{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,20]],"date-time":"2026-09-20T01:23:03Z","timestamp":1789867383002,"version":"4.0.1"},"reference-count":0,"publisher":"American Society of Tropical Medicine and Hygiene","issue":"3","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Am J Trop Med Hyg"],"published-print":{"date-parts":[[1999,3]]},"abstract":"<jats:p>Epizootics of Venezuelan equine encephalitis (VEE) involving subtype IAB viruses occurred sporadically in South, Central and North America from 1938 to 1973. Incompletely inactivated vaccines have long been suspected as a source of the later epizootics. We tested this hypothesis by sequencing the PE2 glycoprotein precursor (1,677 nucleotides) or 26S\/nonstructural protein 4 (nsP4) genome regions (4,490 nucleotides) for isolates representing most major outbreaks. Two distinct IAB genotypes were identified: 1) 1940s Peruvian strains and 2) 1938-1973 isolates from South, Central, and North America. Nucleotide sequences of these two genotypes differed by 1.1%, while the latter group showed only 0.6% sequence diversity. Early VEE virus IAB strains that were used for inactivated vaccine preparation had sequences identical to those predicted by phylogenetic analyses to be ancestors of the 1960s-1970s outbreaks. These data support the hypothesis of a vaccine origin for many VEE outbreaks. However, continuous, cryptic circulation of IAB viruses cannot be ruled out as a source of epizootic emergence.<\/jats:p>","DOI":"10.4269\/ajtmh.1999.60.441","type":"journal-article","created":{"date-parts":[[2017,5,10]],"date-time":"2017-05-10T17:08:32Z","timestamp":1494436112000},"page":"441-448","source":"Crossref","is-referenced-by-count":65,"title":["Genetic evidence for the origins of Venezuelan equine encephalitis virus subtype IAB outbreaks."],"prefix":"10.4269","volume":"60","author":[{"given":"S C","family":"Weaver","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"M","family":"Pfeffer","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"K","family":"Marriott","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"W","family":"Kang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"R M","family":"Kinney","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"2795","container-title":["The American journal of tropical medicine and hygiene"],"original-title":[],"link":[{"URL":"https:\/\/www.ajtmh.org\/view\/journals\/tpmd\/60\/3\/article-p441.xml","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.ajtmh.org\/downloadpdf\/journals\/tpmd\/60\/3\/article-p441.xml","content-type":"text\/html","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/www.ajtmh.org\/downloadpdf\/journals\/tpmd\/60\/3\/article-p441.xml","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,9,4]],"date-time":"2024-09-04T10:52:34Z","timestamp":1725447154000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.ajtmh.org\/view\/journals\/tpmd\/60\/3\/article-p441.xml"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1999,3]]},"references-count":0,"journal-issue":{"issue":"3"},"URL":"https:\/\/doi.org\/10.4269\/ajtmh.1999.60.441","relation":{},"ISSN":["0002-9637"],"issn-type":[{"value":"0002-9637","type":"print"}],"subject":[],"published":{"date-parts":[[1999,3]]}}}