Abstract

VALERO, Nereida et al. Post- vaccination antibody titles in equines vaccinated with TC83 strain of the Venezuelan equine encephalitis virus. Rev. Cient. (Maracaibo) [online]. 2007, vol.17, n.1, pp.15-20. ISSN 0798-2259.

As a result of the last Venezuelan equine encephalitis epizoodemic (VEE), happened in Venezuela during 1995 that affected equidae and humans of Zulia State and another states of the country, the reinforcement of epidemiological surveillance programs for the prevention and control of equine encephalitis was stablished. As an efficient measure, the new cycles implementation of systematic equine immunization in the risk areas was taken. In order to evaluate the duration of the immunity with a TC-83 strain attenuated virus vaccine, used in the vaccination program, 662 equidae sera samples, vaccinated at different times (194 with two years, 412 with a year and 56 with 6 months postvaccinated) without disease precedents and from different municipalities of Zulia State, Venezuela, were analyzed through an immune enzymatic assay (ELISA) to determine IgG anti VEE antibodies titles. A 39.8% (164/412) of positive sera in one year postvaccinated animals was detected, from which 60.2% do not showed antibodies titles. Furthemore, a 95.9% (186/194) equidae with two years postvaccinated without immunity to anti-VEE were detected. From the 56 equidae with 6 months postvaccinated, 48 (87.7%) showed high antibodies titles. The results demonstrated a lack of anti-VEE immunity, suggesting a prompt revision of the vaccination program specifically related to the evaluation of the antigenic’s activity length time and/or possible faults in its application

Keywords : Venezuela equine encephalitis; immunity; vaccine; equidaes.