{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,24]],"date-time":"2026-04-24T15:46:29Z","timestamp":1777045589766,"version":"3.51.4"},"reference-count":0,"publisher":"Cambridge University Press (CUP)","issue":"5","license":[{"start":{"date-parts":[[2001,1,2]],"date-time":"2001-01-02T00:00:00Z","timestamp":978393600000},"content-version":"unspecified","delay-in-days":62,"URL":"https:\/\/www.cambridge.org\/core\/terms"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Parasitology"],"published-print":{"date-parts":[[2000,11]]},"abstract":"<jats:p>This paper describes, for the human onchocerciasis focus of southern Venezuela, the age profiles of <jats:italic>Onchocerca volvulus<\/jats:italic> \nmicrofilarial (mf) and nodule prevalence, mf intensity, and mf aggregation for the whole examined population (836 \nYanomami people) living in 20 villages, and for these communities classified according to endemicity levels (hypoendemic: \n[les     ] 20%; mesoendemic: 21\u201359%; hyperendemic: [ges     ] 60% infected). Mf prevalence and intensity increased with age, \nparticularly in the hyperendemic areas, and there were no marked differences between the sexes. The prevalence of nodules \nfollowed the same age pattern. Fifty percent mf prevalence was reached in the 15\u201319 year age-class when the population \nwas taken as a whole; nearly in the 10 to 14-year-olds for the hyperendemic level, in those aged 20\u201329 years in mesoendemic \nareas, and not reached at all in hypoendemic villages. The degree of mf aggregation was measured by the <jats:italic>k<\/jats:italic> value of the \nnegative binomial distribution and by the variance to mean ratio (<jats:italic>VMR<\/jats:italic>). The relationship between the standard deviation \n(<jats:sc>S.D.<\/jats:sc>) of mf counts and the mean mf density was also explored. These 3 indices (<jats:italic>k<\/jats:italic>, <jats:italic>VMR<\/jats:italic>, and <jats:sc>S.D.<\/jats:sc>) showed a tendency \nto increase with both mean mf load and host age. Since infection intensity and host age were themselves positively related, \nit was not possible to draw definite conclusions about age-specific changes of parasite aggregation. There was not a \nsignificant decrease of mf intensity after an earlier peak neither was there a shift towards younger ages of the maximum \nno. of mf\/mg reached as the endemicity level increased. These results are discussed in relation to detection of density \ndependence in the human host, selection of an indicator age-group for rapid epidemiological assessment (REA) methods, \nand strategies of ivermectin distribution in the Amazonian focus. It is recommended that, for the Amazonian onchocerciasis \nfocus, the indicator group for REA consists of all those aged 15 years and over.<\/jats:p>","DOI":"10.1017\/s0031182099006642","type":"journal-article","created":{"date-parts":[[2002,7,27]],"date-time":"2002-07-27T09:30:22Z","timestamp":1027762222000},"page":"513-525","source":"Crossref","is-referenced-by-count":17,"title":["Amazonian onchocerciasis: parasitological profiles by host-age, sex, and endemicity in southern Venezuela"],"prefix":"10.1017","volume":"121","author":[{"given":"S.","family":"VIVAS-MART\u00cdNEZ","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"M.-G.","family":"BAS\u00c1\u00d1EZ","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"C.","family":"BOTTO","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"S.","family":"ROJAS","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"M.","family":"GARC\u00cdA","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"M.","family":"PACHECO","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"C. F.","family":"CURTIS","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"56","published-online":{"date-parts":[[2001,1,2]]},"container-title":["Parasitology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.cambridge.org\/core\/services\/aop-cambridge-core\/content\/view\/S0031182099006642","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2019,5,8]],"date-time":"2019-05-08T16:08:17Z","timestamp":1557331697000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.cambridge.org\/core\/product\/identifier\/S0031182099006642\/type\/journal_article"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2000,11]]},"references-count":0,"journal-issue":{"issue":"5","published-print":{"date-parts":[[2000,11]]}},"alternative-id":["S0031182099006642"],"URL":"https:\/\/doi.org\/10.1017\/s0031182099006642","relation":{},"ISSN":["0031-1820","1469-8161"],"issn-type":[{"value":"0031-1820","type":"print"},{"value":"1469-8161","type":"electronic"}],"subject":[],"published":{"date-parts":[[2000,11]]}}}