Mycobacterium tuberculosis complex in wildlife: Review of current applications of antemortem and postmortem diagnosis (original) (raw)
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1Facts and dilemmas in diagnosis of tuberculosis in wildlife
2016
Mycobacterium bovis, causing bovine tuberculosis (BTB), has been recognized as a global threat at the wildlife-livestock-human interface, a clear “One Health ” issue. Several wildlife species have been identified as maintenance hosts. Spillover of infection from these species to livestock or other wildlife species may have economic and conservation implications and infection of humans causes public health concerns, especially in developing countries. Most BTB management strategies rely on BTB testing, which can be performed for a range of purposes, from disease surveillance to diagnosing individual infected animals. New diagnostic assays are being developed for selected wildlife species. This review investigates the most frequent objectives and associated requirements for testing wildlife for tuberculosis at the level of individual animals as well as small and large populations. By aligning those with the available (immunological) ante mortem diagnostic assays, the 2practical challe...
Pathogens, 2022
Despite the threat posed by tuberculosis (TB) to the protected European bison (Bison bonasus), no validated TB tests exist for this species. This pilot study evaluates two tests based on detecting cellular immunity for this purpose: interferon gamma release assay (IGRA) and tuberculin skin test (TST). Ten animals were subjected to ante-mortem and post-mortem examinations. IGRA was performed using a commercial test, and the comparative TST was performed in the eyelids. The lesions were assessed post-mortem and material was collected for mycobacterial culture. The isolated strains were subjected to genotyping. At post-mortem examination, five out of ten individuals demonstrated both tuberculous lesions and positive culture results (Mycobacterium caprae). Compared to the palpebral TST, the findings of the IGRA are easier to interpret when diagnosing tuberculosis in European bison.
Facts and dilemmas in diagnosis of tuberculosis in wildlife
Comparative Immunology, Microbiology and Infectious Diseases, 2013
Mycobacterium bovis, causing bovine tuberculosis (BTB), has been recognized as a global threat at the wildlife-livestock-human interface, a clear "One Health" issue. Several wildlife species have been identified as maintenance hosts. Spillover of infection from these species to livestock or practical challenges and limitations wildlife managers and researchers are currently faced with are highlighted.
Transboundary and Emerging Diseases, 2009
The infection of a variety of free-ranging wildlife species with Mycobacterium bovis, the causative agent of bovine tuberculosis (TB), can cause problems for biodiversity and species conservation. In some notable cases, particular species act as a reservoir of infection that can spill over into domestic livestock with economic and zoonotic consequences. Immunological methods for the detection of TB infection in wildlife are important for diagnostic and research purposes, especially where post-mortem examination is neither feasible nor desirable. In this review, the approaches taken to the immunological study of TB in wildlife species are summarized, with particular emphasis on their suitability for different applications and their applicability to different species. Different approaches to improving diagnostic sensitivity are discussed together with factors that can confound the use of tests in certain situations. Caution in the interpretation of test results for TB in wildlife is encouraged, especially where it has not been possible to confirm the accuracy of the test. This article, Review of the Diagnosis and Study of Tuberculosis in Non-Bovine Wildlife Species Using Immunological Methods, was written by M. A. Chambers of the TB Research Group, Department of Statutory and Exotic Bacterial Diseases. It is published with the permission of the Controller of HMSO and the Queenó s Printer for Scotland.
Diagnosis of tuberculosis in wildlife: a systematic review
Veterinary Research, 2021
Animal tuberculosis (TB) is a multi-host disease caused by members of the Mycobacterium tuberculosis complex (MTC). Due to its impact on economy, sanitary standards of milk and meat industry, public health and conservation, TB control is an actively ongoing research subject. Several wildlife species are involved in the maintenance and transmission of TB, so that new approaches to wildlife TB diagnosis have gained relevance in recent years. Diagnosis is a paramount step for screening, epidemiological investigation, as well as for ensuring the success of control strategies such as vaccination trials. This is the first review that systematically addresses data available for the diagnosis of TB in wildlife following the Preferred Reporting Items of Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The article also gives an overview of the factors related to host, environment, sampling, and diagnostic techniques which can affect test performance. After three screenings, 124 artic...
Indian Journal of Animal Sciences, 2022
The diagnosis of zoonotic tuberculosis revolves around detection of pathogen by gold standard culture method. In the live animals, tuberculin testing and interferon gamma assays are the options with their own limitation of specificity and cost effectiveness respectively. Clinical examination along with the affordable methods can lead to a definitive diagnosis which could help in decision making for not only the individual animal but also for the whole farm. During post-mortem examination, the post-mortem lesions with visible tubercle and acid fast staining give a fair idea of tuberculosis infected carcass for tuberculosis. The molecular testing of tissue samples with proven mycobacterial genus, Mycobacterium tuberculosis complex (which includes M. bovis also) and M. bovis speciesspecific primers can add to the diagnostic strength for bovine tuberculosis. In this regard, we evaluated sequential PCRs for mycobacterial genus specific primer (hsp65), M. tuberculosis complex specific primer (IS6110 & IS1081) and M. bovis specific primer (RD4 and 500 bp) in spiked and field tissue samples of cattle. The research was carried out in 2019-20 in Division of Animal Health for framing out a diagnostic confirmation protocol for TB infected cattle on tissue samples. All the PCR assays were almost equally efficient in detection of M. bovis in spiked samples, if supported by an efficient DNA extraction method which is the foremost limiting factor. It was concluded that a combination of minimum of two assays can give a definitive result along with the support of the clinical history or post mortem outcome of the animals.
Journal of Veterinary Diagnostic Investigation, 2011
Abstract. In the United States, tuberculosis of captive cervids, caused by Mycobacterium bovis, attracted attention in 1991 when investigations, prompted by the identification of a tuberculous elk (Cervus elaphus nelsoni) of U.S. origin exported to Canada, revealed tuberculosis in 10 different elk herds in 8 different states. Based on methods used in cattle, official regulations pertaining to testing and eradication of tuberculosis in captive cervids were added to the U.S. Department of Agriculture bovine tuberculosis eradication effort in 1994. However, little published information exists on the accuracy of intradermal tuberculin testing in naturally infected cervids. Evaluation of a captive herd of 71 animals in Wisconsin included postmortem examination and tissue sample collection from both tuberculin test responders and nonresponders. Within this captive herd, of admittedly small size, results showed the single cervical test to have a sensitivity of 88% and a specificity of 69%. Evaluation of diagnostic tests in the species of interest is important, as extrapolation of data obtained from other species may not be appropriate.
1996
Using the isolation of Mycobacterium bovis as the reference standard, this study evaluated the sensitivity, specificity and kappa statistic of gross pathology (abattoir postmortem inspection), histopathology, and parallel or series combinations of the two for the diagnosis of tuberculosis in 430 elk and red deer. Two histopathology interpretations were evaluated: histopathology I, where the presence of lesions compatible with tuberculosis was considered positive, and histopathology II, where lesions compatible with tuberculosis or a select group of additional possible diagnoses were considered positive. In the 73 animals from which M. bovis was isolated, gross lesions of tuberculosis were most often in the lung (48), the retropharyngeal lymph nodes (36), the mesenteric lymph nodes (35), and the mediastinal lymph nodes (16). Other mycobacterial isolates included: 11 M. paratuberculosis, 11 M. avium, and 28 rapidly growing species or M. terrae complex. The sensitivity estimates of gross pathology and histopathology I were 93% (95% confidence limits [CL] 84,97%) and 88% [CL 77,94%], respectively, and the specificity of both was 89% [CL 85,92%]). The sensitivity and specificity of histopathology II were 89% (CL 79,95%) and 77% (CL 72,81%), respectively. The highest sensitivity estimates (93-95% [CL 84,98%]) were obtained by interpreting gross pathology and histopathology in parallel (where an animal had to be positive on at least one of the two, to be classified as combination positive). The highest specificity estimates (94-95% [CL 91-97%]) were generated when the two tests were interpreted in series (an animal had to be positive on both tests to be classified as combination positive). The presence of gross or microscopic lesions showed moderate to good agreement with the isolation of M. bovis (Kappa = 65-69%). The results show that post-mortem inspection, histopathology and culture do not necessarily recognize the same infected animals and that the spectra of animals identified by the tests overlaps.
Research in Veterinary Science, 2006
The early, preclinical stages of bovine TB can be detected in live animals by the use of tests of cellular immunity (the skin, c-interferon and lymphocyte transformation tests). Tests of humoral (antibody) immunity, Mycobacterium bovis PCR probes on early tissue cultures or live cattle specimens, and tests based on ‘‘electronic nose’’ technology have been developed more recently. The key measure of diagnostic test accuracy is the relationship between sensitivity and specificity, which determines the false-positive and false-negative proportions. None of the tests currently available for the diagnosis of bovine TB allow a perfectly accurate determination of the M. bovis infection status of cattle. Although various factors can reduce the sensitivity and specificity of the skin tests, these remain the primary ante mortem diagnostic tools for TB in cattle, providing a cost-effective and reliable means of screening entire cattle populations. Despite the inescapable limitations of existing diagnostic tests, bovine TB has been effectively eradicated from many developed countries and regions with the implementation of sound programmes of regular tuberculin skin testing and removal of reactors, coupled with slaughterhouse surveillance for undetected infections, repeat testing and culling of infected herds, cattle movement restrictions to prevent introduction of infected animals and occasional slaughter of entire herds with intractable breakdowns. This is likely to remain the mainstay of bovine TB control programmes for the foreseeable future. Additionally, newer ancillary in vitro diagnostic assays are now available to TB control programme managers to supplement the skin tests in defined circumstances according to the specific disease situation in each country or region. The strategic deployment of ancillary in vitro tests alongside the primary skin tests has enhanced the detection of M. bovis-infected cattle and reduced the number of animals slaughtered as false positives.
Canadian journal of veterinary research = Revue canadienne de recherche vétérinaire, 1996
Using the isolation of Mycobacterium bovis as the reference standard, this study evaluated the sensitivity, specificity and kappa statistic of gross pathology (abattoir postmortem inspection), histopathology, and parallel or series combinations of the two for the diagnosis of tuberculosis in 430 elk and red deer. Two histopathology interpretations were evaluated: histopathology I, where the presence of lesions compatible with tuberculosis was considered positive, and histopathology II, where lesions compatible with tuberculosis or a select group of additional possible diagnoses were considered positive. In the 73 animals from which M. bovis was isolated, gross lesions of tuberculosis were most often in the lung (48), the retropharyngeal lymph nodes (36), the mesenteric lymph node (35), and the mediastinal lymph nodes (16). Other mycobacterial isolates included: 11 M. paratuberculosis, 11 M. avium, and 28 rapidly growing species or M. terrae complex. The sensitivity estimates of gros...