Bovine Tuberculosis Lesions Research Articles

Bacilloscopy, Bacterial culture, and Spoligotyping of Mycobacterium bovis strains isolated from cattle in North Central Algeria

This study aimed to assess bovine tuberculosis-like cases in three slaughterhouses in North Central Algeria and to confirm these suspected cases using microscopic, bacteriological examination, and molecular biology technique. We highlighted the factors influencing the prevalence of the disease. Also, the genomic profiles of Mycobacterium tuberculosis complex (MTBC) strains isolated by Oligonucleotide typing technique (Spoligotyping) were determined. At the abattoir level, bovine carcasses were routinely inspected to detect visible abnormalities including suspicious lesions of bovine tuberculosis (BTB). At the laboratory level (Pasteur Institute, Algiers), Ziehl-Neelsen staining, bacterial culture, biochemical study (nitrate reduction test), and spoligotyping were performed to confirm suspected cases. On a total of 1300 bovine carcasses, 100 presented BTB-like cases (7.69%). Animals over 5 years of age were more affected compared to other age groups. Lesions were observed more often in females than in males and cattle of local breed were the most exposed to BTB-like cases (P<0.05). Bacilloscopy data were positive for 44 of the 100 suspected samples (44%) while bacteriology showed that 56 cultures were positive, while 35 were negative and 9 were contaminated. Molecular spoligotyping of 40 Mycobacterium strains samples showed 19 spoligotype profiles of M. bovis, of which 50% of profiles have been previously detected in the Mediterranean area and the three spoligotype patterns not previously reported were named SB2651, SB2652, SB2653 (by http:// www.Mbovis.org). Measures and means to prevent TB transmission among animals and to humans should be recommended, and more intensive investigations are required using both routine and molecular diagnostic techniques to understand and further explore MTBC.

Mycobacterium bovis naturally infected calves present a higher bacterial load and proinflammatory response than adult cattle.

Granulomas are characteristic bovine tuberculosis lesions; studying this structure has improved our understanding of tuberculosis pathogenesis. However, the immune response that develops in granulomas of young cattle naturally infected with Mycobacterium bovis (M. bovis) has not been fully studied. Our previous work described an atypical pattern in granulomatous lesions of cattle younger than 4 months (calves) naturally infected previously M. bovis that did not correspond to the histological classification previously proposed. Histologically, granulomas from calves lack a connective tissue capsule and have fewer multinucleated giant cells (MGCs) and more acid-fast bacilli (AFB) than the classic tuberculosis lesions found in cattle older than 1 year (adults); this suggests a deficient immune response against M. bovis infection in young animals. Therefore, we used IHC and digital pathology analysis to characterize the in situ immune response of granulomas from young and adult cattle. The immunolabeling quantification showed that granulomas from calves had more mycobacteria, CD3+ cells, IFN-γ, TNF-α, and inducible nitric oxide synthase (iNOS) than those of adult cattle. Furthermore, calf granulomas showed lower immunolabeling of MAC387+, CD79+, and WC1+ cells without connective tissue surrounding the lesion and were associated with less vimentin, Alpha Smooth Muscle Actin (α-SMA), and TGF-β compared with granulomas from adult cattle. Our results suggest that the immune responses in granulomas of cattle naturally infected with M. bovis may be age dependent. This implies that an exacerbated proinflammatory response may be associated with active tuberculosis, producing more necrosis and a lower microbicidal capacity in the granulomas of calves naturally infected with M. bovis.

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.

Evaluation of Postmortem Inspection Procedures to Diagnose Bovine Tuberculosis at Debre Birhan Municipal Abattoir.

Simple SummaryTuberculosis is transmitted from animal to human by consuming raw or under cooked meat and milk from infected animals. Careful meat inspection considering all parts of the carcass is very important. However, most abattoirs in Ethiopia are performing only routine meat inspection which does not examine the organs in detail. Failure to do so might result in undetected lesions. In this study, two methods (routine and detailed meat inspections) were compared to inspect carcasses at abattoir level. Our study clearly shows that the routine meat inspection method misses about 89% of the tuberculosis lesions identified by detailed meat inspection. Based on detailed meat inspection, overall 4.7% of lesions suggestive of bovine tuberculosis (bTB) were found in the carcass of cattle slaughtered at Debre Birhan municipality abattoir during the study period. However, the routine meat inspection only detected 0.5% of the carcasses examined as having Tuberclosis (TB) lesions. Anatomically, 66% of the lesions were found in the lungs and associated lymph nodes, 21% in lymph nodes of the head, and 13% in the lymph nodes of the gastrointestinal tract. Therefore, lesion distribution routine and detailed meat inspection and their sensitivity with respect to lesion detection was identified.Routine meat inspection in the abattoir was used to examine carcass for subsequent approval for consumption. However, the chance of missing lesions results in approval of carcass and/or the offal with lesions of tuberculosis. A cross-sectional study was conducted at Debre Birhan Municipal abattoir from October 2016 to May 2017. Lesion prevalence estimation and two meat inspection procedures’ efficacy evaluation was attempted. The breeds of the animals inspected were zebu breeds. Routine abattoir meat inspection involves visual inspection, palpation and incision of intact organs such as the liver and kidneys, as well as inspection, palpation and incision of tracheobronchial, mediastinal and prescapular lymph nodes. The detailed meat inspection involves inspection of each of the carcass. In this case, the seven lobes of the two lungs, lymph nodes and organs were also thoroughly examined. The cut surfaces were examined under bright light sources for the presence of an abscess, cheesy mass, and tubercles in detail. The study involved and compared both routine and detailed meat inspections at the abattoir. Chi-square test of independence and odds ratio were used to see the association of lesion and different risk factors. Based on detailed meat inspection, the overall lesion prevalence of bovine tuberculosis in the carcass of cattle slaughtered at Debre Birhan municipality abattoir was found to be 4.7% but only 0.5% of the carcass examined had detectable bovine tuberculosis lesions when routine abattoir meat inspection alone was used. The majority of the lesions were distributed to the lungs and associated lymph nodes. There was a significant association (p < 0.05) in TB infection rate and body condition score. In conclusion, this study has clearly indicated the prevalence of bovine tuberculosis lesions in the abattoir that are missed by routine abattoir meat inspection. In addition, it showed low sensitivity of the routine meat inspection procedure used. Hence, our study warrants immediate attention to strengthen the current meat inspection practices at Debre Birhan public abattoir.

Prevalence of bovine tuberculosis and distribution of tuberculous lesions in cattle slaughtered at Gondar, Northwest Ethiopia

ABSTRACT Background In Ethiopia, bovine tuberculosis (BTB) is a neglected disease that affects the economy and livelihoods of farmers. However, the available data is limited due to insufficient disease surveillance in the country. Therefore; this study aimed to assess the prevalence and distribution of lesions of BTB in cattle slaughtered at Gondar, Northwest Ethiopia. Methods Postmortem examinations were used to detect tuberculous lesions, while smear microscopy and histopathology were performed for the identification of acid-fast bacilli (AFB). Results Of 497 inspected slaughtered cattle, 45 (9.1%, 95%CI; 0.0668–0.1193) were diagnosed with BTB suggestive tuberculous lesions. A higher proportion of gross lesions was recorded in lymph nodes of lungs; at the mediastinal (14, 31.1%) and bronchial (10, 22.2%) lymph nodes, and followed by mesenteric lymph nodes (9, 20%). Of 45 tuberculous lesions; only 2 (4.4%) were identified as AFB positive by smear microscopy and histopathology. In the overall statistical analysis, body conditions of slaughtered cattle were found to be significantly associated with BTB tuberculous lesions (p < 0.05). Conclusion This finding provides the prevalence of BTB and distribution of tuberculous lesions in cattle slaughtered at the abattoir and highlights the need for a practicable control strategy of the disease in the region.

Immunohistochemical examination of osteopontin and sirtuin-1 expression in cattle tuberculosis

We evaluated osteopontin (OPN) and sirtuin-1 (SIRT-1) expression in bovine tuberculosis lesions. The organs of cattle with tuberculosis (TB) were examined for morphology, histopathology and immunohistochemistry of OPN and SIRT-1 expression. Macroscopic lesions commonly were localized in the lungs and mediastinal lymph nodes as well as in livers and hearts. Mycobacterial agents were detected in lesions using the Ziehl-Neelsen method. No OPN or SIRT-1 expression was detected by immunohistochemistry in normal tissues, whereas a marked increase in their expressions was observed in tuberculous lesions. The most intense immunopositive cells were Langerhans giant cells and inflammatory cells. Our findings indicate that OPN and SIRT-1 participate in the pathogenesis of bovine TB.

Vaccination of calves with Mycobacterium bovis Bacillus Calmette-Guerin reduces the frequency and severity of lesions of bovine tuberculosis under a natural transmission setting in Ethiopia.

SummaryBovine tuberculosis (bTB) is highly prevalent in intensive dairy farms of the urban “milk‐sheds” in Ethiopia, and vaccination could be a cost‐effective disease control strategy. In the present study, the efficacy of Bacillus Calmette–Guerin (BCG) to protect against bTB was assessed in Holstein–Friesian calves in a natural transmission setting. Twenty‐three 2‐week‐old calves were subcutaneously vaccinated with BCG Danish SSI strain 1331, and matched 26 calves were injected with placebo. Six weeks later, calves were introduced into a herd of M. bovis‐infected animals (reactors) and kept in contact with them for 1 year. In vitro and in vivo immunological tests were performed to assess immune responses post‐vaccination and during exposure. Successful vaccine uptake was confirmed by tuberculin skin test and IFN‐γ responses in vaccinated calves. The kinetics of IFN‐γ responses to early secretory antigen target 6 and culture filtrate protein 10 (ESAT6 and CFP10, respectively) and tuberculin skin test responses post‐exposure suggested that the animals were infected early after being placed in contact with the infected herd as immunological signs of infection were measurable between 2 and 4 months post‐initial exposure. Protection was determined by comparing gross and microscopic pathology and bacteriological burden between vaccinated and control calves. BCG vaccination reduced the proportions of tissues with visible pathology in vaccinates compared to control calves by 49% (p < .001) with 56%, 43%, 72%, and 38% reductions in the proportion of lesioned tisues in head, thoracic, abdominal lymph nodes, and lungs, respectively (p‐values .029–.0001). In addition, the lesions were less severe grossly and microscopically in vaccinated calves than in non‐vaccinated calves (p < .05). The reduction in the overall incidence rates of bTB was 23%, 28%, and 33% on the basis of the absence of gross pathology, M. bovis culture positivity, and histopathology, respectively, in vaccinated animals. In conclusion, BCG vaccination reduced the frequency and severity of the pathology of bTB significantly, which is likely to reduce onwards transmission of the disease.

Abattoir Based Prevalence, Economic Losses and Veterinarians High-Risk Practices Survey of Bovine Tuberculosis in Mid-Delta of Egypt

Bovine Tuberculosis (BTB) is a devastating zoonotic disease with extended influence on animals' productivity, economy and public health. Over three years, a total of 30,841 slaughtered animals (11,389 cows and 19,452 buffaloes) were surveyed for the presence of tuberculous lesions by post-mortem examination in El-Mahalla El-Kubra abattoir in Mid-Delta of Egypt. The overall prevalence of tuberculous lesions among all the slaughtered carcasses was 0.7% (219/30841). Lungs were the most common organ showed tuberculous lesions in cows with a prevalence of 0.24% (27/11389). However, tuberculous lesions were predominately detected in the intestine of buffalo carcasses with a prevalence of 0.45% (87/19452). There was no significant difference associated with either the annual pattern of BTB prevalence or seasonal variation for the two species over the 3 years of the study. Direct economic losses associated with the condemnation of 3105 Kg of meat and 162.5 Kg of liver due to tuberculous lesions was valued as 197,675 EGP (28544.3 USD). Majority of abattoir’s veterinarians injured accidentally during meat inspection at least once a week, yet they never use gloves for protection and some of them won’t cover their wound (42.9%) or even use antiseptics (57.1%). Reported carcasses with BTB lesions may pose a potential public health hazards either for abattoir’s workers or for public consumers when infected carcasses accidentally enter the food chain. Integrated disease surveillance, control of unauthorized slaughtering outside the abattoirs and educational training of veterinarians regarding occupational hazards and protective measures are urgently recommended in attempts to control such infections in the study region.

Assessment of the degree of concordance between the results of histopathological examination and bacterial culture in the diagnosis of bovine tuberculosis in Mexico

Bovine tuberculosis is a complex disease that is difficult to diagnose, control and eradicate and negatively impacts many farms. The objective of this study was to assess the degree of concordance between the results of histopathological examination and bacterial culture in the diagnosis of bovine tuberculosis lesions obtained in the laboratories certified by the Secretaría de Agricultura, Ganadería, Desarrollo Rural, Pesca y Alimentación (Ministry of Agriculture, Animal Production, Rural Development, Fisheries and Feeding) at the national level between January 2009 and December 2012 in Mexico. Tissue samples (10,818) from regular slaughter cattle that did not have tuberculin tests but had lesions suspected of having been caused by tuberculosis were sent to 10 authorized laboratories. Using Cohen’s kappa to measure the reliability of the diagnosis, a general concordance was obtained between the histopathological examination and bacterial culture results with a kappa of 0.634 and a 95% (0.618 – 0.650) confidence interval (CI), which shows good concordance between the two techniques at the national level. The laboratory in Chihuahua had the highest kappa [k=0.784, 95% CI (0.754–0.814)] and the laboratory of the La Laguna Region in the state of Coahuila had a low value of global concordance [k= 0.334, 95% CI (0.257–0.412)]. The number of positive samples in bacterial culture was low in Tamaulipas (21 samples), Sonora (41 samples), and Yucatán (45 samples) because tuberculosis prevalence in those states is ≤ 0.04%. The number of positive samples in bacterial culture was low in Tamaulipas (21 samples), Sonora (41 samples), and Yucatán (45 samples) because tuberculosis prevalence in those states is ≤ 0.04%. The reason for the disagreement between the two tests among some laboratories includes factors such as a lack of economic resources, infrastructure or personnel training. Correct sampling procedures, storage facilities, and shipping and sample processes are important in optimizing the bacteriological and histopathological results and obtaining correct diagnoses and differential diagnoses of bovine tuberculosis.

Assessment of the degree of concordance between the results of histopathological examination and bacterial culture in the diagnosis of bovine tuberculosis in Mexico

Bovine tuberculosis is a complex disease that is difficult to diagnose, control and eradicate and negatively impacts many farms. The objective of this study was to assess the degree of concordance between the results of histopathological examination and bacterial culture in the diagnosis of bovine tuberculosis lesions obtained in the laboratories certified by the Secretaria de Agricultura, Ganaderia, Desarrollo Rural, Pesca y Alimentacion (Ministry of Agriculture, Animal Production, Rural Development, Fisheries and Feeding) at the national level between January 2009 and December 2012 in Mexico. Tissue samples (10,818) from regular slaughter cattle that did not have tuberculin tests but had lesions suspected of having been caused by tuberculosis were sent to 10 authorized laboratories. Using Cohen’s kappa to measure the reliability of the diagnosis, a general concordance was obtained between the histopathological examination and bacterial culture results with a kappa of 0.634 and a 95% (0.618 – 0.650) confidence interval (CI), which shows good concordance between the two techniques at the national level. The laboratory in Chihuahua had the highest kappa [k=0.784, 95% CI (0.754–0.814)] and the laboratory of the La Laguna Region in the state of Coahuila had a low value of global concordance [k= 0.334, 95% CI (0.257–0.412)]. The number of positive samples in bacterial culture was low in Tamaulipas (21 samples), Sonora (41 samples), and Yucatan (45 samples) because tuberculosis prevalence in those states is ≤ 0.04%. The reason for the disagreement between the two tests among some laboratories includes factors such as a lack of economic resources, infrastructure or personnel training. Correct sampling procedures, storage facilities, and shipping and sample processes are important in optimizing the bacteriological and histopathological results and obtaining correct diagnoses and differential diagnoses of bovine tuberculosis.

Isolation and Phylogenetic Characterization of Streptococcus halichoeri from a European Badger (Meles meles) with Pyogranulomatous Pleuropneumonia

Clinical and pathological studies in European badgers (Meles meles) are limited. Badgers play a significant role in the epidemiology of bovine tuberculosis (TB) in some countries and an accurate diagnosis is needed for this infection. However, the lesions of bovine TB are similar to those associated with other pathogens, making pathological diagnosis difficult. In the present study, Streptococcus halichoeri was isolated from a European badger with pyogranulomatous pleuropneumonia and suspected of having tuberculosis. TB and other pathogens able to induce similar lesions were ruled out. Comparative 16S rRNA and rpoB gene sequencing studies showed an identity of 99.51% and 98.28%, respectively, with S. halichoeri. This report represents the third description of this bacterium and the first in an animal species other than the grey seal (Halichoerus grypus). It also shows that S. halichoeri can be associated with a pathological process characterized by granulomatous inflammation and resembling tuberculosis.

Population structure, genotypes and pathogenic phenotype of Mycobacterium bovis in Argentina (and Latin America)

Mycobacterium bovis (M. bovis) is the causative agent of bovine tuberculosis, a global disease that in Argentina affects approximately 5% of cattle, particularly dairy cattle. Several genotyping methods that distinguish between different isolates of M. bovis have been reported. Among them, the most convenient are spoligotyping (a reverse line probe assay) and genotyping by Variable Number of Tandem Repeat (VNTR). In Argentina, unlike what happens in other countries in the region, there is a highly predominant spoligotype (SB0140), but the reason for this dominance is still unknown. In five countries of Latin America, a total of 244 different spoligotypes were found: 8.4% of isolates had orphan spoligotypes, whereas 91.6% formed clusters. Only 1 spoligotype was common to Argentina Brazil and Chile. However, there were 10 spoligotypes shared between Argentina and Brazil; 2 between Argentina and Chile; and 1 between Chile and Brazil. In conclusion, despite the diversity of spoligotypes found in the five countries, there are major patterns predominating in Argentina, Brazil and Chile. These clusters may reflect a long-lasting active transmission of bovine tuberculosis.The other goal of this study was to investigate whether there are M. bovis genotypes with differential virulence properties. While this is a topic already elucidated for other pathogenic bacteria, the properties for M. bovis are still unknown. First, the virulence of M. bovis isolates were tested in a mice model of progressive disease. Balb/c mice infected with the M. bovis reference strain AN5 showed a 50% survival after four months of infection, with a moderate number of lung bacillary counts. Two weeks after inoculation, it induced a strong inflammatory response with numerous granulomas and progressive pneumonia. In turn, the strain M. bovis 04-303, isolated from a wild boar, was the most lethal, and its most striking feature was sudden pneumonia development with extensive necrosis. Strain 04-302 induced a similar pathology, although to a lesser extent. In contrast, strains 534, V2 (both from cattle) and 02-2B (from humans) were less virulent, permitting higher survival after four months of infection, Thus, as reported with Mycobacterium tuberculosis clinical isolates, M. bovis also showed virulence variability. This variability can be attributed to the induction of different immune response profiles. The virulence of the most virulent strain was also evaluated in guinea pigs and cattle showing the same results. On the other hand, the genome of this strain was sequenced showing that the genome encodes for 3988 protein and 49 RNA genes. Some particularities of the genome sequence and a deduced proteome will be shown.A methodology was designed to establish whether a relationship exists between the genotype of M. bovis and the degree of pathogenicity it causes in cattle. The essence of this methodology is to establish a correlation between the genotype of M. bovis, the degree of progression of tuberculosis and animal age. To this aim, three correlates were used: (1) The genotype was based on the spoligotype; (2) The degree of bovine tuberculosis lesions were quantified with a score based on clinical observations in slaughterhouses, such as the number and location of granulomas, and the histopathologic features; and (3) These data were stratified by the approximated age of the animal, determined by the category (calf, steer, heifer, etc). Thus, the virulence was studied in infected cattle, and not in laboratory animals, through a detailed analysis of the lesions found in the slaughterhouses. The lesions were processed for histopathology and culture. As a control for genetic uniformity, the alleles of BoLA DRB3 were sequenced. Lineages with the highest pathogenicity scores were of low abundance and were found in the south of Cordoba province.

Seasonal prevalence of Bovine Tuberculous lesions in cattle slaughtered in Yola abattoirs

Bovine tuberculosis is endemic in Nigeria. There is paucity of information on the prevalence of bovine tuberculous lesions in cattle slaughtered in Yola, Adamawa state. The annual prevalence and seasonal variation of bovine tuberculous lesions were assessed based on abattoir records of tuberculosis lesions from 2008 to 2012. The overall prevalence of bovine tuberculosis lesions from 2008 to 2012 ranges from 8.68% (6.03 – 11.33) in 2008 to 10.33% (8.63 – 12.03%) in 2012 with peak prevalence of 12.73% in 2011. Types of lesions were not recorded systematically, however, lesions that were observed ranges from TB granuloma, TB abscesses with yellowish pus, caseous necrotic tubercles, multiple necrosis to focal granulomas. Annual prevalence of bovine tuberculosis lesions recorded in Yola abattoirs differ significantly (p ? 0.05). Prevalence of tuberculous lesions in Yola abattoirs was significantly influenced by season (p &lt; 0.05). Tuberculosis is endemic in cattle slaughtered in abattoirs meant for human consumption in Yola, therefore humans are at risk of acquiring zoonotic tuberculosis through consumption of contaminated meat.DOI: http://dx.doi.org/10.3329/bjvm.v11i2.19125 Bangl. J. Vet. Med. (2013). 11 (2): 113-120

Prevalence of Bovine Tuberculosis in Abattoirs of the Littoral and Western Highland Regions of Cameroon: A Cause for Public Health Concern

Bovine tuberculosis (BTB) is widespread but poorly controlled in Africa and M. bovis is posing threats to human health. The risk of cattle handlers to M. bovis prevalence and public health significance of BTB in Cameroon were assessed. Slaughter inspection records from major cities revealed that BTB detection rates in cattle from 0.18% to 4.25% and BTB lesions were most common. Analyses of tissues and sera confirmed BTB in 31% (Ziehl-Neelsen), 51% (culture), and 60% (antibody detection) of test cattle. Among cattle handlers, 81.9% were aware of BTB, 67.9% knew that BTB is zoonotic, and 53.8% knew one mode of transmission but over 27% consumed raw meat and/or drank unpasteurized milk. Respondents who had encountered tuberculosis cases were more informed about zoonotic BTB (P < .05). Tuberculosis is prevalent in cattle destined for human consumption in Cameroon with serious public health implications. Targeted monitoring of infected animal populations and concerted veterinary/medical efforts are essential for control.

Isolation of Mycobacterium bovis from brushtail possums with non-visible lesions

AIM: To determine the prevalence of Mycobacterium bovis infection in brushtail possums (Trichosurus vulpecula) that did not have macroscopic lesions of bovine tuberculosis, and to evaluate culture of pooled tissues from multiple possums as a method for determining the M. bovis-infection status of wildlife populations in New Zealand. METHODS: Pools of selected tissues were collected from possums from four different populations known to be infected with M. bovis. Tissue pools from individual animals, and combined pools from multiple animals, were cultured for M. bovis. RESULTS: In the four populations investigated, the prevalence of possums with macroscopic lesions confirmed by culture to be infected with M. bovis ranged from 1 to 19 (mean 31/283; 10.9)%. The prevalence of possums with non-visible lesions that were culture positive for M. bovis in the same populations ranged from 4 to 10 (mean 24/283; 8.5)%. The mean of the log10 cfu of M. bovis of the macroscopic lesions and of the culture-positive samples that did not have visible lesions was 3.85 (SE 0.26) and 1.46 (SE 0.26) log10 cfu, respectively (p<0.01). Mycobacterium bovis was cultured from pools of 30–50 animals in the four populations studied. CONCLUSIONS: The finding of M. bovis infection in possums with non-visible lesions identified a potential deficiency of declaring possum populations free of M. bovis on the basis of absence of macroscopic lesions. The culturing of pools of selected tissues from multiple animals without visible lesions can be used to reduce laboratory costs of possum surveys without a major reduction in the ability to detect M. bovis infection.

Identification of Mycobacterium bovis Isolates by a multiplex PCR

Isolates from suggestive bovine tuberculosis lesions were tested by a multiplex polymerase chain reaction (m-PCR) targeting for RvD1Rv2031c and IS6110 sequences, specific for M. bovis and Mycobacterium tuberculosis complex respectively. The m-PCR successfully identified as M. bovis 88.24% of the isolates.

Patterns of lesions of bovine tuberculosis in wild red deer and wild boar

The data obtained from a survey of Mycobacterium bovis infection in wild red deer (Cervus elaphus) and wild boar (Sus scrofa) conducted in France in the 2005/06 hunting season were...

Prevalence of bovine tuberculosis at the SODEPA Douala abattoir, Cameroon (1995 – 2003)

This paper reviews tuberculosis and other pathological cases of slaughtered cattle recorded in “SODEPA” ( Societe de Developpement et d'Exploitations des Productions Animales ) Douala abattoir from April 1995 – May 2003 to determine the status of Bovine tuberculosis and other pathological conditions in Zebu cattle. Out of a total of 385,784 (3782.20 ± 425.02) zebu cattle slaughtered during this period, 3,893 (20.17 ± 25.35) pathological lesions were recorded with 81.53 % (3174; 32.72 ± 30.30) of them being due to tuberculosis. Prevalence rates of 1.01% for all the cases put together, 0.82% for tuberculosis alone and 0.19% for the non-tuberculosis cases were obtained for the 8-year study period. The other 18.47% (719; 7.90 ± 5.80) of non-tuberculosis cases were made up of liver (76.77%), non-tuberculosis lung (10.29%), cysticercosis (5.98%), enlarged kidney (2.50%), traumatic (2.22%) and pericardiac (2.22%) lesions. Bovine tuberculosis lesions were generally 3 – 5 times more prevalent (P Keywords : Zebu cattle, pathological lesions, tuberculosis, prevalence, abattoir, Douala- Cameroon Cameroon Journal of Experimental Biology Vol. 1(2) 2005: 116-120

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.

Breakdown severity during a bovine tuberculosis episode as a predictor of future herd breakdowns in Ireland

A retrospective cohort study of Irish cattle herds investigated whether the severity of a herd’s bovine tuberculosis (BTB) breakdown was a predictor of the hazard of a future BTB breakdown in that herd. Data on 10,926 herds not having had BTB in 1995 (the “non-exposed” group) were obtained using a 10% random sample from all herds without BTB in 1995. Data on 6757 herds that had a new BTB breakdown in 1995 (the “exposed” group) were obtained and categorized into five increasing exposure-severity classes based on the total number of standard reactors (to the single intra-dermal comparative cervical tuberculin test) detected during the breakdown. Exposed herds were deemed to be free of BTB after they passed a 6-month check test; non-exposed herds were deemed free as of the date of the first negative herd-test in 1995. In the 5 years after 1995, 18% of the non-exposed herds had a BTB breakdown, whereas 31% of the exposed herds had a subsequent breakdown. Relative to the hazard for non-exposed herds, the hazard for the first future singleton standard reactor breakdown, was 1.6-times higher for exposed herds with only 1 standard reactor in 1995, and 1.8-times higher for those exposed herds with 4–8 standard reactors during the 1995 episode. When the outcome for future breakdowns was 2 or more standard reactors, the hazard ratios ranged from 1.6 for exposed herds with only 1 standard reactor in 1995 up to 2.9 in exposed herds with 8 or more standard reactors during the 1995 episode. The latter hazard ratio varied over time, decreasing to 1.7 after 3 years of risk. The hazard of a future BTB breakdown increased directly with number of cattle in the herd, a positive history of previous BTB in the herd, and the local herd prevalence of BTB. The presence of confirmed BTB lesions in reactor cattle was not predictive of the future breakdown hazard when the effects of other factors were controlled.