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1.
In this study we have characterized M. bovis isolates from a herd of cattle in Uvalde, Texas in which 52 of the 193 animals selected at random in 1994 from a herd of 331 were caudal fold skin-test positive. Thirty-two of 52 skin-test positive cattle had gross lesions at slaughter, and isolations of M. bovis were made from 29 animals. The herd was comprised of Red Devon cattle purchased between 1978 and 1980 (n = 26) and breeding bulls (n = 3) introduced at later times, and all were tuberculosis test negative at the time of purchase. Other animals were natural additions (offspring) of these cattle. One additional animal, a Holstein present on the ranch at the time of purchase in 1976, was retained to nurse orphaned and weak calves. Using several molecular fingerprinting techniques we have verified a clonal relationship among the M. bovis isolates consistent with infection originating with a single strain. The molecular fingerprint patterns demonstrate the stability of the profiles despite persistence and spread of the organism within the herd for two decades and confirms their use in epidemiological tracing.  相似文献   

2.

Cattle are the domestic animal reservoir for Mycobacterium bovis (M. bovis) which also affects other domestic animals, several wildlife species and humans leading to tuberculosis. The study area is in a resource-poor community that is surrounded by several game parks, where M. bovis infection has been previously diagnosed in wildlife. A cross-sectional study was carried out to determine the prevalence of M. bovis infection in 659 cattle from a total of 192 traditionally managed herds using the BOVIGAM® interferon gamma assay (IFN-γ). Infection was confirmed by post mortem examination and M. bovis isolation from three test-positive cattle. Genotyping of the M. bovis isolates was done using spoligotyping and VNTR (variable number of tandem repeats typing). The apparent M. bovis prevalence rate in cattle at animal level was 12% with a true population prevalence of 6% (95% Confidence interval (C.I) 3.8 to 8.1) and a herd prevalence of 28%. Spoligotyping analysis revealed that the M. bovis isolates belonged to spoligotype SB0130 and were shared with wildlife. Three VNTR profiles were identified among the SB0130 isolates from cattle, two of which had previously been detected in buffalo in a game reserve adjacent to the study area. The apparent widespread presence of M. bovis in the cattle population raises a serious public health concern and justifies further investigation into the risk factors for M. bovis transmission to cattle and humans. Moreover, there is an urgent need for effective bTB control measures to reduce infection in the communal cattle and prevent its spread to uninfected herds.

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3.
A study was conducted to determine the prevalence of Mycobacterium bovis-infection and atypical mycobacterioses in different cattle herd management systems in and around Morogoro, Tanzania. Between April and June 2005, a total of 728 bovines from 49 herds were tested for M. bovis-infection and atypical mycobacterioses. Milk samples were taken from tuberculin positive animals and analysed for the presence of mycobacteria. Total prevalences of 2.5% and 10.1% were found for M. bovis-infection and atypical mycobacterioses respectively, with more M. bovis-infection in cattle in the extensive management system and more atypical mycobacterioses in cattle in the intensive management system. From 8 out of 42 milk samples (19%) atypical mycobacteria were cultured. A higher prevalence of M. bovis-infection in the extensive sector could be due to several factors. In addition, such high prevalence puts herd owners and their families at risk for BTB. Therefore control of BTB, as well as education of cattle owners is important, especially in the extensive sector.  相似文献   

4.
Mycoplasma bovis is an important cause of calf pneumonia worldwide. In this study, we examined 140 cattle at slaughter comprising 70 veal calves and 70 beef cattle; 115 animals with pneumonic lesions and 25 without. Lung samples were submitted for bacteriological, histological, and M. bovis-immunohistochemical analyses. Serology for M. bovis was positive in 76% of beef cattle and 100% of veal calves. M. bovis was isolated only from veal calves in 16 out of 64 pneumonic cases. M. bovis was detected by immunohistochemistry in seven bacteriologically positive cases. M. bovis antigen was associated with bronchogenic necrosuppurative or fibrinonecrotizing lesions. Bacteriologically positive and immunohistochemical negative cases were associated with catarrhal bronchointerstitial pneumonia. Results suggest that M. bovis infection may develop into a severe necrosuppurative bronchopneumonia or fibrinonecrotizing pneumonia when associated with a high number of intralesional organisms or, conversely, into a mild catarrhal bronchointerstitial pneumonia when associated with a low number of organisms.  相似文献   

5.
We analysed the individual-animal data from six of the nine outbreaks of tuberculosis in Canadian cattle and cervids from 1985 to 1994. A “positive/reactor” animal was one which had either a positive culture or a positive or suspicious reaction on a mid-cervical, comparative cervical, or gross or histopathological test for tuberculosis. Individual-animal data were collected only for herds which had one or more positive/reactor animals. Data were collected from the outbreak records in the Regional or District offices of Agriculture and Agri-food Canada’s Animal and Plant Health Directorate. The within-herd spread of Mycobacterium bovis was studied by determining the most-likely date at which the herd was first exposed to M. bovis and the number of reactions which had developed by the time the herd was investigated. The animal-time units at risk in the herd were probably overestimated, resulting in conservative estimates of the within-herd incidence rates. Negative-binomial regression was used to investigate factors which might have influenced the within-herd spread of tuberculosis. Increasing age appeared to be a risk factor for being a positive/reactor animal. When compared to animals 0–12 months old, animals 13–24 months old had an incidence rate ratio (IRR) of 7.6, while animals >24 months old had an IRR of 10.4 (p=0.009). Actual and predicted incidence rates for tuberculosis in mature (>24 months old) animals were calculated. Actual and predicted incidence rates were similar for cervids, within an outbreak. There was more variability between actual and predicted rates in the dairy and beef animals. In the one outbreak (Ontario) where there were positive/reactor cervid, dairy and beef herds, the actual incidence rate for cervids (IR=9.3 cases per 100 animal-years) was almost twice that of dairy cattle (IR=5.0) and three times that of beef cattle (IR=3.1).  相似文献   

6.
Between December 1985 and March 1987 an enzyme-linked immunosorbent assay (ELISA) was used with 3774 sera to estimate the prevalence of antibodies to Mycoplasma bovis in sera from three age groups of cattle in four dairies in California and to test for possible associations between the presence of M. bovis antibodies and the age or breed of the cattle and the farm. Unadjusted and adjusted associations were evaluated using the -square test for associations and multiple logistic regression analysis, respectively.There was a tendency for the proportion of cattle seropositive for M. bovis to increase steadily and approximately linearly with age (p<0.05). There was also a statistically significant relationship bbetween a M. bovis seropositive test and being from Farm IV (p<0.05). Farm IV was the largest of the four dairies and this association may be due to the effect of herd size.These findings confirm the ubiquitous distribution of antibodies to M. bovis in dairy cattle in California and also support previous reports of herd size as an important factor in mycoplasmal mastitis.  相似文献   

7.
Three sampling procedures were compared to determine the optimal technique for isolating mycoplasmas in cattle with respiratory diseases. The prevalence of mycoplasmas isolated from these animals is also reported. In the first group, bronchoalveolar lavage (BAL) and nasal swab cultures were compared with the corresponding lung cultures from cattle necropsied for fatal respiratory diseases (n = 20). In a second group, nasal swabs were compared with corresponding BAL cultures in living animals with recurrent respiratory pathologies (n = 49). There was complete agreement between the paired BAL and lung cultures. In contrast, nasal cultures were not representative of the mycoplasmas present in the lower respiratory airways. The relative sensitivity and specificity of the nasal swab technique compared to BAL in living animals confirmed that the nasal swab cultures were not predictive of lower respiratory airway pathogens, such as Mycoplasma bovis. BAL is considered to be the best method for isolating M. bovis in cattle with respiratory diseases as it combines reliability and feasibility under field sampling conditions. In the present study, Mycoplasma dispar (43%) and M. bovis (29%) were mainly isolated in mixed infections. This confirms the need to search for mycoplasmas in routine examinations and to take them into account in therapeutic strategies for respiratory diseases in cattle.  相似文献   

8.
In order to demonstrate the potential to distinguish paratuberculosis (PTB) from bovine tuberculosis infection (TB), ELISAs with M. bovis-specific MPB70 or MPB83 as capture antigens were developed and tested on two groups of cattle: Group A comprised 23 animals positive for Mycobacterium avium paratuberculosis (Map) and TB free. Group B comprised 48 animals from a Map free herd during the previous 5 years, but confirmed as tuberculous by positive results on PPD testing and M. bovis culture. Results demonstrated a significant difference (p < 0.01) between reactivity of sera from these groups, encouraging the study of purified proteins to differentiate between both diseases.  相似文献   

9.
The principal surveillance tool used to control bovine tuberculosis in cattle is the removal of animals that provide a positive response to the tuberculin skin-test. In this study we performed a longitudinal investigation of the immunological and diagnostic consequences of repeated short-interval skin-tests in cattle naturally infected with Mycobacterium bovis. Tuberculin skin-test positive cattle were subjected to up to four further intradermal comparative cervical skin-tests at approximately 60-day intervals. A significant progressive reduction in the strength of the skin-test was observed after successive tests. In contrast, the magnitude of interferon-γ (IFN-γ) responses was not influenced by repeat skin-testing either transiently around the time of each skin-test or longitudinally following repeated tests. A significant boost in blood interleukin-10 (IL-10) production was observed within 3 days following each skin-test although the magnitude of this boosted response returned to lower levels by day 10 post-test. The application of a novel multiplex assay to simultaneously measure seven cytokines and chemokines also identified that skin-testing resulted in a significant and progressive reduction in antigen specific interleukin-1β (IL-1β) whilst confirming stable IFN-γ and elevated IL-10 responses in the blood. Therefore, we have demonstrated that in cattle naturally infected with M. bovis, repeat short-interval skin-testing can lead to a progressive reduction in skin-test responsiveness which has potential negative consequences for the detection of infected animals with marginal or inconclusive skin-test responses. The desensitising effect is associated with decreased IL-1β and elevated IL-10 responses, but importantly, does not influence antigen specific IFN-γ responses.  相似文献   

10.
This report describes an outbreak of Mycoplasma bovis mastitis affecting 45 cows in a herd of 122 dairy cattle in Northern Italy. Clinically, the outbreak was characterized by agalactia, multiple swollen and painless quarters, high milk somatic cell count and unresponsiveness to conventional antibiotic therapy. M. bovis was isolated from the milk samples of all the 32 affected cows tested and from the mammary tissue of three affected cows that underwent necropsy. No other pathogens were isolated from these samples. Lesions in two of the necropsied cows were characterized by mild chronic suppurative mastitis and galactophoritis. The other necropsied cow showed a chronic necrosuppurative and pyogranulamaous galactophoritis, a condition not previously associated with M. bovis. M. bovis was detected immunohistochemically in the lumen of the affected mammary ducts suggesting that ascending infection via the teat canal was the likely route of transmission. No other intralesional pathogens were demonstrated microscopically.  相似文献   

11.
The commercial LCx amplification assay, usually employed to detect the Myocobacterium tuberculosis complex in respiratory specimens, was evaluated by comparing the results it gave with those obtained using Löwenstein-Jensen solid medium and pathological findings on 55 lymph nodes from cattle with positive and 10 lymph nodes from cattle with negative skin tests for tuberculosis. Fifty-three cultures (51 and 2, respectively) were positive for M. bovis, while the results for the LCx assay and the histological method were positive in 48 (45, 3) and 24 (20, 4) samples, respectively. None of the samples from cattle from certified tuberculosis-free herds were positive by any of the procedures. The results obtained with the LCx assay, compared with the culture procedure, regarded as the gold standard among the diagnostic techniques, gave a specificity of 91.6% and sensitivity of 90.5%. Although the sensitivity of LCx was suboptimal, DNA of M. bovis was detected in 81.8% of the skin test-positive animals. Amplification techniques could provide a rapid and reasonably reliable tool for detecting bovine tuberculosis.  相似文献   

12.
Mycobacterium (M.) bovis, a bacterium in the M. tuberculosis complex, is a causative agent of bovine tuberculosis, a contagious disease of animals. Mycobacterial culture is the gold standard for diagnosing bovine tuberculosis, but this technique is laborious and time-consuming. In the present study, performance of the SD Bioline TB Ag MPT4 Rapid test, an immunochromatographic assay, was evaluated using reference bacterial strains and M. bovis field isolates collected from animals. The SD MPT64 Rapid test produced positive results for 95.5% (63/66) of the M. bovis isolates from cattle and 97.9% (46/47) of the isolates from deer. Additionally, the test had a sensitivity of 96.5% (95% CI, 91.2-99.0), specificity of 100% (95% CI, 96.7-100.0), positive predictive value of 100% (95% CI, 96.7-100.0), and negative predictive value of 92.9% (95% CI, 82.7-98.0) for M. bovis isolates. In conclusion, the SD MPT64 Rapid test is simple to use and may be useful for quickly confirming the presence of M. bovis in animals.  相似文献   

13.
The serological response to 12 purified Mycobacterium bovis antigens were examined in an ELISA assay. These antigens included the majority of M. bovis protein antigens described to date and in most cases they were very similar to the M. tuberculosis antigens of the same molecular mass.The purified antigens were tested against sera from M. bovis infected cattle, M. bovis culture-negative cattle from infected herds and animals infected with related microorganisms, mainly other mycobacterial species. All the antigens gave strong reactions with at least some sera from the M. bovis infected group and showed cross-reactivity with some of the sera from the other two groups. The antigen with the highest specificity reacted strongly with only 60% of the M. bovis infected sera. Antigens that reacted with most or all of the M. bovis infected sera also gave the highest cross-reactivity with sera from the other two groups. These results indicate that a serological test based on any one or a combination of these antigens, without removal of the cross-reacting epitopes, would be unsatisfactory.  相似文献   

14.
Mycoplasma bovis causes mastitis in dairy cows and is associated with pneumonia and polyarthritis in cattle. The present investigation included a retrospective case–control study to identify potential herd-level risk factors for M. bovis associated disease, and a prospective cohort study to evaluate the course of clinical disease in M. bovis infected dairy cattle herds in Switzerland. Eighteen herds with confirmed M. bovis cases were visited twice within an average interval of 75 d. One control herd with no history of clinical mycoplasmosis, matched for herd size, was randomly selected within a 10 km range for each case herd. Animal health data, production data, information on milking and feeding-management, housing and presence of potential stress- factors were collected. Composite quarter milk samples were aseptically collected from all lactating cows and 5% of all animals within each herd were sampled by nasal swabs. Organ samples of culled diseased cows were collected when logistically possible. All samples were analyzed by real-time polymerase chain reaction (PCR). In case herds, incidence risk of pneumonia, arthritis and clinical mastitis prior to the first visit and incidence rates of clinical mastitis and clinical pneumonia between the two visits was estimated. Logistic regression was used to identify potential herd-level risk factors for M. bovis infection. In case herds, incidence risk of M. bovis mastitis prior to the first visit ranged from 2 to 15%, whereas 2 to 35% of the cows suffered from clinical pneumonia within the 12 months prior to the first herd visit. The incidence rates of mycoplasmal mastitis and clinical pneumonia between the two herd visits were low in case herds (0–0.1 per animal year at risk and 0.1-0.6 per animal year at risk, respectively). In the retrospective-case-control study high mean milk production, appropriate stimulation until milk-let-down, fore-stripping, animal movements (cattle shows and trade), presence of stress-factors, and use of a specific brand of milking equipment, were identified as potential herd-level risk factors. The prospective cohort study revealed a decreased incidence of clinical disease within three months and prolonged colonization of the nasal cavity by M. bovis in young stock.  相似文献   

15.
Bovine tuberculosis is caused by Mycobacterium bovis, a mycobacterium highly similar to M. tuberculosis that belongs to the M. tuberculosis complex. The main host of M. bovis is cattle but it also affects many other mammalians including humans. Tuberculosis in humans caused by either M. bovis or M. tuberculosis is clinically hard to distinguish. During 2004–2005, samples from 448 patients with diagnosis of TB were collected from different regions of Argentina. The PRA technique identified 400 isolates with representative patterns of mycobacterium. The predominant ones were the M. tuberculosis complex, the M. avium–M. intracellulare complex and M. gordonae. Samples with M. tuberculosis complex PRA restriction profiles were analyzed with a multiplex PCR to differentiate between M. tuberculosis and M. bovis. Multiplex PCR identified nine M. bovis. The results allowed the possibility to establish that 2% of pulmonary tuberculosis was due to M. bovis. Isolates of M. bovis from humans were examined using spoligotyping. These isolates presented five different spoligotypes. The main spoligotype was also the most frequently one found in cattle. The remaining human spoligotypes (grouped in clusters) are occasionally found in cattle. Variable number tandem repeat (VNTR) analysis identified five different patterns. By combining the results of spoligotyping and VNTR analysis, we were able to differentiate seven M. bovis isolates. The remaining two M. bovis samples showed the same spoligotype and VNTR profile and belonged to household contacts. An MDR‐M. bovis was isolated from the samples of these household contacts. The identification of two epidemiologically linked cases of human M. bovis infection suggests person‐to‐person transmission of an MDR‐M. bovis.  相似文献   

16.
Tuberculosis (TB) represents a barrier for free trade of livestock between Mexico and the United States of America (US). In spite of efforts from Mexico to export TB-free animals, some of those found with TB lesions in slaughterhouses in the US are traced back to that country. Therefore, the purpose of this study was to determine, through molecular epidemiology, the most probable source of infection for cattle found with TB lesions in the US. Ninety M. bovis isolates, 50 from Mexico obtained from cattle in 8 different states, and 40 from the US from cattle, deer, elk and feral pigs from 7 different states were included in the study. All samples were analyzed in both laboratories, Mexico and the US, following the same protocol for molecular analysis by spoligotyping. Twenty-seven clusters, ranging from 1 to 18 genetically similar strains were found. Some clustering by country was observed, strains from cattle and deer in Michigan in the US fell into the same cluster, suggesting transmission between species. These results, combined with epidemiological information suggest that despite of the possibility that some animals with lesions in the US come from Mexico as false negatives, the US has its own source of infection, must probably in dairy cattle and wildlife. Genetic diversity of isolates from Mexico was larger than that in the US, which could be a consequence of the endemic status of the disease and the indiscriminate movement of animals between regions.  相似文献   

17.
Intra-specific diversity within Moraxella bovis was investigated analysing DNA fingerprints, outer membrane proteins (OMP) and lipopolysaccharides (LPS) profiles. Three collection strains and 57 isolates of M. bovis, collected during 3 years from cattle with infectious bovine keratoconjunctivitis (IBK) symptoms, from diverse geographical locations of Argentina, were examined. The LPS and OMP profiles were studied through SDS–PAGE analysis and genotype was determined by PCR-DNA fingerprinting. Genotyping identified five DNA types while analysis of LPS and OMP profiles identified three rough LPS types and three OMP types among the 60 isolates of M. bovis including the three collection strains. None of the three methods employed to assess diversity was discriminating when used alone because the degree of heterogeneity in each group of surface structures was limited, but when data of each typing method were combined, 15 distinct subgroups were determined. This subgrouping was clearly able to differentiate isolates of the same genotype. These typing methods appear to be useful to assess different aspects of the disease such as the diversity within a population of M. bovis associated to epidemic conditions, track the causal agent in an outbreak of the disease, monitoring vaccination programs and studies on virulence.  相似文献   

18.
Bovine tuberculosis (TB) is a major zoonosis that''s caused by Mycobacterium bovis (M. bovis). Being able to detect M. bovis is important to control bovine TB. We applied a molecular technique, the variable number tandem repeat (VNTR) typing method, to identify and distinguish the M. bovis isolates from Gyeonggi-do, Korea. From 2003 to 2004, 59 M. bovis clinical strains were isolated from dairy cattle in Gyeonggi-do, Korea, and these cattle had tuberculosis-like lesions. Twenty-four published MIRU-VNTR markers were applied to the M. bovis isolates and ten of them showed allelic diversity. The most discriminatory locus for the M. bovis isolates in Korea was QUB 3336 (h = 0.64). QUB 26 and MIRU 31 also showed high discriminative power (h = 0.35). The allelic diversity by the combination of all VNTR loci was 0.86. Six loci (MIRU 31, ETR-A and QUB-18, -26, -3232, -3336) displayed valuable allelic diversity. Twelve genotypes were identified from the 59 M. bovis isolates that originated from 20 cattle farms that were dispersed throughout the region of Gyenggi-do. Two genotypes [designation index (d.i.) = e, g] showed the highest prevalence (20% of the total farms). For the multiple outbreaks on three farms, two successive outbreaks were caused by the same genotype at two farms. Interestingly, the third outbreak at one farm was caused by both a new genotype and a previous genotype. In conclusion, this study suggests that MIRU-VNTR typing is useful to identify and distinguish the M. bovis isolates from Gyeonggi-do, Korea.  相似文献   

19.
After histopathological examination of a lesion found in a herd member returned a diagnosis of mycobacteriosis, a farmed herd (n = 47) of elk (Cervus elaphus nelsoni) and red deer (C. elaphus elaphus) was investigated for bovine tuberculosis with a battery of antemortem and postmortem diagnostic tests. Every animal was tested with the mid-cervical tuberculin skin test; all 47 had negative results. All of the 16 adult animals and 15 of the 31 calves (approximately 2-years-old) were blood-tested with a lymphocyte stimulation test (LST) and a fluorescence polarization assay (FPA), which detects antibody to the MPB70 protein antigen. At necropsy of the 31 blood-tested animals, tissues were harvested for histopathological examination and culture of mycobacteria. Mycobacterium bovis was isolated from 16 of the 31 animals, and a scotochromogen was also isolated from 1 of the 16 whose tissues yielded M. bovis. Each of these 16 animals, 15 of which were calves, also received a histopathological diagnosis of mycobacteriosis. Other species of mycobacteria, including those belonging to the M. avium and M. terrae complexes, were isolated from an additional 7 animals. The FPA was scored “positive” or “suspect” for 16 animals, 13 (81%) of which were culture-positive for M. bovis. The other 3 animals that were culture-positive for M. bovis had negative FPA results. Of the 3 FPA-positive or FPA-suspect animals that were culture-negative, 2 were suspected to have mycobacteriosis on the basis of the histopathological examination. The 7 animals from which Mycobacterium species other than M. bovis were cultured were all FPA-negative. The only animal with positive LST results was also FPA-positive and culture-positive for M. bovis. The M. bovis isolates had an identical spoligotype pattern, with an octal code of 664073777777600. This is the first report of the isolation and identification of this strain type in Canada.  相似文献   

20.
Tissue samples were collected at random from cattle (Bos taurus) and buffalo (Bubalus bubalis) from an abattoir of the district of Lahore and were analyzed for the presence of Mycobacterium avium subsp. paratuberculosis and Mycobacterium bovis through acid-fast staining and polymerase chain reaction (PCR). Body condition of animals and diarrhea were recorded. Most of the animals were emaciated. Diarrhea was noticed in 15.6% of buffaloes and 19.2% of cattle. Intestinal pathology was observed in 29% of buffaloes and 32.8% of cattle. Number of mesenteric lymph node (MLN) showing gross lesions was a bit higher (35.6%) in cattle than buffalo (31.2%). Acid-fast staining of tissue scraping smears revealed the presence of acid-fast bacilli (AFB) in 17.4% intestinal and 16.4% MLN tissue samples in buffalo, while in cattle 19.2% intestinal and 17.8% MLN were found positive for AFB. In buffaloes, PCR confirmed 12.8% intestinal and 12.4% MLN positive samples for M. avium subsp. paratuberculosis. However, in cattle, PCR analysis demonstrated 14.2% positive results for M. avium subsp. paratuberculosis in both MLN and intestinal tissue samples. PCR also confirmed M. bovis in 5.8% of cattle and 5% of buffalo MLN and intestinal tissues. PCR positive tissue samples for M. avium subsp. paratuberculosis were from those animals which were emaciated, having diarrhea, and severe gross lesions. AFB were also detected in tissue scraping smears of these animals. It is concluded that infection by various mycobacterium species can be differentiated by PCR, which is not possible by acid-fast staining technique.  相似文献   

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