Resposta à tuberculinização em bovinos sensibilizados com inóculos inativados de Mycobacterium avium e de Mycobacterium bovis
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Data
2016-07-01
Autores
Blankenheim, Thalita Masoti [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A tuberculose causada pelo Mycobacterium bovis é uma importante doença dos bovinos e constitui um grande problema de saúde animal, podendo também atingir humanos. Para o diagnóstico da infecção, e para desencadear as medidas sanitárias decorrentes desse diagnóstico, o Programa Nacional de Controle e Erradicação de Brucelose e Tuberculose (PNCEBT) estabelece a utilização de testes intradérmicos de tuberculinização. O objetivo deste estudo foi avaliar as respostas à tuberculina (PPD) aviária e à tuberculina bovina apresentadas por animais sensibilizados com inóculos inativados de M. bovis e de M. avium, e comparar os resultados do teste da prega caudal (TPC), do teste cervical simples (TCS) e do teste cervical comparativo (TCC) para diagnóstico da tuberculose bovina nos animais sensibilizados e em animais não sensibilizados. Os resultados mostraram que: a repetição dos testes não influiu na proporção de resultados positivos; houve animais sensibilizados com M. bovis que apresentaram reação até 500 dias após a sensibilização; em animais sensibilizados com M. avium, a especificidade do TCC foi superior à do TCS e à do TPC, e o TCC mostrou-se efetivo para discriminar reações induzidas pelo inóculo desse microrganismo; em animais sensibilizados com M. bovis, o TCC apresentou menor sensibilidade do que os outros dois testes; o ponto de corte do TCS e do TCC com melhor combinação de sensibilidade e especificidade foi inferior ao ponto adotado pelo PNCEBT para diagnóstico em animais naturalmente infectados; o TCS apresentou boa concordância com os outros dois testes, mas a concordância entre o TCC e o TPC foi apenas regular; as frequências das repostas às tuberculinas não apresentaram distribuição gaussiana, a não ser em alguns períodos pós-sensibilização ou então após transformação radicial ou logarítmica dos dados.
Tuberculosis caused by Mycobacterium bovis is an important disease in cattle e a great problem for animal health that can reach humans. For the diagnosis of the infection and the consequent sanitary measures, the National Program for Control and Eradication of Brucellosis and Tuberculosis (PNCEBT) establish the use of intradermal tuberculin tests. The aim of this study was to analyze the response to the avian and bovine tuberculin (PPD) developed by cattle sensitized with inactivated inoculum of M. avium and M. bovis. Another aim was to compare the results of the caudal fold test (CFT), the comparative cervical test (CCT), and the simple cervical test (SCT) for tuberculosis diagnosis in the sensitize animals and in animals that have not been sensitized. Repetition of the tests did not influence the proportion of positive results. There were animals sensitized with M. bovis showing reaction up to more than 500 days post sensitization. In animals sensitized with M. avium, the specificity of the CCT was higher than that of CFT and SCT, and CCT was able to discriminate the unspecific reaction induced by M. avium inoculum. In animals sensitized with M. bovis, CCT had lower sensitivity than the other two tests. The SCT and CCT cut-off with the best combination of sensitivity and specificity was lower than that adopted by the PNCEBT for the tuberculosis diagnosis in naturally infected animals. SCT hat good agreement with the other two tests, but the agreement between CFT and CCT was only moderate. The frequency of the responses to tuberculin did not show Gaussian distribution, but in some post sensitization periods or after square root or logarithmic transformation of the data.
Tuberculosis caused by Mycobacterium bovis is an important disease in cattle e a great problem for animal health that can reach humans. For the diagnosis of the infection and the consequent sanitary measures, the National Program for Control and Eradication of Brucellosis and Tuberculosis (PNCEBT) establish the use of intradermal tuberculin tests. The aim of this study was to analyze the response to the avian and bovine tuberculin (PPD) developed by cattle sensitized with inactivated inoculum of M. avium and M. bovis. Another aim was to compare the results of the caudal fold test (CFT), the comparative cervical test (CCT), and the simple cervical test (SCT) for tuberculosis diagnosis in the sensitize animals and in animals that have not been sensitized. Repetition of the tests did not influence the proportion of positive results. There were animals sensitized with M. bovis showing reaction up to more than 500 days post sensitization. In animals sensitized with M. avium, the specificity of the CCT was higher than that of CFT and SCT, and CCT was able to discriminate the unspecific reaction induced by M. avium inoculum. In animals sensitized with M. bovis, CCT had lower sensitivity than the other two tests. The SCT and CCT cut-off with the best combination of sensitivity and specificity was lower than that adopted by the PNCEBT for the tuberculosis diagnosis in naturally infected animals. SCT hat good agreement with the other two tests, but the agreement between CFT and CCT was only moderate. The frequency of the responses to tuberculin did not show Gaussian distribution, but in some post sensitization periods or after square root or logarithmic transformation of the data.
Descrição
Palavras-chave
Tuberculose, Diagnóstico, PPD, Comparação de testes, Tuberculosis, Diagnosis, Test comparison