnamed Onchocerca sp. of wild boar on the basis of the morphometric observation of experimentally produced infective larvae (Fukuda et al, 2008). The present study shows that morphologically similar infective larvae of these three Onchocerca species are clearly distinguishable by comparison of their CO1 gene sequences.…”

“…sp.) were recovered from the black flies experimentally infected in our previous study (Fukuda et al, 2008 (QIAGEN, Hilden, Germany). The final volume of each extract was 50-100 µl.…”

“…Although the adult was unknown, this filaria was tentatively assumed to be a distinct species. Interestingly, the infective larvae of these two Onchocerca species are morphologically indistinguishable (Fukuda et al, 2008). To determine the natural vectors of O. dewittei japonica, accurate identification of the infective larvae of zoonotic Onchocerca species from wild-caught black flies is needed.…”