SEROLOGICAL PREVALENCE AND EVALUATION OF RISK-FACTORS OF ENZOOTIC BOVINE LEUKOSIS IN THE SABANA DE BOGOTA REGION AND THE UBATE AND CHIQUINQUIRA VALLEYS OF COLOMBIA

The authors present the results of a study to determine the serologica l prevalence of the enzootic bovine leukosis virus among dairy cows in the Sabana de Bogota region and the Ubate and Chiquinquira Valleys, t he principal dairying areas of Colombia. Samples were taken from 919 a nimals selected at random from 420 farms in 51 municipalities, in acco rdance with a statistical sampling procedure developed previously, bas ed on the cattle census maintained by the Animal Health and Disease Co ntrol Office of the Institute Colombiano Agropecuario, and the recomme ndations for prevalence studies of the Pan American Health Organizatio n. The double gel diffusion technique with gp-51 antigen was used. Ser ological prevalence averaged 45.28% (ranging from 42.07% to 48.49%) wi th a confidence level of 95%. In addition, a survey was conducted to d etermine how much those in charge of herds knew about the disease, and to establish the incidence of certain risk factors possibly associate d with distribution of the causal agent. Data obtained from 232 comple ted questionnaires showed that only 54.6% of farms received profession al assistance. Of these, 6.6% received constant assistance, 4.4% recei ved visits every fortnight, 51.8% received monthly visits, 14% receive d visits every other month and 22.95% received occasional visits.