scholarly journals Performance of the Enferplex TB Assay with Cattle in Great Britain and Assessment of Its Suitability as a Test To Distinguish Infected and Vaccinated Animals

2010 ◽  
Vol 17 (5) ◽  
pp. 813-817 ◽  
Author(s):  
Clare Whelan ◽  
Adam O. Whelan ◽  
Eduard Shuralev ◽  
Hang Fai Kwok ◽  
Glyn Hewinson ◽  
...  
Keyword(s):  
Great Britain ◽  
Mycobacterium Bovis ◽  
Bovine Tuberculosis ◽  
Serological Test ◽  
Relative Sensitivity ◽  
Multiplex Assay ◽  
Screening Methods ◽  
Sensitivity Range ◽  
Test Specificity ◽  
Serology Test

ABSTRACT Rapid, simple, and accurate antemortem tests for tuberculosis (TB) in cattle need to be developed in order to augment the existing screening methods. In particular, as cattle vaccines are developed, such tests would allow the continuation of test-and-slaughter policies alongside vaccination. Therefore, the development of an assay that distinguishes infected from vaccinated animals (a DIVA test) is an urgent research requirement. In this study, we assessed the performance of a novel multiplex serological test with sera collected from 96 skin-tested animals with bovine tuberculosis, 93 TB-free animals, and 39 cattle vaccinated with Mycobacterium bovis BCG. Our results indicate that the test has a relative sensitivity range of 77.0% to 86.5% at corresponding specificity levels of 100.0% to 77.6%. Comparison with the Bovigam gamma interferon antemortem test revealed that this serology test was significantly more sensitive at specificities above 97.9%, while the Bovigam test was, on average, about 10% more sensitive when the test specificity was set below 97%. Importantly, this serological multiplex assay does not react with sera from BCG-vaccinated calves and is therefore suitable as a DIVA test alongside BCG-based vaccine strategies.

scholarly journals The last outbreak of bovine tuberculosis in cattle in the CzechRepublic in 1995 was caused by Mycobacterium bovis subspecies caprae

2012 ◽  
Vol 47 (No. 9) ◽  
pp. 251-263 ◽  
Author(s):  
I. Pavlik ◽  
F. Bures ◽  
P. Janovsky ◽  
P. Pecinka ◽  
M. Bartos ◽  
...  
Keyword(s):  
Great Britain ◽  
Mycobacterium Bovis ◽  
Cervus Elaphus ◽  
Bovine Tuberculosis ◽  
Red Deer ◽  
Post Mortem ◽  
Biochemical Tests ◽  
Source Of Infection ◽  
Three Samples ◽  
Green Fodder

The last outbreak of bovine tuberculosis in cattle in the CzechRepublic was detected in 1995. Signs of diarrhoea, weight loss and occasional coughing appeared in one 14-year-old cow after giving birth for the thirteenth time. Two months after these symptoms had been observed, it had to be slaughtered and numerous tuberculous lesions were found in its lung tissue, including the pleura. Within three months after the confirmation of the infection and consecutive intra-vitam and post-mortem diagnostics, all 28 remaining head of cattle from the herd (nine cows, seven bulls, six heifers and six calves) and five pigs were slaughtered. Patho-anatomical lesions were detected in all animals indicative of tuberculosis, from which Mycobacterium bovis was cultured and identified on the basis of biochemical tests and virulence test in a guinea-pig. The culture of 33 samples of other biological material than tissues (milk and urine of cows, feeding water, scrapings from the shed, fodder and others) resulted in M. bovis being detected in three samples (scrapings from shed walls). By the spoligotyping method M. bovis subsp. caprae was found in six selected isolates originating from two cows, two heifers and two bulls. It may therefore be assumed that there was one source of infection in the herd, which was the first infected old cow. In comparison with 3 176 spoligotypes in the existing database RIVM (National Institute of Public Health and the Environment, Bilthoven, The Netherlands) and literary data it was found that this spoligotype was also found in Sweden, Belgium, Great Britain, Spain, Poland, Germany and the CzechRepublic. It was impossible to determine the source of M. bovis subsp. caprae of the first infected cow on the basis of results from database and from anamnestic data. Green fodder coming from the farmer’s pastures near a forest could be considered as a possible source of M. bovis from wild ruminants like red deer (Cervus elaphus), which was found infected with bovine tuberculosis in another district of the CzechRepublic in 1991.

scholarly journals Serological test performance for bovine tuberculosis in cattle from herds with evidence of on-going infection in Northern Ireland

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0245655
Author(s):  
Lyanne McCallan ◽  
Cathy Brooks ◽  
Claire Barry ◽  
Catherine Couzens ◽  
Fiona J. Young ◽  
...  
Keyword(s):  
Northern Ireland ◽  
Test Performance ◽  
Bovine Tuberculosis ◽  
Serological Test ◽  
Infected Individual ◽  
Post Mortem ◽  
Serological Tests ◽  
Discriminatory Ability ◽  
Serology Test

The ability to accurately identify infected hosts is the cornerstone of effective disease control and eradication programs. In the case of bovine tuberculosis, accurately identifying infected individual animals has been challenging as all available tests exhibit limited discriminatory ability. Here we assess the utility of two serological tests (IDEXX Mycobacterium bovis Ab test and Enfer multiplex antibody assay) and assess their performance relative to skin test (Single Intradermal Comparative Cervical Tuberculin; SICCT), gamma-interferon (IFNγ) and post-mortem results in a Northern Ireland setting. Furthermore, we describe a case-study where one test was used in conjunction with statutory testing. Serological tests using samples taken prior to SICCT disclosed low proportions of animals as test positive (mean 3% positive), despite the cohort having high proportions with positive SICCT test under standard interpretation (121/921; 13%) or IFNγ (365/922; 40%) results. Furthermore, for animals with a post-mortem record (n = 286), there was a high proportion with TB visible lesions (27%) or with laboratory confirmed infection (25%). As a result, apparent sensitivities within this cohort was very low (≤15%), however the tests succeeded in achieving very high specificities (96–100%). During the case-study, 7/670 (1.04%) samples from SICCT negative animals from a large chronically infected herd were serology positive, with a further 17 animals being borderline positive (17/670; 2.54%). Nine of the borderline animals were voluntarily removed, none of which were found to be infected post-mortem (no lesions/bacteriology negative). One serology test negative animal was subsequently found to have lesions at slaughter with M. bovis confirmed in the laboratory.

scholarly journals Immune Responses to Defined Antigens of Mycobacterium bovis in Cattle Experimentally Infected with Mycobacterium kansasii

2006 ◽  
Vol 13 (6) ◽  
pp. 611-619 ◽  
Author(s):  
W. R. Waters ◽  
M. V. Palmer ◽  
T. C. Thacker ◽  
J. B. Payeur ◽  
N. B. Harris ◽  
...  
Keyword(s):  
Mycobacterium Bovis ◽  
Bovine Tuberculosis ◽  
Nontuberculous Mycobacteria ◽  
Gamma Interferon ◽  
Delayed Type Hypersensitivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Antibodies ◽  
Specific Serum ◽  
Specific Proteins

ABSTRACT Cross-reactive responses elicited by exposure to nontuberculous mycobacteria often confound the interpretation of antemortem tests for Mycobacterium bovis infection of cattle. The use of specific proteins (e.g., ESAT-6, CFP-10, and MPB83), however, generally enhances the specificity of bovine tuberculosis tests. While genes for these proteins are absent from many nontuberculous mycobacteria, they are present in M. kansasii. Instillation of M. kansasii into the tonsillar crypts of calves elicited delayed-type hypersensitivity and in vitro gamma interferon and nitrite concentration responses of leukocytes to M. avium and M. bovis purified protein derivatives (PPDs). While the responses of M. kansasii-inoculated calves to M. avium and M. bovis PPDs were approximately equivalent, the responses of M. bovis-inoculated calves to M. bovis PPD exceeded their respective responses to M. avium PPD. The gamma interferon and nitrite responses of M. kansasii-inoculated calves to recombinant ESAT-6-CFP-10 (rESAT-6-CFP-10) exceeded corresponding responses of noninoculated calves as early as 15 and 30 days after inoculation, respectively, and persisted throughout the study. The gamma interferon and nitrite responses of M. bovis-inoculated calves to rESAT-6-CFP-10 exceeded the corresponding responses of M. kansasii-inoculated calves beginning 30 days after inoculation. By using a lipoarabinomannan-based enzyme-linked immunosorbent assay, specific serum antibodies were detected as early as 50 days after challenge with M. kansasii. By a multiantigen print immunoassay and immunoblotting, serum antibodies to MPB83, but not ESAT-6 or CFP-10, were detected in M. kansasii-inoculated calves; however, responses to MPB83 were notably weaker than those elicited by M. bovis infection. These findings indicate that M. kansasii infection of calves elicits specific responses that may confound the interpretation of bovine tuberculosis tests.

scholarly journals Use of ethanol extract of Mycobacterium bovis for detection of specific antibodies in sera of farmed red deer (Cervus elaphus) with bovine tuberculosis

2013 ◽  
Vol 9 (1) ◽  
pp. 256 ◽  
Author(s):  
Ashutosh Wadhwa ◽  
Rachel E Johnson ◽  
Colin G Mackintosh ◽  
J Frank T Griffin ◽  
W Waters ◽  
...  
Keyword(s):  
Mycobacterium Bovis ◽  
Cervus Elaphus ◽  
Bovine Tuberculosis ◽  
Red Deer ◽  
Ethanol Extract ◽  
Specific Antibodies

scholarly journals Bovine Tuberculosis (Mycobacterium bovis) Outbreak Duration in Cattle Herds in Ireland: A Retrospective Observational Study

Pathogens ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 815
Author(s):  
Andrew W. Byrne ◽  
Damien Barrett ◽  
Philip Breslin ◽  
Jamie M. Madden ◽  
James O'Keeffe ◽  
...  
Keyword(s):  
Risk Factors ◽  
Observational Study ◽  
Mycobacterium Bovis ◽  
Bovine Tuberculosis ◽  
Animal Health ◽  
Herd Size ◽  
Policy Formation ◽  
Nitrogen Loading ◽  
Management Policy ◽  
Retrospective Observational Study

Bovine tuberculosis (bTB) outbreaks, caused by Mycobacterium bovis infection, are a costly animal health challenge. Understanding factors associated with the duration of outbreaks, known as breakdowns, could lead to better disease management policy development. We undertook a retrospective observational study (2012–2018) and employed Finite Mixture Models (FMM) to model the outcome parameter, and to investigate how factors were associated with duration for differing subpopulations identified. In addition to traditional risk factors (e.g., herd size, bTB history), we also explored farm geographic area, parcels/farm fragmentation, metrics of intensity via nitrogen loading, and whether herds were designated controlled beef finishing units (CBFU) as potential risk factors for increased duration. The final model fitted log-normal distributions, with two latent classes (k) which partitioned the population into a subpopulation around the central tendency of the distribution, and a second around the tails of the distribution. The latter subpopulation included longer breakdowns of policy interest. Increasing duration was positively associated with recent (<3 years) TB history and the number of reactors disclosed, (log) herd size, beef herd-type relative to other herd types, number of land parcels, area, being designated a CBFU (“feedlot”) and having high annual inward cattle movements within the “tails” subpopulation. Breakdown length was negatively associated with the year of commencement of breakdown (i.e., a decreasing trend) and non-significantly with the organic nitrogen produced on the farm (N kg/hectare), a measure of stocking density. The latter finding may be due to confounding effects with herd size and area. Most variables contributed only moderately to explaining variation in breakdown duration, that is, they had moderate size effects on duration. Herd-size and CBFU had greater effect sizes on the outcome. The findings contribute to evidence-based policy formation in Ireland.

scholarly journals High variability in transmission of SARS-CoV-2 within households and implications for control

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0259097
Author(s):  
Damon J. A. Toth ◽  
Alexander B. Beams ◽  
Lindsay T. Keegan ◽  
Yue Zhang ◽  
Tom Greene ◽  
...  
Keyword(s):  
Test Data ◽  
Attack Rate ◽  
Serological Test ◽  
Close Contact ◽  
Antibody Test ◽  
High Variability ◽  
Test Accuracy ◽  
Household Transmission ◽  
Wide Range ◽  
Test Specificity

Background Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) poses a high risk of transmission in close-contact indoor settings, which may include households. Prior studies have found a wide range of household secondary attack rates and may contain biases due to simplifying assumptions about transmission variability and test accuracy. Methods We compiled serological SARS-CoV-2 antibody test data and prior SARS-CoV-2 test reporting from members of 9,224 Utah households. We paired these data with a probabilistic model of household importation and transmission. We calculated a maximum likelihood estimate of the importation probability, mean and variability of household transmission probability, and sensitivity and specificity of test data. Given our household transmission estimates, we estimated the threshold of non-household transmission required for epidemic growth in the population. Results We estimated that individuals in our study households had a 0.41% (95% CI 0.32%– 0.51%) chance of acquiring SARS-CoV-2 infection outside their household. Our household secondary attack rate estimate was 36% (27%– 48%), substantially higher than the crude estimate of 16% unadjusted for imperfect serological test specificity and other factors. We found evidence for high variability in individual transmissibility, with higher probability of no transmissions or many transmissions compared to standard models. With household transmission at our estimates, the average number of non-household transmissions per case must be kept below 0.41 (0.33–0.52) to avoid continued growth of the pandemic in Utah. Conclusions Our findings suggest that crude estimates of household secondary attack rate based on serology data without accounting for false positive tests may underestimate the true average transmissibility, even when test specificity is high. Our finding of potential high variability (overdispersion) in transmissibility of infected individuals is consistent with characterizing SARS-CoV-2 transmission being largely driven by superspreading from a minority of infected individuals. Mitigation efforts targeting large households and other locations where many people congregate indoors might curb continued spread of the virus.

scholarly journals Improvement of bovine tuberculosis diagnosis

2021 ◽  
pp. 261-265
Author(s):  
M. O. Baratov
Keyword(s):  
Red Blood Cells ◽  
Mycobacterium Bovis ◽  
Blood Cells ◽  
Bovine Tuberculosis ◽  
Intradermal Test ◽  
Mycobacterium Fortuitum ◽  
Post Mortem ◽  
Post Mortem Examination ◽  
Antibody Titers ◽  
Specific Reactions

Detection of animals with non-specific reactions to tuberculin is one of the major problems in bovine tuberculosis (TB) diagnosis. There is a need to find and improve methods for detection of the sensitization causes. This paper presents the results of comparative studies of different ways to stabilize red blood cells in order to obtain diagnosticums for indirect hemagglutination (IHA) test. The article describes the stages of red blood cells stabilization and sensitization and demonstrates the diagnostic significance of Fili stabilization method using formaldehyde as a fixative. The highest antibody titers (1:3000 and 1:4000) were received in hyperimmune sera of rabbits immunized with Mycobacterium bovis using a homologous diagnosticum. Practical importance of the sensitins homologous to the infection is shown during testing of 1,911 serum samples collected from animals of different categories (diseased; healthy and reacting to tuberculin; healthy and not reacting to tuberculin) with IHA test using diagnosticums produced from Mycobacterium bovis and Mycobacterium fortuitum. Based on the positive results of the IHA test, TB was diagnosed in 87.5% of animals originating from an infected farm during post-mortem examination. The results of the IHA test agreed with those of the intradermal tuberculin test in 37.7% of cases. Diagnostic antibody titers were found in 206 TB infected animals with no reaction to the intradermal test. However, the post-mortem examination revealed TB changes in internal organs. The obtained data suggest a possibility to use the IHA test to detect TB infected animals with non-specific reactions to tuberculin.

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