Preliminary Investigation of Bovine Tuberculosis in Suspected Beef from a Metropolitan Abattoir in Ghana with Ziehl-Neelsen Microscopy

Abstract

Bovine tuberculosis is an important zoonotic disease transmissible through aerosols inhalation and the ingestion of contaminated milk and meat from cattle. Abattoirs in Ghana mainly depend on post-mortem examinations as means of diagnosing the presence of mycobacterium in meat (beef). A Ziehl-Neelsen microscopy was used to investigate the presence of Mycobacterium bovis as Acid-Fast Bacilli (AFBs) in beef samples from the Kumasi Metropolitan abattoir; thereby vetting post-mortem examinations at the abattoir. Lesioned lung tissues and calcified or puss-filled thoracic lymph nodes were collected at post-mortem as directed by an expert veterinarian. A total of 159 samples from 130 cattle (bulls and cows) were used in this study from April to July 2006. Ninety-five (i.e., 73.1%) of the 130 cattle sampled were positive for AFBs, whilst the remaining thirty-five (26.9%) were negative. Out of the total 159 individual samples specimen collected, 114 (71.7%) were found with AFBs. A total of 64 lung tissues and 95 lymph nodes were collected, respectively. Interestingly, 70.3% of the lung tissues were AFB-positive with 69 (72.6%) out of the 95 lymph nodes, also being positive. The ZN microscopy was effective in detecting the presence of mycobacteria, as 73.1% of the suspected samples were AFB-positive. It presupposes that, abattoir post-mortem examinations were also efficient however; the lapses of non-detection of asymptomatic carcasses could also pose a serious health risk to consumers. Also, lack of a functional on-site laboratory and a practical monitoring system was found to be unfavourable to the maintenance of meat quality. Detailed laboratory examinations (such as culture, PCR and other biochemical tests) to augment ZN microscopy is recommended for thorough detection of bovine tuberculosis.

Prevalence and Direct Economic Losses from Bovine Tuberculosis in Makurdi, Nigeria

“…Results from abattoir based investigation have provided useful information on bovine tuberculosis over the years in Africa [7, 25, 26]. However, not a novel finding per se, in developing countries where laboratories are ill equipped and with endemic bovine tuberculosis, postmortem diagnosis by detection of macroscopic lesions remains the best option [7, 26].…”

“…Localized tuberculosis organ/carcase is trimmed and then passed for human consumption, while massive or generalised tuberculosis organ/carcase is declared unfit for human consumption [25]. …”

Slaughter surveillance for tuberculosis among cattle in three metropolitan abattoirs in Ghana

“…In the past, a study to assess beef quality at necropsy using Ziehl-Neelsen (ZN) microscopy of suspicious beef samples obtained from the main abattoir in Kumasi, the second largest city in Ghana, indicated a significant level of contamination by acid-fast species. In that study, 73.1% of carcasses harbouring lesions suggestive of BTB were found to be acid-fast on pre-culture microscopic examination (Adu-Bobi et al, 2009). There is also a paucity of information regarding the prevalence of BTB amongst cattle herds in Ghana.…”

Differences in Primary Sites of Infection between Zoonotic and Human Tuberculosis: Results from a Worldwide Systematic Review

“…Whilst M. tuberculosis -related human TB ( Mt TB) is one of the most devastating infectious diseases worldwide, the public health relevance of zoonotic TB (zTB) appears to be minor in industrialized countries, where milk pasteurization is regularly performed [3]. However, in developing countries where control programmes for TB in livestock are absent and milk pasteurization is not done routinely, zTB may be of considerable importance [4]–[6]. A recent systematic literature review estimated incidence rates of zTB of approximately 7/100'000 human population/year in Africa [7].…”

“…This relatively low incidence rate notwithstanding, the study revealed that considerable rates of zTB exist in certain high-risk populations. Moreover, cases of zTB could be considerably under-diagnosed and consequently under-reported, particularly in developing countries [4]–[6].…”