Development and evaluation of a gamma-interferon assay for tuberculosis in badgers (Meles meles)

Dalley, Deanna; Davé, Dipesh; Lesellier, Sandrine; Palmer, Si; Crawshaw, T. R.; Hewinson, R. Glyn; Chambers, Mark A.

doi:10.1016/j.tube.2007.11.001

Cited by 70 publications

(93 citation statements)

References 36 publications

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“…Thus, the BrockTB Stat-Pak had a sensitivity for detection of TB of 49.2% (95% confidence interval [CI] ϭ 44.1 to 54.4%) and a specificity of 93.1% (95% CI ϭ 91.4 to 94.6%). These figures are within the ranges previously reported by us with a smaller sample size (13) and are equivalent to the performance of the existing serum enzyme-linked immunosorbent assay-based test for TB (Brock Test) (2,5,12). Although the specificity was relatively high, this is likely to be an underestimate.…”

supporting

confidence: 85%

Validation of the BrockTB Stat-Pak Assay for Detection of Tuberculosis in Eurasian Badgers ( Meles meles ) and Influence of Disease Severity on Diagnostic Accuracy

Chambers¹,

Crawshaw²,

Waterhouse³

et al. 2008

J Clin Microbiol

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A lateral-flow immunoassay (BrockTB Stat-Pak) for detecting tuberculosis in Eurasian badgers was 49% sensitive and 93% specific against culture for M. bovis (n ‫؍‬ 1,464) at necropsy. However, the sensitivity was significantly higher (66 to 78%) in animals with more severe tuberculosis, indicating that the BrockTB Stat-Pak may be useful for the detection of badgers with the greatest risk of transmitting disease.Despite attempts to control bovine tuberculosis (TB), the average incidence of disease in cattle in Great Britain increased an estimated 225% between the years 1996 and 2006 (7), causing considerable economic loss to the government and the farming community. In parts of Great Britain and Ireland, Eurasian badger (Meles meles) populations constitute a reservoir of infection with Mycobacterium bovis and a potential source of infection to cattle (8,14,15). In an effort to simplify the serodetection of badger TB, we developed a lateral-flow immunoassay (13) that is now manufactured as the BrockTB Stat-Pak assay (Chembio Diagnostic Systems, Inc., Medford, NY). We report here the results of ongoing evaluation of the assay, in particular the influence of disease severity on diagnostic accuracy.Badger sera were obtained in Great Britain from two sources and stored frozen at Ϫ20°C until testing (i) 1,464 animals killed as part of the defra/Independent Scientific Group Randomized Badger Culling Trial (RBCT) (8) and (ii) 68 animals captured, sampled, and then released as part of an ongoing ecological and epidemiological study in Woodchester Park (WP), southwest England (6). Each badger from the RBCT was subjected to routine necropsy examination and culture for the presence of M. bovis. Carcasses were stored at 4°C and examined by a standardized necropsy protocol within 3 days of submission. A range of tissues and lymph nodes were examined for evidence of TB. In badgers with no lesions the bronchial, mediastinal, and retropharyngeal lymph nodes were placed in 1% cetyl-pyridinium chloride prior to bacterial culture. In badgers with lesions the lesion tissue was always submitted for culture. Bite wounds were sampled separately. Tissues were processed within 72 h of sampling. The cetyl-pyridinium chloride was discarded, and the tissues were rinsed in saline and then emulsified before inoculation onto six slopes of modified Middlebrook 7H11 agar. The slopes were incubated at 37 Ϯ 2°C. Any growth of organisms characteristic of mycobacteria was identified by spoligotyping (9). The infection status of WP badgers was determined by bacterial culture of clinical samples of feces, urine, sputum, pus from abscesses, and bite wound swabs as described previously (3).Compared to the culture results from tissues taken at necropsy (n ϭ 1,464), the findings were as follows: BrockTB StatPak positive, culture negative, n ϭ 74; BrockTB Stat-Pak negative, culture negative, n ϭ 1,004; BrockTB Stat-Pak positive, culture positive, n ϭ 190; and BrockTB Stat-Pak negative, culture positive, n ϭ 196. Thus, the BrockTB Stat-Pak had a sensitivity ...

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supporting

confidence: 85%

Validation of the BrockTB Stat-Pak Assay for Detection of Tuberculosis in Eurasian Badgers ( Meles meles ) and Influence of Disease Severity on Diagnostic Accuracy

Chambers¹,

Crawshaw²,

Waterhouse³

et al. 2008

J Clin Microbiol

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“…Drewe 2007, personal observation), it is possible that other meerkats may alter their behaviour towards infected individuals, perhaps targeting them with more (or less) aggression or grooming. The application of other tests that may detect early stages of infection, such as the gamma interferon test (Dalley et al 2008), would be one possible solution. Logistical limitations such as the remoteness of the study site precluded the use of this test in the meerkat population.…”

Section: Discussionmentioning

confidence: 99%

Who infects whom? Social networks and tuberculosis transmission in wild meerkats

2009

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Transmission of infectious diseases is strongly influenced by who contacts whom. Despite the global distribution of tuberculosis (TB) in free-living wild mammal populations, little is known of the mechanisms of social transmission of Mycobacterium bovis between individuals. Here, I use a network approach to examine for correlations between five distinct types of intra-and intergroup social interaction and changes in TB status of 110 wild meerkats (Suricata suricatta) in five social groups over two years. Contrary to predictions, the most socially interactive animals were not at highest risk of acquiring infection, indicating that in addition to contact frequency, the type and direction of interactions must be considered when quantifying disease risk. Within social groups, meerkats that groomed others most were more likely to become infected than individuals who received high levels of grooming. Conversely, receiving, but not initiating, aggression was associated with M. bovis infection. Incidence of intergroup roving by male meerkats was correlated with the rovers themselves subsequently testing TB-positive, suggesting a possible route for transmission of infection between social groups. Exposure time was less important than these social interactions in influencing TB risk. This study represents a novel application of social network analysis using empirical data to elucidate the role of specific interactions in the transmission of an infectious disease in a free-living wild animal population.

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“…Currently, infections in live badgers can be monitored through trapping and diagnosis with immunoassays (gamma interferon [IFN-␥] assay [18] and the Brock Stat-Pak assay [7]) and culture (19). Culture of clinical samples (sputum and feces) has low sensitivity of 8% and specificity of 100% (20).…”

mentioning

confidence: 99%

Performance of a Noninvasive Test for Detecting Mycobacterium bovis Shedding in European Badger (Meles meles) Populations

et al. 2015

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eThe incidence of Mycobacterium bovis, the causative agent of bovine tuberculosis, in cattle herds in the United Kingdom is increasing, resulting in substantial economic losses. The European badger (Meles meles) is implicated as a wildlife reservoir and is the subject of control measures aimed at reducing the incidence of infection in cattle populations. Understanding the epidemiology of M. bovis in badger populations is essential for directing control interventions and understanding disease spread; however, accurate diagnosis in live animals is challenging and currently uses invasive methods. Here we present a noninvasive diagnostic procedure and sampling regimen using field sampling of latrines and detection of M. bovis with quantitative PCR tests, the results of which strongly correlate with the results of immunoassays in the field at the social group level. This method allows M. bovis infections in badger populations to be monitored without trapping and provides additional information on the quantities of bacterial DNA shed. Therefore, our approach may provide valuable insights into the epidemiology of bovine tuberculosis in badger populations and inform disease control interventions.M ycobacterium bovis infection in wildlife is an issue of growing importance worldwide, with infections found in a range of species, including buffalo in Africa (1), wild boar in Spain (2), brushtail possums in New Zealand (3), and European badgers in the United Kingdom (4) and the Republic of Ireland (5). In the United Kingdom and the Republic of Ireland, badgers are involved in the transmission of tuberculosis (TB) to cattle (6-8). The incidence of M. bovis in cattle herds in the United Kingdom has been increasing for over 30 years (9), resulting in substantial economic losses (10). Once infected, badgers may intermittently shed M. bovis cells in sputum, feces, and urine (4), creating an environmental source of potential infection for other badgers and cattle (11,12). M. bovis DNA has been shown to survive outside the host for up to 21 months, and 16S rRNA has been detected in badger setts and latrines (13). In addition, studies have found a 2.5% positivity rate when culturing from badger feces (14), and M. bovis has been cultured from cattle feces several months after excretion (15). Furthermore, M. bovis that had persisted in soil for over 12 months was able to colonize mice (16). This indicates that at least a proportion of M. bovis cells shed in badger feces can remain viable in the environment. Monitoring M. bovis infections in badger populations is important for understanding the location and spread of disease and directing control efforts. TB control interventions targeted at badgers are currently based on culling, vaccination, and farm biosecurity (17).Accurate diagnosis of M. bovis infections in live animals is challenging yet essential in order to understand the epidemiology of the disease and its onward spread. Currently, infections in live badgers can be monitored through trapping and diagnosis with immunoassays (g...

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Development and evaluation of a gamma-interferon assay for tuberculosis in badgers (Meles meles)

Cited by 70 publications

References 36 publications

Validation of the BrockTB Stat-Pak Assay for Detection of Tuberculosis in Eurasian Badgers ( Meles meles ) and Influence of Disease Severity on Diagnostic Accuracy

Validation of the BrockTB Stat-Pak Assay for Detection of Tuberculosis in Eurasian Badgers ( Meles meles ) and Influence of Disease Severity on Diagnostic Accuracy

Who infects whom? Social networks and tuberculosis transmission in wild meerkats

Performance of a Noninvasive Test for Detecting Mycobacterium bovis Shedding in European Badger (Meles meles) Populations

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