Comparison of the tuberculin test, histopathological examination, and bacterial culture for the diagnosis of tuberculosis (Mycobacterium bovis) in buffaloes (Bubalus bubalis) in Brazil

Abstract

Tuberculosis is a disease with a great zoonotic potential. It is considered a major obstacle to cattle production and is responsible for severe losses in several production systems. A comparative cervical test (CCT) was performed in 1140 buffaloes from different mesoregions of the state of Pará, Brazil, with the aim of comparing the sensitivity and specificity of CCT with histopathological examination and bacterial culture. Of the animals tested using CCT, 4.65% (53/1140) were positive, 2.98% (34/1140) were inconclusive, and 92.36% (1053/1140) were negative. Among the 168 sacrificed animals, 33 were positive, 18 were inconclusive, and 117 were negative by CCT, and samples from the sacrificed animals were collected for histopathological examination and bacterial culture. A qualitative evaluation of the tuberculin test was performed by comparing the test results with the histopathological and bacteriological results. The latter two tests yielded a prevalence of 4.16%, a sensitivity of 71.43%, and a specificity of 82.61%. Based on these results, we concluded that CCT yielded satisfactory results and can be applied in diagnostic studies in buffaloes. The prevalence rate obtained using three distinct diagnostic methods suggests that Mycobacterium bovis was present in a few animals in the population evaluated.

Diagnóstico histopatológico e molecular de lesões sugestivas de tuberculose em búfalos abatidos nos municípios de Macapá e Santana, estado do Amapá

“…A tuberculose pulmonar observada na maioria dos bubalinos do presente estudo é relatada como a forma mais comum da doença em búfalos (Freitas et al 2001, Laisse et al 2011. De forma semelhante, Albernaz et al (2015) observaram lesões sugestivas de tuberculose em linfonodos mediastínicos, além de achados macroscópicos em linfonodos mesentéricos de bubalinos. Em bovinos, a maioria dos achados macroscópicos localizam-se nos linfonodos respiratórios, parênquima pulmonar, linfonodos da cabeça e mediastínicos (Corner 1994, Whipple et al 1996, Proaño--Pérez et al 2011, Alzamora Filho et al 2014a, Alzamora Filho et al 2014b.…”

“…As lesões histológicas foram semelhantes às observadas por Kanameda & Ekgatat (1995), Laisse et al (2011), Albernaz et al (2015) na tuberculose bubalina, mantendo grande similaridade aos granulomas tuberculosos descritos na espécie bovina (Cancela & Marín 1993, Cassidy et al 1999, Wangoo et al 2005, Watrelot-Virieux et al 2006, Varello et al 2008. A detecção de bacilos álcool-ácido resistentes (BAAR) em somente três búfalos demonstra a baixa sensibilidade da técnica, uma vez que 13 animais apresentaram resultados positivos nas técnicas de Nested-PCR.…”

Comparison of the cutaneous response of the comparative cervical tuberculin (CCT) test with different reading times in buffaloes

“…It presents a chronic character and is characterized by the development of specific granulomas, called tubers (OLIVEIRA et al, 2007). Tuberculosis affects buffaloes as much as cattle, as far as the etiological agent, pathogenicity, clinical signs, pathological, epidemiological and zoonotic aspects are concerned (ALBERNAZ et al, 2015;MANSOUR, 1994). Roxo et al (1998) conducted studies evaluating the tuberculin test response in buffaloes and cattle, and observed that at 72 hours buffalo reactions were higher than in cattle.…”

Field Evaluation of the Interferon Gamma Assay for Diagnosis of Tuberculosis in Water Buffalo (Bubalus bubalis) Comparing Four Interpretative Criteria

“…The oldest test for the ante mortem diagnosis of TB is the single intradermal tuberculin test (SITT), recognized by the World Organization of Animal Health and the European Commission as the screening test, used in swamp buffalo (8,9) and in water buffalo (6). However, in buffalo species, SITT has been reported with low sensitivity (Se) and specificity (Sp) either in Syncerus caffer or in B. bubalis (9,10).…”

“…SICTT provides a better discrimination between animals infected with M. bovis and those infected with M. avium complex or environmental mycobacteria (15)(16)(17), increasing the Sp but with a still low Se (15,18,19). In Brazil, it has been reported that SICTT has 71.43% Se and 82.61% Sp in water buffalo (10).…”