SEROPREVALENCE AND RISK FACTORS OF INFECTION BY BOVINE LEUKOSIS VIRUS IN DAIRY HERDS IN NORTHERN TOCANTINS STATE, BRAZIL

C.H.C. Fernandes L.E.H. de Melo T.G. da S. Tenório E.I. Mendes A.C. de C. Fernandes T.R.R. Ramalho P.A. Moura Sobrinho R.A. Mota About the authors

ABSTRACT

Enzootic bovine leukosis (EBL) is a cosmopolitan retrovirosis that progressively spreads in herds causing great damage to Brazilian livestock. The aim of this study was to determine the seroprevalence of EBL and to research risk factors associated to the positive serology. For this purpose, 881 serum samples, collected from 38 dairy herds raised in northern Tocantins State, were examined by the agargel immunodiffusion test (AGID-EBL) for detection of specific anti-BLV antibodies. The AGIDEBL test showed a prevalence of 37% (326/881), with confidence interval from 32.8% to 41.2%. Among the analyzed risk factors, the milking system used on the properties presented significant correlation (p < 0.05) with the prevalence of EBL. The seropositivity observed in the greater part of the examined herds, exhibiting the expressive spreading of the BEL, suggests a connection between the number of seropositive animals and the spread of the dairy livestock in northern Tocantins State, Brazil.

KEY WORDS
Enzootic bovine leukosis; prevalence; bovine; risk factors

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