Presence Of Mycobacterium Bovis Research Articles

Risk factors associated with the presence of Mycobacterium bovis in macroscopic lesions suspected as being caused by bovine tuberculosis detected in slaughterhouses

Mycobacterium bovis is a bacterium belonging to the Mycobacterium tuberculosis complex that causes tuberculosis in cattle and in other domestic and wild animals, as well as in humans. Disease control measures are carried out by slaughtering animals tested positive in the intradermal tuberculinization test and sanitation of their original living spaces, in addition to epidemiological surveillance carried out through the sanitary inspection of bovine carcasses in slaughterhouses. In the latter, official inspection services collect samples from macroscopic lesions suspected of bovine tuberculosis, which are then sent for laboratory analysis. Knowledge concerning the variables associated with the occurrence of M. bovis can aid in decision-making regarding control and disease eradication efforts. In this context, the aim of this study was to identify the risk factors for a positive M. bovis diagnosis in suspected bovine tuberculosis lesions obtained during epidemiological surveillance activities in the state of Mato Grosso, Brazil. A total of 105 suspicious lesions were analyzed using the Nested Polymerase Chain Reaction (nested q-PCR) method, of which 14 (13.33%) tested positive for M. bovis. Univariate and bivariate statistical analyses indicated that the variable “animal slaughter” was the only risk factor presenting statistical significance associated with the diagnosis of M. bovis (p < 0.05), demonstrating that macroscopic lesions suspected as being caused by bovine tuberculosis from animals with an in vivo diagnosis were 2.82 - fold more likely to result in a positive M. bovis diagnosis by molecular tests.

Detection of Antibodies against Mycobacterium bovis in Oral Fluid from Eurasian Wild Boar.

The presence of Mycobacterium bovis and other members of the Mycobacterium tuberculosis complex (MTC) is a main concern in wildlife populations such as the Eurasian wild boar (Sus scrofa). Tests detecting antibodies against the MTC are valuable for tuberculosis (TB) monitoring and control and particularly useful in suids. The development of accurate, efficient, and non-invasive new tools to detect exposure to MTC would be highly beneficial for improving disease surveillance. This study aimed to determine if antibodies against MTC could be detected in oral fluid (OF) samples by a new ELISA test (IgG detection) from naturally TB-infected wild boar. For this, individual, paired serum and OF samples were collected from 148 live wild boar in two TB-status areas from Spain and quantitatively used to validate the new ELISA test. Antibodies against MTC were widely detected in OF samples, for which a significant positive correlation (r = 0.83) was found with the validated serology test. OF ELISA sensitivity and specificity were 67.3% and 100%, respectively. The results of this work suggest that OF samples have the potential to be used for MTC diagnosis as a further step in TB surveillance and control in suid populations. Based on our results, further research is warranted and could be performed using non-invasive new tools directly in field conditions to detect exposure to MTC.

Mycobacterium bovis in humans and M. tuberculosis in animals in Nigeria: an overview from 1975-2014.

Zoonotic transmission of mycobacteria between humans and other animal species is an important aspect of the epidemiology of tuberculosis (TB) in regions of the world where the burden of the disease in humans and other animals is high. This is particularly important in areas in which sociocultural factors increase the possibility for interspecies transmission of different mycobacteria. Carrying out a review of the published literature involving laboratory-confirmed TB cases (by culture) and/or biochemical and molecular identification, we described the presence of Mycobacterium bovis and M. tuberculosis infections in humans and animals from 1975 to 2014. Overall, 1693 isolates of M. tuberculosis complex and other mycobacteria were identified and reported, of which 1131 represented M. tuberculosis, 286 represented M. bovis, 71 represented M. africanum, and 205 represented other mycobacteria. Importantly, 1.3% (15/1131) of the M. tuberculosis isolates reported were identified in cattle, while 8.0% (23/286) of the M. bovis isolates reported were isolated from humans. We suggest that representative sampling of TB cases in both hosts, studied by molecular identification tools, will help significantly in deciphering ongoing transmission between animals and humans in both directions and will enhance TB control in Nigeria.

Detection of Mycobacterium bovis in whey, by multiplex polymerase chain reaction (PCR) and bacteriological culture

The objective of this study was to detect the presence of Mycobacterium bovis (M. bovis) in whey. A total of 233 cow milk samples were analyzed together with 26 tank milk samples that came from dairy herds of several states of the Mexican Republic (Queretaro, San Luis Potosi, Guanajuato, Hidalgo, Coahuila). DNA was obtained from whey and used for polymerase chain reaction-multiplex (PCR-M). Tuberculosis complex was first identified through the detection of gene RD1. Positive samples were subjected to a second PCR-M with the primers for gene RD9 to identify M. bovis. Samples were bacteriologically cultured using conventional techniques for the isolation of mycobacteria. Cohen’s Kappa test (k) and Pearson’s Chi2 were carried out for statistical analysis. A 150 bp amplification product of the RD1 region was obtained, which corresponds to the tuberculosis complex, in 34/233 (14.59%) of the individual milk samples and in 4/26 (15.38%) of the tank milk samples. PCR-M with primer RD9, of the 34 individual samples and the 4 tank milk samples, gave an amplification product of 200 pb, which is the expected product for M. bovis. By bacteriological culture, six isolates were obtained; four in individual whey samples and two from tank milk samples, which were then classified by biochemical tests as M. bovis. The concordance between RD1, RD9 PCR-M and bacteriological culture was low, but there was a significant difference between diagnostic techniques with a P = 0.000. The results showed the potential of the PCR-M as a confirmatory test for the diagnosis of tuberculosis in cattle, as well as the advantage of using whey samples, that may be a possible source of infection for the herd and/or humans. Key words: Bovine tuberculosis, whey, polymerase chain reaction-multiplex (PCR-M), RD1, RD9, milk, isolation.

Post-mortem examination and laboratory-based analysis for the diagnosis of bovine tuberculosis among dairy cattle in Ecuador

Veterinary inspection in slaughterhouses allows for the detection of macroscopic lesions reminiscent of bovine tuberculosis, but the presence of Mycobacterium bovis must be confirmed by laboratory methods. This study aimed at comparing the performances of the standard diagnostic tools used to identify M. bovis in tissue specimens sampled from suspicious animals. During a two years period, 1390 cattle were inspected at the Machachi abattoir in the Mejia canton – Ecuador. A total of 33 animals with granulomatous lesions were detected, representing 2.33% (16/687) and 2.42% (17/703) animals examined in 2007 and 2008, respectively. Ninety-four tissue specimens were sampled and screened for the presence of mycobacteria. Acid-fast bacilli were identified in one third of the suspicious cattle (11/33) and suggestive microscopic lesions in 27.3% (9/33) of the samples examined by direct microscopy and histopathology, respectively. Culturing on Stonebrink medium and 16S-rRNA-based polymerase chain reaction (PCR) yielded 36.4% (12/33) and 27.3% (9/33) of positives, respectively. Compared to culture, other diagnostic procedures displayed a lower sensitivity, with 56.5% for PCR, and 43.5% for direct microscopy and histopathology; however, the specificity was higher (94.4% for PCR and microscopy, and 97.2% for histopathology). We conclude that reliable post-mortem laboratory testing either requires the combination of a set of available diagnostic tools or necessitates the development of improved new-generation tools with better sensitivity and specificity characteristics.

Zoonotic tuberculosis and brucellosis in Africa: neglected zoonoses or minor public-health issues? The outcomes of a multi-disciplinary workshop

Late in 2007, veterinary, medical and anthropological professionals from Europe and Africa met in a 2-day workshop in Pretoria, South Africa, to evaluate the burden, surveillance and control of zoonotic tuberculosis and brucellosis in sub-Saharan Africa. Keynote presentations reviewed the burden of these diseases on human and livestock health, the existing diagnostic tools, and the available control methods. These presentations were followed by group discussions and the formulation of recommendations. The presence of Mycobacterium bovis and Brucella spp. in livestock was considered to be a serious threat to public health, since livestock and animal products are the only source of such infections in human beings. The impact of these pathogens on human health appears to be relatively marginal, however, when compared with Mycobacterium tuberculosis infections and drug resistance, HIV and malaria. Appropriate diagnostic tools are needed to improve the detection of M. bovis and Brucella spp. in humans. In livestock, the 'test-and-slaughter' approach and the pasteurization of milk, which have been used successfully in industrialized countries, might not be the optimal control tools in Africa. Control strategies should fit the needs and perceptions of local communities. Improved intersectoral and international collaboration in surveillance, diagnosis and control, and in the education of medical and veterinary personnel, are advocated.

The experience of new European Union Member States concerning the control of bovine tuberculosis

On 1 May 2004, 10 new States joined the European Union, including Cyprus (CY), the Czech Republic (CR), Estonia (ES), Hungary (HU), Latvia (LA), Lithuania (LI), Malta (MA), Poland (PO), Slovakia (SK), and Slovenia (SN). Using OIE and published data, this paper summarises the status of bovine and human tuberculosis in animals in these countries between 1996 and 2003. National control programmes against bovine tuberculosis in cattle have been successful: the current herd incidence of this disease in cattle is currently lower than 0.2%, so all countries meet the OIE requirements for freedom from the disease. Furthermore, two countries have already been officially declared bovine tuberculosis-free EU States: the CR on 31 March 2004 (European Commission Decision No. 2004/320/EC) and SK on 4 March 2005 (Commission Decision No. 2005/179/EC). The last outbreak of bovine tuberculosis was diagnosed in cattle in CY (1928), ES (1986), LA (1989), SK (1993), CR (1995), and MA (2001). However, several issues of concern remain including the potential existence of a wildlife reservoir, the presence of Mycobacterium bovis, M. caprae, and other members of the M. tuberculosis complex (particularly M. tuberculosis or M. microti) in imported domestic or wild animals, and the potential for delayed detection of bovine tuberculosis in those States where annual tuberculin testing is no longer performed on cattle older than 24 months.

Mycobacterium bovis identification by a molecular method from post-mortem inspected cattle obtained in abattoirs of Mato Grosso do Sul, Brazil

The presence of Mycobacterium bovis in bovine carcasses with lesions suggestive of tuberculosis was evaluated. Seventy-two carcass samples were selected during slaughter inspection procedures in abattoirs in the state of Mato Grosso do Sul, Brazil. Seventeen (23.6%) of samples showed colonies suggestive of mycobacteria that were confirmed to be acid-fast bacilli by Ziehl-Neelsen staining. Polymerase chain reaction (PCR) using primers specific for M. bovis identified M. bovis in 13 (76.5%) isolates. The PCR-restriction enzyme pattern analysis using gene encoding for the 65-kDa protein and two restriction enzymes identified the remaining four isolates that were represented by two M. tuberculosis complex and two nontuberculous mycobacteria. The results are indicative of infection of slaughter cattle by M. bovis and other mycobacteria in the state of Mato Grosso do Sul.

Surveillance of wildlife for Mycobacterium bovis infection using culture of pooled tissue samples from ferrets (Mustela furo)

AIM: To compare culture results of homogenates of pooled lymph nodes from individual ferrets with and without macroscopic lesions of bovine tuberculosis for the presence of Mycobacterium bovis, and to determine whether homogenates from 10–30 ferrets could be combined and cultured without loss of sensitivity as a possible method for improving cost-effectiveness of surveillance for M. bovis infection in wildlife populations. METHODS: Numbers of colony forming units (cfu) of M. bovis present in cultures of homogenates of pooled lymph nodes from individual ferrets known to be infected and having no visible lesions (NVL) or macroscopic lesions consistent with bovine tuberculosis were determined. Prevalences of M. bovis infection in populations of ferrets in the Marlborough region of the South Island of New Zealand were determined by culturing homogenates of pooled lymph nodes from individual animals. Samples from homogenates from North Canterbury were combined to form pools representing 10, 20 and 30 animals and also cultured for M. bovis. RESULTS: Fewer M. bovis cfu were isolated from ferrets with NVL (mean=0.77 log10) compared with ferrets with macroscopic lesions (mean=3.22 log10; p<0.05). The mean prevalence of infection in eight different surveys involving 427 ferrets from the Marlborough region was 18% (range 8–44%), which included a small number of animals with macroscopic lesions of tuberculosis. Pooling of samples from up to 30 different ferrets with NVL did not reduce the sensitivity of detecting M. bovis-infected populations. CONCLUSION: Culturing of pools of lymph node samples detected a significant proportion of M. bovis-infected ferrets that would otherwise have gone unnoticed based on samples that had only macroscopic lesions. Culturing of samples pooled from up to 30 different ferrets could provide significant cost savings in surveys of wildlife for the presence of M. bovis infection without any apparent loss of sensitivity.