Assessments of the transmission of Onchocerca volvulus by Simulium sanctipauli in the Upper Denkyira District, Ghana, and the intermittent disappearance of the vector

摘要: Following studies on the transmission of Onchocerca volvulus (Leuckart) by Simulium sanctipauli Vajime & Dunbar (Diptera, Simuliidae) in Upper Denkyira District Ghana 2001 and 2002 (Kutin et al., Med Vet Ent 18:167-173, 2004), further assessments were carried out 2006 2013/2014 to determine whether parameters had changed since community-directed ivermectin treatment (CDTI) began 1999. There no marked changes intensities 2006. Only slight, but non-significant, reductions observed infection rates parous flies with larval stages (L1-L3) O. from 44.1 % (of 1672 flies) 2001/2002 42.1 (506) 6.5 5.9 carrying infective larvae their heads. This suggested that there was an ongoing area parasite reservoir human population still high. Unexpectedly, conducted October 2013 March 2014 revealed vector S. apparently disappeared ceased, probably as a result intensified gold mining activities along rivers Ofin Pra. The water both extremely turbid, heavily loaded suspended solids, preventing development blackfly larvae. Some breeding biting yahense small tributary Pra, Okumayemfuo, which is not affected mining. However, rate low, only 3.7 163 infected first stage (L1) volvulus.