Laboratory Diagnosis of Bovine Tuberculosis

Abstract

Lesions of suspected bovine tuberculosis were examined by culture, histopathology and auramine-O (AO) stained smears and the findings correlated with field aspects of the disease. Of 642 lesions considered to be tuberculous, 62.0% yielded M. bovis and 4.5% other mycobacteria (OM). M. bovis and OM were recovered also from 0.6% and 3.6% respectively of 165 cattle which gave tuberculin reactions but had no visible lesions at slaughter. Of 262 lesions in which a histopathological diagnosis other than tuberculosis was made, 1.5% and 3.0% yielded M. bovis and OM respectively. All OM isolates tested belonged to the Mycobacterium-avium-intracellulare-scrofulaceum (MAIS) complex with a predominance of serotype 2. A good relationship was found between the recovery of mycobacteria and histopathology but examination of smears revealed 22.0% apparent false negatives. Apparent false negative culture results were also reported for 35.8% of lesions positive on histopathology and smear examination. The majority of herds yielding M. bovis contained reactors to the tuberculin test and many of these had lesions of tuberculosis. In contrast, herds yielding OM seldom contained reactors to the tuberculin test and rarely reactors with tuberculous lesions. The thoracic cavity was the main site of lesions from infections by M. bovis and OM.

THE DISTRIBUTION OF MYCOBACTERIUM BOVIS IN QUEENSLAND CATTLE HERDS WITH OBSERVATIONS ON THE LABORATORY DIAGNOSIS OF TUBERCULOSIS

“…Detailed studies of the accuracy of various laboratory procedures in the diagnosis of tuberculosis a t post mortem have been published by Tammemagi et al(1973) and Claxton et al(1979). Further observations on the accuracy of cultural and histological procedures are contained in this report which also includes data on the distribution of Mycobacteriurn bovis infection and o n the mycobacterial flora of no visible lesion (NVL) reactor cattle.…”

Molecular Characterization of Mycobacterial Ribonucleotide Reductase (RNR) and its Implication as a Novel Drug Target

“…From this phylogenetic analysis we also found that the species of Mycobacterium were differentiated on the basis of their host dependency. The species like M. africanum, M. bovis, M. tuberculosis M. canettii and M. kansasii, causing human tuberculosis [37][38][39][40][41] were grouped in sub cluster A1. Likewise M. intracellulare causing pulmonary tuberculosis in humans [42], M. avium causing tuberculosis in poultry and captive birds [43] and also in immune compromise patients/HIV patients [44], M. avium paratuberculosis causing tuberculosis in cattle [45], and M. avium hominissuis causing pulmonary tuberculosis in pigs, humans and horses [46,47] were placed in sub-cluster A3.…”

A Comparison of Ziehl-Neelsen Staining and Fluorescent Microscopy for Diagnosis of Pulmonary Tuberculosis

“…Serological tests are currently not reliable enough for the diagnosis of tuberculosis [2]. Microscopic examination and culture are still essential elements of the bacteriological diagnosis of tuberculosis in microscopic examination; the diagnosis of tuberculosis is confirmed on the basis of demonstration of tubercle bacilli in the sputum or any other pathological material [1,2,4,6]. Smear examination is believed to be simple, cheap, quick and practicable and effective case finding method for developing countries.…”

“…In this a smear is made from the specimen and stained with fluorescent stain called auramine .The auramine stain enters the wall of Mycobacterium tuberculosis bacterial cell and makes them glow against dark background under UV light [4].Microscopic examination under low power objective will reveal mycobacteria as glowing yellow white, rice like bacteria in the smear,.…”