Utilização de teste cervical comparativo frente a um ensaio imunoenzimático (ELISA) para diagnóstico de tuberculose em bovinos da raça nelore.

Abstract

Bovine tuberculosis is a zoonotic disease of worlwide occurrencei. This disease is difficult to control, mainly due to the lack of a diagnostic test to detect sick animals at all stages of infection. Through the comparison between the multiplex ELISA test and cervical comparative test for thediagnosis of tuberculosis in cattle, this study aimed to evaluate the response of the ELISA or cervical comparative test to determine the occurrence of infection in herds in northeastern Pará and to evaluate the efficacy of the methods by comparing the results obtained. Were used 400 Nelore cattle, raised on five farms (Castanhal, São Francisco do Pará, Garrafão do Norte, Santa Isabel do Pará and Capitão Poço), one farm in each city. these are distributed as follows: in the middle region of northeastern Pará municipalities of Captain Wells and Carboy North Guamá located in the city of São Francisco do Pará in Bragantina microregion, and meptropolitan of Belém municipalities Castanhal and Santa Izabel belonging to microregion of Castanhal. The animals were subjected to comparative cervical test, following the standards proposed by the National Program for the Control and Eradication of Animals Brucellosis and Tuberculosis - PNCEBT. On the day of inoculation of purified protein derivative, blood samples were collected from the animals, and after centrifugation to obtain serum, carry out the IDEXX ELISA imununcassay M. bovis, following the protocol standardized by the manufacturer. Descriptive statistics of the data was represented by the frequency (%) of animals positive or negative, both among such test (ELISA and comparative cervical test) and between different farms ( 1, 2, 3, 4 e 5). In the experiment conducted at Farm 1 and 2, only 1 of 80 animals subjected to cervical comparative test showed positive results. The others showed up negative for M. bovis infection. Already at farms 3, 4 and 5, all animals were negative for the same test. Diagnosis by IDEXX ELISA M. Bovis identified 5,5% (22/400) of animals positive for tuberculosis. Farm 1 were dianosed 8,75% (7/80), at Farm 2, 10% (8/80) of the animal examined were positive, the Farm 3, 6,25% (5/80) of cattle examined were positive. Farms 4 or 5 presented only one positive case each, with 1,25%. According to the data obtained in this study could be inferred that bovine tuberculosis is a disease present in the regions of northeastern Pará, Belém metropolitan, low Amazonas, Southeastern Pará and Southwest. This fact indicates the need for a constant health monitoring in transit of cattle and adoption of measures for control and prevention of the disease from the complementary diagnostic methods recommendded by the Ministry of Agriculture, Livestock and Supply (simple test cervical and caudal fold), seeking ensure high sensitivity and specificity in identifing the causative agent of bovine tuberculosis. Also, it was concluded that the comparative cervical test when confronted with ELISA, has a low sensitivity, not being able to identify all positive animals from the herd. This fact is severe, since positive animals diagnosed as false negatives are permanent soureces of infection and spread of this disease in the herd.