After the widespread 1967–68 epizoodemic of Venezuelan equine encephalomyelitis (VEE) in areas of low and moderate seasonal rainfall in Colombia, a strain of VEE virus was sought in the high-rainfall region of the Pacific lowlands where previous serological studies had shown past activity of VEE virus in man without indication of overt clinical illness in epidemic form. A total of 20 sentinel hamsters, in two groups, were exposed for 2-week periods, one in July and one in August and September 1969, along the margins of a grass-overgrown, freshwater swampy area 50 km inland from the port of Tumaco near the Ecuadorian border. One hamster yielded VEE virus and two others yielded Eastern equine encephalomyelitis (EEE) virus. Virus was not isolated from 7,199 mosquitoes captured in the vicinity of the exposed hamsters. This isolation of VEE virus confirms the suspected presence of the agent in the Pacific lowlands of Colombia and also the utility of sentinel hamsters for detecting endemic VEE virus activity in the American Tropics. The isolations of EEE virus are the first from Colombia, the first from the west coast of South America, and the first from sentinel hamsters.
Staff member, The Rockefeller Foundation.
The Sección de Virus receives support in part from The Rockefeller Foundation and from the Tulane University International Center for Medical Research and Training, Grant TW-00143 from the National Institute of Allergy and Infectious Diseases, National Institutes of Health, U. S. Public Health Service, Bethesda, Maryland 20012.