{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,9,12]],"date-time":"2025-09-12T18:35:47Z","timestamp":1757702147996},"reference-count":0,"publisher":"Cambridge University Press (CUP)","issue":"4","license":[{"start":{"date-parts":[[1998,4,1]],"date-time":"1998-04-01T00:00:00Z","timestamp":891388800000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/www.cambridge.org\/core\/terms"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Parasitology"],"published-print":{"date-parts":[[1998,4]]},"abstract":"<jats:p>In order to assess the prevalence of the cattle filaria <jats:italic>Onchocerca\n ochengi<\/jats:italic> \nin onchocerciasis vectors (<jats:italic>Simulium damnosum<\/jats:italic> s.l.) \nin North Cameroon, we searched for a means to morphologically identify\n its \ndeveloping larvae, which closely resemble \nthose of <jats:italic>O. volvulus<\/jats:italic>. To this end microfilariae of the 2 <jats:italic>Onchocerca<\/jats:italic>\n \nspecies were isolated from slaughter cattle in Ngaound\u00e9r\u00e9\n \nand injected into neonate <jats:italic>Simulium<\/jats:italic> species. Whereas the early\n \ndevelopmental stages (sausage stage, L2 and pre-infective \nlarva) were indistinguishable, the infective larvae (L3) of <jats:italic>O. ochengi<\/jats:italic>\n \nwere longer (median: 740 \u03bcm), more slender (diameter \n= 19\u00b73 \u03bcm = 2\u00b76% of body length) and had a relatively\n \nshorter tail (4\u00b79% of body length) than those of <jats:italic>O. volvulus<\/jats:italic>\n \n(680 \u03bcm, 20\u00b75 \u03bcm, 3\u00b70% and 5\u00b78% respectively).\n The \ntail of <jats:italic>O. ochengi<\/jats:italic> L3 was thick and rounded, whereas it was slightly\n \ntapering in <jats:italic>O. volvulus<\/jats:italic> L3. <jats:italic>O. ochengi<\/jats:italic> L3 produced by\n \nfeeding flies on infected cattle in a different area in North Cameroon\n \n(Sora Mboum) showed the same features as intrathoracically produced \n<jats:italic>O. ochengi<\/jats:italic> L3 from Ngaound\u00e9r\u00e9, but were even \nlonger (785 \u03bcm). On the basis of the differences in length, relative\n \ndiameter, length of the tail and shape of the tail, a simple \nkey for the separation of <jats:italic>O. volvulus<\/jats:italic> and <jats:italic>O. ochengi<\/jats:italic>\n L3 \nwas elaborated, and 248 L3 found in wild <jats:italic>S. damnosum<\/jats:italic> s.l. were\n \nseparated into \u2018<jats:italic>O. ochengi<\/jats:italic>\u2019 (160 L3) and \n\u2018<jats:italic>O. volvulus<\/jats:italic>\u2019 (88 L3) following this key. Sequential\n \ndot blot hybridization of each \nof the 248 larvae with a DNA probe which reacts with <jats:italic>O. ochengi<\/jats:italic>\n \nand <jats:italic>O. volvulus<\/jats:italic> but not with other <jats:italic>Onchocerca<\/jats:italic> species\n \n(pOo5\/1) and with an <jats:italic>O. volvulus<\/jats:italic>-specific DNA probe (pOv12)\n \nrevealed that the morphological identification had been \ncorrect in 86\u201391% of the cases. Only a small proportion (6\u20139%)\n of \nthe dot blots did not react with either probe. Since \nthis proportion was equal in experiments using experimentally produced\n L3 \nand in experiments using wild L3, the non-hybridization was certainly due\n \nto a loss of L3 during washing of the filters and not due to the presence\n of other unknown \nL3 species resembling <jats:italic>O. volvulus<\/jats:italic> and <jats:italic>O. ochengi<\/jats:italic>. Our\n \nstudy shows that in Cameroon it is possible to identify <jats:italic>O. volvulus<\/jats:italic>\n \nand <jats:italic>O. ochengi<\/jats:italic> infective larvae during routine fly dissections\n by morphology alone.<\/jats:p>","DOI":"10.1017\/s0031182097002321","type":"journal-article","created":{"date-parts":[[2002,7,27]],"date-time":"2002-07-27T09:30:22Z","timestamp":1027762222000},"page":"337-348","source":"Crossref","is-referenced-by-count":11,"title":["<i>Onchocerca ochengi<\/i>: morphological identification of the L3\n \nin wild <i>Simulium damnosum<\/i> s.l., verified by DNA probes"],"prefix":"10.1017","volume":"116","author":[{"given":"G.","family":"WAHL","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"J. M.","family":"SCHIBEL","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"56","published-online":{"date-parts":[[1998,4,1]]},"container-title":["Parasitology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.cambridge.org\/core\/services\/aop-cambridge-core\/content\/view\/S0031182097002321","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2019,4,6]],"date-time":"2019-04-06T14:59:52Z","timestamp":1554562792000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.cambridge.org\/core\/product\/identifier\/S0031182097002321\/type\/journal_article"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1998,4]]},"references-count":0,"journal-issue":{"issue":"4","published-print":{"date-parts":[[1998,4]]}},"alternative-id":["S0031182097002321"],"URL":"https:\/\/doi.org\/10.1017\/s0031182097002321","relation":{},"ISSN":["0031-1820","1469-8161"],"issn-type":[{"value":"0031-1820","type":"print"},{"value":"1469-8161","type":"electronic"}],"subject":[],"published":{"date-parts":[[1998,4]]}}}