The aim of the current study was to verify if cattle vaccinated against leptospirosis may react in diagnostic tests for brucellosis. Sixty cows were divided into 5 groups, each comprising 12 animals. Four groups were given different vaccines against leptospirosis, while the control group received only saline. Two doses of vaccine were given, as recommended by the manufacturers. Serum samples were collected on the first day of immunization (day 0) and on postvaccination days 7, 14, 21, 28, 35, 42, 49, 56, 96, and 126. All the serum samples were tested for brucellosis and leptospirosis. Twenty animals were reactive at least once to the Rose Bengal test, but by day 96, no further reactions were elicited by this test. Twenty-six samples were reactive to the Rose Bengal test, but only 7 remained positive in confirmatory tests: 1 to the 2-mercaptoethanol test, 2 to the fluorescence polarization assay, and 6 to indirect enzyme-linked immunosorbent assays. None of the samples was reactive in the complement fixation test. None of the animals in the control group was reactive. A significant difference was found between the control group and the groups vaccinated against leptospirosis, according to Fisher exact test. However, the groups were found to respond independently of the vaccine brand. The results indicate that cattle vaccinated against leptospirosis may show reactivity on screening tests for brucellosis.
ABSTRACT:Leptospirosis is a zoonotic disease that occurs worldwide, affecting pets and livestock that can be a source of infection for humans, considered therefore an important disease in public health. Thus, an investigation was made into the occurrence of anti-Leptospira agglutinins in several animal species on a farm located in the municipality of Uberlândia, state of Minas Gerais, Brazil. A total of 172 blood serum samples were collected from five species: cattle, dogs, goats, horses and sheep. The diagnosis was performed by means of the microscopic agglutination test (MAT), using a collection of 12 live antigens. Of the 172 animals evaluated, 62 (36%) were seroreactive, and the most frequent serovars in each species were: Hardjo (54.54%), Icterohaemorrhagiae (27.27%), and Autumnalis (18.18%) in cattle; Icterohaemorrhagiae (37.5%), Autumnalis (31%), Canicola (18.7%) and Hardjo (12.5%) in dogs; Grippotyphosa (75%) and Hardjo (25%) in goats; Icterohaemorrhagiae (50%), Grippotyphosa (37.5%) and Hardjo (12.5%) in horses, and Hardjo (34.78%); Grippotyphosa (26.08%); Bratislava (17.39%), Autumnalis (17.39%) and Icterohaemorrhagiae (4.4%) in sheep. It is believed that the occurrence of anti-Leptospira agglutinins can be traced back to a source of infection that is common to these species, or that the agent was probably transmitted between them because they live in close proximity to each other.
RESUMO: Objetivou-se com este estudo comparar diferentes métodos complementares de diagnóstico (macroscópico, histopatológico, sorológico e molecular) da tuberculose, em bovinos naturalmente infectados. O trabalho deu-se por meio de amostras colhidas em abate sanitário de 40 bovinos reagentes no teste cervical comparativo (TCC) para tuberculose. A inspeção macroscópica post mortem das carcaças foi acompanhada de colheita de amostras de muco nasal, sangue e tecido (fígado, pulmão e linfonodo mediastínico) para realização do exame de reação em cadeia pela polimerase (PCR), de Enzyme-Linked Immunosorbent Assay (ELISA) e histopatológico com colorações de hematoxilina-eosina (HE) e Ziehl-Neelsen (ZN), respectivamente. Dos 40 bovinos inspecionados no abate, 22 (55%) animais apresentaram algum tipo de lesão macroscópica sugestiva de tuberculose. Nos achados histopatológicos visualizados em HE, 13 (32,5%) carcaças apontaram alterações histológicas, sendo 6 (15%) nos linfonodos mediastínicos, 5 (12,5%) no fígado e 3 (7,5%) no pulmão. Não foi observada a presença de bacilos álcool-ácido resistentes em nenhuma das amostras avaliadas. O ensaio sorológico de ELISA/IDEXX(r) identificou um (2,5%) animal reagente, e o teste de PCR detectou DNA de Mycobacterium bovis em uma (2,5%) amostra. Concluiu-se que entre os exames complementares de diagnóstico avaliados nenhum foi capaz de detectar todos os animais que estavam positivos na tuberculinização, porém a associação de diferentes métodos pode garantir a confiabilidade do diagnóstico.
RESUMO:O objetivo deste trabalho foi analisar a frequência de lesões macroscópicas sugestivas de tuberculose em carcaças de bovinos reagentes ao teste intradérmico de tuberculose. Os animais do estudo foram provenientes de rebanhos de exploração leiteira, localizados nos municípios de Perdizes, Patos de Minas, Lagoa Formosa e Uberlândia, Minas Gerais. Foram avaliadas 140 carcaças de bovinos positivos no teste cervical comparativo. Durante o abate sanitário foi realizada inspeção post mortem das carcaças, e as lesões macroscópicas sugestivas de tuberculose foram registradas. Foram avaliados os linfonodos mediastínicos, fígado, pulmão e carcaça. Dos 140 bovinos examinados, 78 (55%) apresentaram algum tipo de lesão macroscópica sugestiva de tuberculose, 38 (49%) ocorreram exclusivamente nos linfonodos mediastínicos, 22 (28%) no fígado e 11 (14%) no pulmão; 5 (6%) carcaças apresentaram lesões no fígado, pulmão e linfonodo mediastínico, e 2 (4%) tiveram lesões no pulmão e linfonodo. Concluem-se que as lesões não visualizadas em bovinos reagentes ao teste tuberculínico podem ocorrer e estariam relacionadas principalmente ao estágio de evolução da doença, tempo insuficiente na inspeção post mortem para detecção, bem como reações inespecíficas para outras micobactérias. PALAVRAS-CHAVE: ABSTRACT:The aim of this study was to analyze the frequency of macroscopic lesions suggestive of tuberculosis in cattle reacting to the tuberculin test. Cattle of this study were from dairy herds located in the cities of Perdizes, Patos de Minas, Lagoa Formosa and Uberlândia, Minas Gerais, Brazil. We evaluated 140 cattle carcasses positive to the cervical comparative intradermal tuberculin test. During the slaughter a post-mortem inspection of carcasses was done, and the lesions suggestive of tuberculosis were recorded. We evaluated the mediastinal lymph nodes, liver, lung and carcass. Of the 140 cattle examined, 78 (55%) carcasses had some kind of macroscopic lesions suggestive of tuberculosis, 38 (49%) occurred only in the mediastinal lymph nodes, 22 (28%) in the liver and 11 (14%) in the lungs; 5 (6%) carcasses showed lesions in liver, lungs and lymph node, and 2 (4%) showed lesions in lung and lymph nodes. We concluded that lesions that were not visualized in bovine tuberculin skin test reagents may occur and are related mainly to the stage of the disease, insufficient time to detect the lesions, and nonspecific reactions to other mycobacteria.
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