ABSTRACT
This study was performed in order to determine the frequency of antibodies to enzootic bovine leukosis (EBL), and the main factors related to the infection in dairy herds of Maranhão State, Brazil. Serum samples from 920 animals were submitted to the agar gel immunodifusion technique. The study was carried out on 92 dairy properties, in 23 districts located in the regions of Açailândia, Bacabal, São Luis Island, Imperatriz and Pedreiras. An epidemiological questionnaire was applied for each herd to investigate variables that could be associated with this infection. Of the 920 serum samples examined, 53.8% were reagent. The frequency breakdown by region was 63.50%, 61.87%, 60.62%, 41.18% and 30.83%, for Bacabal, São Luis Island, Pedreiras, Imperatriz and Açailândia, respectively. Reagents animals were found in the 23 districts studied, with detection of serologically positive bovines on 98.91% of the properties. Variables identified as risk factors included the repeated use of the same needle for blood sampling or vaccination, repeated use of the same obstetric glove, animal housing and absence of veterinary assistance. These risk factors presented a statistical significance (P < 0.05) associated to infection. These results indicate that enzootic bovine leukosis infection is high in dairy herds of the state of Maranhão and that factors related to livestock management were associated with the risk of EBL infection.
KEY WORDS
Epidemiology; frequency; enzootic leukosis; Maranhão
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