Leucose enzoótica dos bovinos: soroprevalência, fatores de risco e níveis séricos de lisozima em bovinos leiteiros do Estado do Tocantins, Brasil

Abstract

The bovine enzootic leucosis (BEL) is a contagious infect disease cosmopolitan, with immune depressor potential, characterized by chronic evolution and great injuries that cause to the national cattle- breeding. The general objective of the achievement of this study was to contribute to the Bovine Leukosis Virus (BLV), realizing immune serologic essay to find dimension of the infection (serum-prevalent) and establish a parameter for evaluation of the immune condition (levels of serum lysozyme) of milky cattle breeding raised in the north region of Tocantins state. It was colleted serum samples of 38 bovine herds, totalizing 881 samples submitted to the double radial immune diffusion test of Ouchterlony in agar gel. From this universe of samples, 400 samples were divided in 2 groups. According to the immune serologic result obtained. G1 200 BLV negative samples, G2 BLV positive samples. The samples were still submitted to a simple radial immunodiffusion of Mancini to define the serum concentration of lysozyme which obtained results were statistically analyzed by t- student test. The results demonstrated that the BEL is amply disseminated in bovine herds examined (94,7% - 36/38), with a prevalence of serum antibodies anti BLV of the studied population corresponding to 37% (328/821) this is the first register of the infection in Tocantins State. The serum levels of lysozyme found G1 8,94 /ml e G2 7,05 /ml, knowing that the average difference between the two groups was 1,92 /ml, so, more elevated in the BLV negative animals than in the BLV positive ones, this revealed how significant is that difference. It can signalize an immune depression state of the immunity system. The obtained results demonstrated the large dissemination of BEL, being the influence, of risk factors in connection with a reduction of levels of lysozyme in animals BLV positives, and suggest that immune serologic tests realized, make possible the validation of an important parameter of evaluation of immune state of BLV positive bovine contributing, this way, to elucidation of immune depressor paper of bovine leucosis virus.