Evaluation of adenosine deaminase seric activity in the diagnosis of bovine tuberculosis

Determination of seric levels of adenosine deaminase (ADA), an enzyme produced by monocytes/macrophages and lymphocytes, has been used in the diagnosis of human tuberculosis (TB). In the present study, ADA seric activity was evaluated comparatively to the comparative tuberculin test in the diagnosis of bovine tuberculosis. Two hundred fifty-six cattle were classified by origin and by the comparative tuberculin test as TB-positive animals (n = 52, from herds where the Mycobacterium bovis had previously been isolated), and TB-negative animals (n = 204, TB-free herds). The mean ADA seric value from the TB-positive group (4.45 ± 2.33 U/L) was significantly lower (p = 0.008) than that observed in sera from the TB-negative group (6.12 ± 4.47 U/L). When animals from a herd with clinical cases of enzootic bovine leukosis of TB-negative group were withdrawn from analysis, the mean ADA seric values of TB-negative group (5.12 ± 3.75 U/L) was not significantly different anymore from that of the TB-positive group (p = 0.28). There was no agreement in the diagnosis of bovine TB between comparative tuberculin test and determination of ADA seric values, using two different cutoff points, being 6.12 U/L and 15.0 U/L, (kappa = -0.086 and kappa = -0.082, respectively). In conclusion, the determination of ADA seric activity was not a good auxiliary test for bovine TB, because it was not able to distinguish between TB-positive and TB-negative animals.

A random sample survey of bovine Brucellosis in the State of Paraíba, Brazil

A serosurvey was conducted to estimate the prevalence of bovine brucellosis in the State of Paraíba, Brazil. A random sample of six municipalities was selected from each of three ecoregions of the State: the Agreste/Litoral region (1), the Cariri/Curimatau region (2) and the Sertão region (3). These 18 municipalities were divided in quadrants and one herd was selected at random from each quadrant. The sampling scheme included herds with more than 50 bovines, which excludes small-holder subsistence livestock production. At least 32 animals were sampled within each herd, stratified in four age categories, as follows: (1) at least 8 animals under 6 months of age, (2) at least 8 animals of 7 to 18 months of age, (3) at least 8 animals of 19 to 30 months of age and (4) at least 8 animals over 30 months of age. Antibodies to Brucella abortus were observed in 8 out of 18 municipalities (44.44 percent),in 8 out of 72 herds included in this study (11.11 percent) and in 8 animals out of 2343 samples collected (0.34 percent). The prevalence of test positive cattle by ecoregion/cattle production regions in the state showed no significant differences of risk among them. Likewise, there was no significant difference of risk among the different age categories studied. It was observed that brucellosis is widely spread across the state albeit with low animal prevalence. These results may be used in the design of a strategy for controlling bovine brucellosis in the State of Paraíba.

Foi realizado um estudo para a determinação da prevalência sorológica de brucelose bovina no Estado da Paraíba. Seis municípios foram selecionados aleatoriamente em cada uma das três ecorregiões do Estado: a região do Agreste/Litoral (1), a região do Cariri/Curimatau (2) e a região do Sertão (3). Estes 18 municípios foram divididos em quadrantes e uma propriedade foi selecionada em cada quadrante. Foram amostradas propriedades com mais de 50 animais, o que exclui as pequenas propriedades de subsistência. Pelo menos 32 animais foram amostrados de cada rebanho, estratificados nas quatro faixas etárias seguintes: (1) no mínimo 8 animais até 6 meses de idade, (2) no mínimo 8 animais com 7 a 18 meses de idade, (3) no mínimo 8 animais com 19 a 30 meses de idade e (4) no mínimo 8 animais com mais de 30 meses de idade. Anticorpos anti-B. abortus foram observados em 8 de 18 municípios (44,44 por cento), em 8 de 72 rebanhos (11,11 por cento) e em 8 animais dos 2343 amostrados (0,34 por cento). A análise dos resultados de prevalência por ecorregião do Estado não revelou diferença significativa de risco entre elas. A análise dos resultados por categorias de faixa etária também não evidenciaram diferença significativa de risco entre as mesmas. Foi observado que a brucelose está amplamente disseminada no estado embora com uma baixa prevalência animal. Estes resultados podem ser úteis no delineamento de estratégias de controle da brucelose bovina no estado da Paraíba.