Estimating the true prevalence of Mycobacterium bovis in free-ranging elk in Michigan

Although relatively small, Michigan's elk (Cervus elaphus nelsoni) herd is highly valued by both hunters and the general public. Elk and red deer (Cervus elaphus elaphus) are highly susceptible to infection with Mycobacterium bovis, the causative agent of bovine tuberculosis (TB), and outbreaks have been documented worldwide. The Michigan elk range lies entirely within counties where TB is known to be enzootic in white-tailed deer (Odocoileus virginianus). Consequently, a project was undertaken to estimate the true prevalence of TB in Michigan's free-ranging elk herd. All elk harvested by licensed hunters during 2002-2004, and all nonharvest elk mortalities examined by the Michigan Department of Natural Resources Wildlife Disease Laboratory from November 2002-May 2005, were screened for gross lesions of TB with samples of cranial lymph nodes and palatine tonsils collected for histopathology and mycobacterial culture. In all, 334 elk were included in the study. Twenty-three elk with gross lesions were considered TB suspects; all were culture-negative for M. bovis. However, M. bovis was cultured from two elk without gross lesions. The sensitivity, specificity, and negative predictive value of the current TB surveillance protocol were 0%, 100%, and 99.4%, respectively, while the apparent prevalence and true prevalence calculated directly from the sample were 0% and 0.6%, respectively. The positive predictive value and the estimated true prevalence of the population were undefined. The poor sensitivity of current surveillance was likely an artifact of its application to a relatively small sample, in order to detect a disease present at very low prevalence. The low prevalence of TB in Michigan elk, and the early stage of pathogenesis of the few infected animals, does not suggest elk are maintenance hosts at the present time.     

Survival of Mycobacterium bovis on feedstuffs commonly used as supplemental feed for white-tailed deer (Odocoileus virginianus)

Mycobacterium bovis, the causative agent of bovine tuberculosis, has become established in free-ranging white-tailed deer Odocoileus virginianus in northeastern Michigan. The practice of supplemental feeding of white-tailed deer during the winter is believed to contribute to transmission of M. bovis between deer. The current study was conducted to determine the ability of M. bovis to survive on various feedstuffs commonly used as supplemental feed for deer in northeast Michigan (i.e., apples, corn, carrots, sugar beets, potatoes, and hay) and the effect of maintenance at -20 C, 8 C, and 23 C on survival. Mycobacterium bovis survived on all feedstuffs at all temperatures tested for at least 7 days. At 23 C, M. bovis could still be isolated from samples of apples, corn and potatoes at 112 days. This study suggests that contamination of feedstuffs by M. bovis-infected deer could act as a source of indirect transmission between deer because M. bovis is able to survive in temperatures similar to those recorded during winter months in northeastern Michigan. Current efforts to ban or control supplemental feeding of deer should have a positive effect on decreasing transmission of M. bovis among deer.     

Bovine tuberculosis in free-ranging carnivores from Michigan

During a survey of carnivores and omnivores for bovine tuberculosis conducted in Michigan (USA) since 1996, Mycobacterium bovis was cultured from lymph nodes pooled from six coyotes (Canis latrans) (four adult female, two adult male), two adult male raccoons (Procyon lotor), one adult male red fox (Vulpes vulpes), and one 1.5-yr-old male black bear (Ursus americanus). One adult, male bobcat (Felis rufus) with histologic lesions suggestive of tuberculosis was negative on culture but positive for organisms belonging to the Mycobacterium tuberculosis complex when tested by polymerase chain reaction. All the tuberculous animals were taken from three adjoining counties where M. bovis is known to be endemic in the free-ranging white-tailed deer (Odocoileus virginianus) population. There were two coyotes, one raccoon, one red fox, and one bobcat infected in Alpena county. Montmorency County had two coyotes and one raccoon with M. bovis. Two coyotes and a bear were infected from Alcona County. These free-ranging carnivores/omnivores probably became infected with M. bovis through consumption of tuberculous deer. Other species included in the survey were opossum (Didelphis virginiana), gray fox (Urocyon cinereoargenteus), and badger (Taxidea taxus); these were negative for M. bovis.     

Aerosol exposure of white-tailed deer (Odocoileus virginianus) to Mycobacterium bovis

Tuberculosis due to Mycobacterium bovis affects both captive and free-ranging Cervidae in the United States. Various animal models have been developed to study tuberculosis of both humans and animals. Generally, tuberculosis is transmitted by aerosol and oral routes. Models of aerosol exposure of large animals to M. bovis are uncommon. In order to develop a reliable method of aerosol exposure of white-tailed deer (Odocoileus virginianus) to M. bovis, 12 healthy white-tailed deer, aged 8-10 mo, were infected by aerosol exposure to 2 x 10(5) to 1 x 10(6) colony forming units (CFU) (high close, n = 4) of M. bovis or 6 x 10(2) to 1.6 x 10(3) CFU (low dose, n = 8) of M. bovis. Tuberculous lesions were more widely disseminated in (leer receiving the high dose, while lesions in deer receiving the low dose were more focused on the lungs and associated lymph nodes (tracheobronchial and mediastinal). Aerosol delivery of M. bovis to white-tailed deer results in a reliable manner of experimental infection that may be useful for studies of disease pathogenesis, immune response, mycobacterial shedding, and vaccine efficacy.     

Evaluation of the influence of supplemental feeding of white-tailed deer (Odocoileus virginianus) on the prevalence of bovine tuberculosis in the Michigan wild deer population

A retrospective study was conducted to test the hypothesis that supplemental feeding of white-tailed deer (Odocoileus virginianus) from 1995 to 1997 was associated with the prevalence of bovine tuberculosis (TB) in free-ranging deer in northeastern Michigan.Bovine TB prevalence data were obtained from an ongoing surveillance program, while data relating to supplemental feeding and other risk factors were collected via in-person interviews. A multivariable Poisson regression modeling approach was used to test the stated hypothesis while controlling for other risk factors. Of the 389 potential participants, 59% agreed to participate in the study. Results showed that supplemental feeding of deer was associated with bovine TB in white-tailed deer. Specific risk factors associated with increasing risk for bovine TB were locating feed sites in areas with high levels of hardwood forests (O.R. = 1.8, 95% C.I. = 1.3-2.4), other large-scale feeding sites in the area (O.R. = 1.1, 95% C.I. = 1.0-1.2), the number of deer fed per year (O.R. = 3.9, 95% C.I. = 1.4-11.4), the numbers of feed sites spreading grain (O.R. = 14.7, 95% C.I. = 2.2-98.9), the quantity of grains provided at the site (O.R. = 1.4, 95% C.I. = 1.1-1.7), and the quantity of fruits and vegetables provided (O.R. = 1.4, 95% C.I. = 1.2-1.7). Conversely, factors associated with decreasing risk of bovine TB were locating feed sites in areas with high levels of hardwood forests (O.R. = 0.1, 95% C.I. = 0.02-0.4), locating feed sites in forests (O.R. = 0.05, 95% C.I. = 0.01-0.4), and the level of sites providing grain (O.R. = 0.1, 95% C.I. = 0.01-0.3). The results of this study suggest that banning the practice of supplemental feeding is a valid policy for control of bovine tuberculosis in free-ranging white-tailed deer.     

Seroprevalence and risk factors associated to Mycobacterium bovis in wild artiodactyl species from southern Spain, 2006-2010

The control of bovine tuberculosis (bTB) is at a critical point in the last stage of eradication in livestock. Wildlife species recently have emerged infected with TB in Europe, particularly ungulates in the Iberian Peninsula. Epidemiological information regarding TB in wild ungulates including affected species, prevalence, associated risk factors and appropriate diagnostic methods need to be obtained in these countries. A cross-sectional study was carried out on wild artiodactyl species, including Eurasian wild boar (Sus scrofa) red deer (Cervus elaphus), roe deer (Capraelus capraelus), fallow deer (Dama dama), Spanish ibex (Capra pyrenaica hispanica) and mouflon (Ovis musimon), in Spain to assess the seroprevalence against Mycobacterium bovis or cross-reacting members of the Mycobcaterium tuberculosis complex (MTBC), and to provide information on associated risk factors. Previously, two in-house indirect enzyme linked immunosorbent assays (bPPD-ELISA and MPB83-ELISA) were developed using known TB status sera. Positive reference sera were selected from infected animals confirmed by culture. The M. bovis isolates belonged to spoligotypes SB0121, SB0120, SB0295, SB0265 and SB0134. Two hundred and two out of 1367 (7.5%; 95% CI: 6.1-8.9) animals presented antibodies against M. bovis by both bPPD-ELISA and MPB83-ELISA. Significantly higher TB seroprevalence was observed in wild boar compared to the other species analyzed. Interestingly, seropositivity against M. bovis was not found in any out of 460 Spanish ibex analyzed. The logistic regression model for wild boar indicated that the seropositivity to M. bovis was associated with age, location and year of sampling, while the only risk factor associated with M. bovis seroprevalence in red deer and fallow deer was the age. The seroprevalence observed indicates a widespread exposure to MTBC in several wild artiodactyl species in southern Spain, which may have important implications not only for conservation but also for animal and public health.     

Mycobacterium bovis in wildlife in France

In early 2001, tuberculosis-like lesions were detected in three hunter-killed red deer (Cervus elaphus) in the Brotonne Forest (Normandy, France), and Mycobacterium bovis was isolated. In subsequent hunting seasons, two surveys were conducted in the area. In the first survey (2001-02 hunting season), nine (13%) of 72 red deer sampled were positive for M. bovis. In the 2005-06 hunting season, the prevalence of M. bovis infection increased to 24% (chi2=3.85, df=1, P=0.05; 33 positive among 138 sampled). The prevalence remained stable in juveniles, but it increased significantly in adults: from 13% in 2001-02 to 32% in 2005-06 (chi2=5.13, df=1, P=0.02). Wild boar (Sus scrofa) were heavily infected in both surveys. One roe deer (Capreolus capreolus) and one red fox (Vulpes vulpes) also tested positive in the second survey. Mycobacterium bovis was not isolated from Eurasian badgers (Meles meles). Spoligotyping and mycobacterial interspersed repetitive unit-variable number tandem repeat analysis demonstrated that all M. bovis strains isolated from wildlife were of the same genotype. Thus, the wildlife outbreak involved only a single strain, and this strain was the same as that circulating in nearby cattle herds since 1995. Sensitivity, specificity, and predictive values of the presence of macroscopic lesions as a diagnostic criterion were evaluated from the data obtained from red deer. Necropsy seems to be satisfactory as a routine tool to monitor the disease in wild red deer populations in which bovine tuberculosis has become established.     

Prevalence of chronic wasting disease and bovine tuberculosis in free-ranging deer and elk in South Dakota

Heads of hunter-harvested deer and elk were collected throughout South Dakota (USA) and within established chronic wasting disease (CWD) surveillance areas from 1997-2002 to determine infection with CWD and bovine tuberculosis (TB). We used immunohistochemistry to detect CWD-infected individuals among 1,672 deer and elk sampled via geographically targeted surveillance. A total of 537 elk (Cervus elaphus nelsoni), 813 white-tailed deer (Odocoileus virginianus), and 322 mule deer (O. hemionus) was sampled for CWD. Estimated overall prevalence and associated confidence intervals (95%) in white-tailed deer was 0.001% (0-0.007%). Similarly, estimated overall prevalence in elk and mule deer was 0.0% (0-0.004%) and 0.0% (0-0.011%), respectively. A total of 401 elk, 1,638 white-tailed deer, and 207 mule deer was sampled for TB. Estimated overall prevalence of infection with TB in elk harvested in South Dakota was 0.0% (0-0.009%). Similarly, estimated overall prevalence of TB in white-tailed deer and mule deer harvested throughout South Dakota was 0.0% (0-0.002%) and 0.0% (0-0.018%), respectively.     

Early detection of chronic wasting disease prions in urine of pre-symptomatic deer by real-time quaking-induced conversion assay

Chronic wasting disease (CWD) is a prion disease of captive and free-ranging deer (Odocoileus spp), elk (Cervus elaphus nelsonii) and moose (Alces alces shirasi). Unlike in most other prion diseases, in CWD prions are shed in urine and feces, which most likely contributes to the horizontal transmission within and between cervid species. To date, CWD ante-mortem diagnosis is only possible by immunohistochemical detection of protease resistant prion protein (PrP^Sc) in tonsil or recto-anal mucosa-associated lymphoid tissue (RAMALT) biopsies, which requires anesthesia of animals. We report on detection of CWD prions in urine collected from pre-symptomatic deer and in fecal extracts by using real time quaking-induced conversion (RT-QuIC). This assay can be useful for non-invasive pre-symptomatic diagnosis and surveillance of CWD.     

A Bayesian approach to study the risk variables for tuberculosis occurrence in domestic and wild ungulates in South Central Spain

ABSTRACT: BACKGROUND: Bovine tuberculosis (bTB) is a chronic infectious disease mainly caused by Mycobacterium bovis. Although eradication is a priority for the European authorities, bTB remains active or even increasing in many countries, causing significant economic losses. The integral consideration of epidemiological factors is crucial to more cost-effectively allocate control measures. The aim of this study was to identify the nature and extent of the association between TB distribution and a list of potential risk factors regarding cattle, wild ungulates and environmental aspects in Ciudad Real, a Spanish province with one of the highest TB herd prevalences. RESULTS: We used a Bayesian mixed effects multivariable logistic regression model to predict TB occurrence in either domestic or wild mammals per municipality in 2007 by using information from the previous year. The municipal TB distribution and endemicity was clustered in the western part of the region and clearly overlapped with the explanatory variables identified in the final model: (1) incident cattle farms, (2) number of years of veterinary inspection of big game hunting events, (3) prevalence in wild boar, (4) number of sampled cattle, (5) persistent bTB-infected cattle farms, (6) prevalence in red deer, (7) proportion of beef farms, and (8) farms devoted to bullfighting cattle. CONCLUSIONS: The combination of these eight variables in the final model highlights the importance of the persistence of the infection in the hosts, surveillance efforts and some cattle management choices in the circulation of M. bovis in the region. The spatial distribution of these variables, together with particular Mediterranean features that favour the wildlife-livestock interface may explain the M. bovis persistence in this region. Sanitary authorities should allocate efforts towards specific areas and epidemiological situations where the wildlife-livestock interface seems to critically hamper the definitive bTB eradication success.     

Coyotes as Sentinels for Monitoring Bovine Tuberculosis Prevalence in White-Tailed Deer

Abstract: Mycobacterium bovis, the causative agent of bovine tuberculosis (bTB), is endemic in free-ranging white-tailed deer (Odocoileus virginianus) in 5 counties (Alcona, Alpena, Montmorency, Oscoda, and Presque Isle) in the northeastern Lower Peninsula of Michigan, USA. The presence of a wildlife reservoir of tuberculosis in Michigan and the incidence of bTB in cattle (Bos taurus) resulted in Michigan losing its bTB accredited-free status. Subsequent wildlife surveillance programs identified relatively high disease prevalence in coyotes (Canis latrans), generating interest in their potential to serve as a sentinel species to detect bTB prevalence in white-tailed deer. Our goal was to develop an empirical basis for generating hypotheses about the spatial epidemiology of bTB infection in coyotes for future surveillance, management, and modeling efforts. Though variation in coyote home-range size may confound attempts to spatially correlate the incidence of disease in the sentinel and host species at a fine scale, overlap zones (OZs) between adjacent coyote home ranges may be the appropriate sample unit for spatially correlating disease prevalence in coyotes and white-tailed deer. Because overlapping home ranges are generally configured around resource rich (e.g., small mammals and white-tailed deer) timber management patches, the OZ concentrates spatial interaction between adjacent groups in a relatively small area. Furthermore, there is a direct relationship between interaction probabilities and the spatial dispersion of those patches. The latter finding provides a useful metric to incorporate into future efforts to develop spatially explicit models of bTB dynamics. Modeling efforts can then be used as a foundation to predict the epidemiological ramifications of alterations in intensively managed forested landscapes. (JOURNAL OF WILDLIFE MANAGEMENT 71(5):1545-1554; 2007)     

An outbreak of a hemorrhagic disease in white-tailed deer in Kentucky.

In 1971, an outbreak of a hemorrhagic disease occurred in captive and free-ranging white-tailed deer (Odocoileus virginianus) in Mammoth Cave National Park, Kentucky, Clinical signs and gross pathological lesions were consistent with those of epizootic hemorrhagic disease and bluetongue, as were serological and histopathological findings for samples sent to other laboratories. The infection rate among the 104 captive deer was 88-92%, and that among the free-ranging Park deer appeared to be similar. Mortality was negligible in the Park deer, but 65 (62%) of the captive deer died. The deaths were bimodally distributed over a 36-day period, and the mortality rate decreased from 97-100% for deer clinically ill during the first 17 days of the outbreak to 58% for deer first exhibiting clinical signs on day 16 or later. Mortality was equal in males and females, but less in yearlings than among fawns or adults. Winter mortality among survivors of the initial outbreak was associated with low ambient temperatures and sometimes fungal and bacterial abscesses, possibly sequelae or complications of the hemorrhagic disease. The pregnancy and birth rates among surviving does appeared to be normal.     

Xylazine and ketamine-induced glycosuria in white-tailed deer

This study documents glycosuria effects of xylazine and ketamine in eight captive and 19 free-ranging white-tailed deer (Odocoileus virginianus) from January to April 1985. Mean urinary glucose:creatinine ratios in two groups of deer fed high protein-high energy and low protein-low energy diets and in free-ranging deer were 1,000, 719, and 259, respectively. Glucose did not occur in urine of deer immobilized by physical restraint. Glucose:creatinine increased with the time interval between xylazine injection and urine collection in the two groups of captive deer.     

Prevalence of Escherichia coli O157:H7 in white-tailed deer from Louisiana

Escherichia coli O157:H7 (EC O157) is an important zoonosis. White-tailed deer (Odocoileus virginianus) have been implicated in transmission of this bacterium to humans and have been suggested as reservoirs that might affect carriage in cattle populations. Our study objectives were to estimate prevalence of EC O157 in feces of hunter-harvested deer and to describe fecal shedding patterns in a captive herd sampled over 1 yr. Prevalence of EC O157 in hunter-harvested deer was 0.3% (n = 338). In August 2001, EC O157 was detected in one of 55 deer (1.8%) from the captive herd. Prevalence over the 1-yr period was 0.4% (n = 226). Escherichia coli O157:H7 was rarely isolated from hunter-harvested deer during the winter. We could not describe a seasonal shedding pattern based on one positive sample in the captive herd. These data do not support a prominent role of deer as a reservoir for EC O157 for cattle or humans.     

Comparing life expectancy of three deer species between captive and wild populations

Life in zoological gardens provides a number of benefits to captive animals, resulting in an artificial reduction of the “struggle for life” compared to their free-ranging counterparts. These advantages should result in a higher chance of surviving from 1 year to the next, and thus in longer average life expectancies for captive animals, given that the biological requirements of the species are adequately met. Here, we compare the life expectancy of captive and free-ranging populations of three deer species (reindeer Rangifer tarandus, red deer Cervus elaphus, and roe deer Capreolus capreolus). Whereas captive reindeer and red deer had life expectancies equal to or longer than free-ranging individuals, the life expectancy of captive roe deer was shorter than that of free-ranging animals. These results support the impression that roe deer are difficult to keep in zoos, whereas reindeer and red deer perform well under human care. We suggest that the mean life expectancy of captive populations relative to that of corresponding free-ranging populations is a reliable indicator to evaluate the husbandry success of a species in captivity.     

Review of the 2012 Epizootic Hemorrhagic Disease Outbreak in Domestic Ruminants in the United States

An unusually large number of cases of Epizootic hemorrhagic disease (EHD) were observed in United States cattle and white-tailed deer in the summer and fall of 2012. USDA APHIS Veterinary Services area offices were asked to report on foreign animal disease investigations and state diagnostic laboratory submissions which resulted in a diagnosis of EHD based on positive PCR results. EHD was reported in the following species: cattle (129 herds), captive white-tailed deer (65 herds), bison (8 herds), yak (6 herds), elk (1 herd), and sheep (1 flock). A majority of the cases in cattle and bison were found in Nebraska, South Dakota, and Iowa. The majority of cases in captive white-tailed deer were found in Ohio, Iowa, Michigan, and Missouri. The most common clinical sign observed in the cattle and bison herds was oral lesions. The major observation in captive white-tailed deer herds was death. Average within-herd morbidity was 7% in cattle and bison herds, and 46% in captive white-tailed deer herds. The average within-herd mortality in captive white-tailed deer herds was 42%.     

Nitric oxide production as an indication of Mycobacterium bovis infection in white-tailed deer (Odocoileus virginianus)

White-tailed deer (Odocoileus virginianus) are reservoirs for Mycobacterium bovis in northeast Michigan, USA. Production of nitric oxide (NO) by activated macrophages is a potent mechanism of mycobacterial killing. The capacity of macrophages to produce NO, however, varies among mammalian species. The objective of this study was to determine if mononuclear cells from white-tailed deer produce nitrite as an indication of NO production and, if so, is NO produced in response to stimulation with M. bovis antigens. Supernatants were harvested from adherent peripheral blood mononuclear cell (PBMC) cultures that had been stimulated with either Mannheimia haemolytica lipopolysaccharide (LPS) or media alone (i.e., no stimulation). Nitrite levels within M. haemolytica LPS-stimulated culture supernatants exceeded (P < 0.05) those detected within supernatants from non-stimulated cultures as well as those detected within supernatants from cultures receiving an inhibitor of NO synthase in addition to M. haemolytica LPS. In response to stimulation with M. bovis antigens, nitrite production by PBMC from M. bovis-infected deer exceeded (P < 0.05) the production by PBMC from non-infected deer. The response of PBMC from infected deer to M. bovis antigens exceeded (P < 0.05) the response of parallel cultures from the same deer receiving no stimulation. The response of PBMC from M. bovis-infected deer to M. avium antigens did not differ from that of PBMC from M. bovis-infected deer to no stimulation or from that of PBMC from non-infected deer to M. avium antigens. These findings indicate that adherent PBMC from white-tailed deer are capable of NO production and that mononuclear cells isolated from M. bovis-infected white-tailed deer produce NO in an antigen-specific recall response.     

Immune responses of white-tailed deer (Odocoileus virginianus) to Mycobacterium bovis BCG vaccination

The objective was to evaluate cellular immune response of captive white-tailed deer (Odocoileus virginianus) to live Mycobacterium bovis bacille Calmette Guerin (BCG) vaccination and to determine diagnostic implications of these responses. In vitro proliferative and interferon-gamma (IFN-gamma) responses to M. bovis purified protein derivative (PPD) were detected beginning 9 days postvaccination. Responses to Mycobacterium avium PPD, however, generally exceeded responses to M. bovis PPD. Interferon-gamma responses to M. avium PPD were not detected prior to vaccination nor in nonvaccinated deer, suggesting that vaccination with BCG boosted prior quiescent M. avium-sensitized cells. Both CD4+ and gammadelta T cells from vaccinated deer proliferated in response to M. bovis PPD stimulation. Intradermal administration of M. bovis PPD resulted in increases in skin thickness of vaccinated deer beginning 24 hr postinjection. Such early reactions were characterized by edema and minimal mononuclear cell infiltration, whereas later reactions (i.e., 72 hr postinjection) were more typical of delayed type hypersensitivity. Upon in vitro activation with pokeweed mitogen, CD44 expression increased and CD62L expression decreased on lymphocytes from deer regardless of vaccination status. Likewise, M. bovis PPD stimulation of lymphocytes from vaccinated deer resulted in increases in CD44 expression and decreases in CD62L expression. These findings demonstrate the potential of BCG vaccination to elicit strong cell-mediated immune responses and appropriate alterations in CD44 and CD62L expression with in vitro stimulation of white-tailed deer lymphocytes. In relation to M. bovis diagnosis, vaccination of white-tailed deer with BCG can induce skin test responses that classify the animal as a tuberculosis reactor. In contrast, BCG vaccination will likely not interfere with tuberculosis testing by the IFN-gamma assay.     

Serodiagnosis of Tuberculosis in Asian Elephants (Elephas maximus) in Southern India: A Latent Class Analysis

Background

Mycobacterium tuberculosis, a causative agent of chronic tuberculosis disease, is widespread among some animal species too. There is paucity of information on the distribution, prevalence and true disease status of tuberculosis in Asian elephants (Elephas maximus). The aim of this study was to estimate the sensitivity and specificity of serological tests to diagnose M. tuberculosis infection in captive elephants in southern India while simultaneously estimating sero-prevalence.

Methodology/Principal Findings

Health assessment of 600 elephants was carried out and their sera screened with a commercially available rapid serum test. Trunk wash culture of select rapid serum test positive animals yielded no animal positive for M. tuberculosis isolation. Under Indian field conditions where the true disease status is unknown, we used a latent class model to estimate the diagnostic characteristics of an existing (rapid serum test) and new (four in-house ELISA) tests. One hundred and seventy nine sera were randomly selected for screening in the five tests. Diagnostic sensitivities of the four ELISAs were 91.3–97.6% (95% Credible Interval (CI): 74.8–99.9) and diagnostic specificity were 89.6–98.5% (95% CI: 79.4–99.9) based on the model we assumed. We estimate that 53.6% (95% CI: 44.6–62.8) of the samples tested were free from infection with M. tuberculosis and 15.9% (97.5% CI: 9.8 - to 24.0) tested positive on all five tests.

Conclusions/Significance

Our results provide evidence for high prevalence of asymptomatic M. tuberculosis infection in Asian elephants in a captive Indian setting. Further validation of these tests would be important in formulating area-specific effective surveillance and control measures.