Epidemiology of Mycobacterium bovis infection in free-ranging rhinoceros in Kruger National Park, South Africa.

Mycobacterium bovis infection, which is a prominent cause of bovine tuberculosis, has been confirmed by mycobacterial culture in African rhinoceros species in Kruger National Park (KNP), South Africa. In this population-based study of the epidemiology of M. bovis in 437 African rhinoceros (Diceros bicornis, Ceratotherium simum), we report an estimated prevalence of 15.4% (95% CI: 10.4 to 21.0%), based on results from mycobacterial culture and an antigen-specific interferon gamma release assay from animals sampled between 2016 and 2020. A significant spatial cluster of cases was detected near the southwestern park border, although infection was widely distributed. Multivariable logistic regression models, including demographic and spatiotemporal variables, showed a significant, increasing probability of M. bovis infection in white rhinoceros based on increased numbers of African buffalo (Syncerus caffer) herds in the vicinity of the rhinoceros sampling location. Since African buffaloes are important maintenance hosts for M. bovis in KNP, spillover of infection from these hosts to white rhinoceros sharing the environment is suspected. There was also a significantly higher proportion of M. bovis infection in black rhinoceros in the early years of the study (2016­2018) than in 2019 and 2020, which coincided with periods of intense drought, although other temporal factors could be implicated. Species of rhinoceros, age, and sex were not identified as risk factors for M. bovis infection. These study findings provide a foundation for further epidemiological investigation of M. bovis, a multihost pathogen, in a complex ecosystem that includes susceptible species that are threatened and endangered.

Extensive differential DNA methylation between tuberculosis skin test positive and skin test negative cattle.

Bovine tuberculosis (bTB), caused by Mycobacterium bovis (M. bovis), represents a significant problem for the agriculture industry as well as posing a risk for human health. Current diagnostic tests for bTB target the cell-mediated immune (CMI) response to infection with M. bovis, primarily through screening of animals with the tuberculin skin test. Epigenetic modifications have been shown to alter the course of the immune response and differentially methylated regions (DMRs) might also influence the outcome of the skin test in cattle. Whole Genome Bisulphite Sequencing (WGBS) was used to profile DNA methylation levels from peripheral blood of a group of cattle identified as test positive for M. bovis (positive for the single intradermal comparative tuberculin test (SICTT) and/or the interferon-γ release assay compared to a test negative control group [n = 8/group, total of 16 WGBS libraries]. Although global methylation profiles were similar for both groups across the genome, 223 DMRs and 159 Differentially Promoter Methylated Genes (DPMGs) were identified between groups with an excess of hypermethylated sites in SICTT positive cattle (threshold > 15% differential methylation). Genes located within these DMRs included the Interleukin 1 receptor (IL1R1) and MHC related genes (BOLA and BOLA-DQB). KEGG pathway analysis identified enrichment of genes involved in Calcium and MAPK signalling, as well as metabolism pathways. Analysis of DMRs in a subset of SICTT negative cattle that were IFN-γ positive showed differential methylation of genes including Interleukin 10 Receptor, alpha (IL10RA), Interleukin 17 F (IL17F) and host defence peptides (DEFB and BDEF109). This study has identified a number of immune gene loci at which differential methylation is associated with SICTT test results and the degree of methylation could influence effective host immune responses.

A scoping review on bovine tuberculosis highlights the need for novel data streams and analytical approaches to curb zoonotic diseases.

Zoonotic diseases represent a significant societal challenge in terms of their health and economic impacts. One Health approaches to managing zoonotic diseases are becoming more prevalent, but require novel thinking, tools and cross-disciplinary collaboration. Bovine tuberculosis (bTB) is one example of a costly One Health challenge with a complex epidemiology involving humans, domestic animals, wildlife and environmental factors, which require sophisticated collaborative approaches. We undertook a scoping review of multi-host bTB epidemiology to identify trends in species publication focus, methodologies, and One Health approaches. We aimed to identify knowledge gaps where novel research could provide insights to inform control policy, for bTB and other zoonoses. The review included 532 articles. We found different levels of research attention across episystems, with a significant proportion of the literature focusing on the badger-cattle-TB episystem, with far less attention given to tropical multi-host episystems. We found a limited number of studies focusing on management solutions and their efficacy, with very few studies looking at modelling exit strategies. Only a small number of studies looked at the effect of human disturbances on the spread of bTB involving wildlife hosts. Most of the studies we reviewed focused on the effect of badger vaccination and culling on bTB dynamics with few looking at how roads, human perturbations and habitat change may affect wildlife movement and disease spread. Finally, we observed a lack of studies considering the effect of weather variables on bTB spread, which is particularly relevant when studying zoonoses under climate change scenarios. Significant technological and methodological advances have been applied to bTB episystems, providing explicit insights into its spread and maintenance across populations. We identified a prominent bias towards certain species and locations. Generating more high-quality empirical data on wildlife host distribution and abundance, high-resolution individual behaviours and greater use of mathematical models and simulations are key areas for future research. Integrating data sources across disciplines, and a "virtuous cycle" of well-designed empirical data collection linked with mathematical and simulation modelling could provide additional gains for policy-makers and managers, enabling optimised bTB management with broader insights for other zoonoses.

Disseminated, fatal reactivation of bovine tuberculosis in a patient treated with adalimumab: a case report and review of the literature.

PURPOSE: Tumor necrosis factor inhibitors (TNFi) are known to increase the risk of tuberculosis (TB) reactivation, though cases involving Mycobacterium bovis are rarely reported. CASE PRESENTATION/RESULTS: We describe a case of disseminated TB with M. bovis in a 78-year-old woman with a negative Interferon-Gamma-Release Assay (IGRA), taking adalimumab due to rheumatoid polyarthritis, which resulted in a fatal outcome. The atypical clinical and histopathological features were initially interpreted as sarcoidosis. The case occurred in Switzerland, an officially bovine tuberculosis-free country. The whole genome sequence of the patient's cultured M. bovis isolate was identified as belonging to the animal lineage La1.2, the main genotype in continental Europe, but showed significant genetic distance from previously sequenced Swiss cattle strains. In a literature review, four cases of bovine tuberculosis reactivation under TNFi treatment were identified, with pulmonal, oral and intestinal manifestations. Similar to our patient, two cases presented a negative IGRA before TNFi initiation, which later converted to positive upon symptomatic presentation of M. bovis infection. CONCLUSION: This case highlights the diagnostic challenges of TB in immunosuppressed patients, the limited sensitivity of IGRA, and the importance of considering TB reactivation even in regions declared free of bovine tuberculosis. Detailed patient histories, including potential exposure to unpasteurized dairy products, are essential for guiding preventive TB treatment before TNFi initiation.

Bacteriological culture and direct PCR for detecting the Mycobacterium tuberculosis complex in the Italian eradication campaign: a decade of experience at the National Reference Laboratory.

AIMS: Our study evaluates the capacity of direct real-time PCR for detecting Mycobacterium tuberculosis complex (MTBC), with a focus on diagnostic performances and the feasibility of implementing this protocol in an eradication campaign. Specifically, we compare the effectiveness of the direct PCR method to various culture systems used by the Italian National Reference Laboratory over the last decade to detect MTBC. METHODS AND RESULTS: Bovine tissue samples were routinely tested and analyzed for bovine tuberculosis (bTB) confirmation using microbiological culture (solid and liquid media), histopathological analysis, and a direct PCR assay targeting IS6110, an insertion sequence specific to the MTBC that is widely used for tuberculosis diagnosis. The direct real-time PCR demonstrated a high concordance (K = 0.871) with microbiological culture, as well as good sensitivity (91.84%) and specificity (95.24%). In contrast, histopathology demonstrated lower concordance (K = 0.746) and performance levels (sensitivity 91.41%, specificity 82.88%). Liquid media promoted faster and more efficient growth of MTBC than solid media. M. bovis and M. caprae had the comparable ability to respond to the direct real-time PCR test and grow on the microbiological medium. CONCLUSIONS: This study confirms that direct real-time PCR can detect MTBC with high diagnostic accuracy within a few days. This study found no significant differences in performance between culture media and direct PCR for M. bovis and M. caprae.

Comparative analysis of tuberculin and defined antigen skin tests for detection of bovine tuberculosis in buffaloes (Bubalus bubalis) in Haryana state, India.

BACKGROUND: Bovine tuberculosis (bTB) is a chronic disease that results from infection with any member of the Mycobacterium tuberculosis complex. Infected animals are typically diagnosed with tuberculin-based intradermal skin tests according to World Organization of Animal Health which are presently in use. However, tuberculin is not suitable for use in BCG-vaccinated animals due to a high rate of false-positive reactions. Peptide-based defined skin test (DST) antigens have been identified using antigens (ESAT-6, CFP-10 and Rv3615c) which are absent from BCG, but their performance in buffaloes remains unknown. To assess the comparative performance of DST with the tuberculin-based single intradermal test (SIT) and the single intradermal comparative cervical test (SICCT), we screened 543 female buffaloes from 49 organized dairy farms in two districts of Haryana state in India. RESULTS: We found that 37 (7%), 4 (1%) and 18 (3%) buffaloes were reactors with the SIT, SICCT and DST tests, respectively. Of the 37 SIT reactors, four were positive with SICCT and 12 were positive with the DST. The results show that none of the animals tested positive with all three tests, and 6 DST positive animals were SIT negative. Together, a total of 43 animals were reactors with SIT, DST, or both, and the two assays showed moderate agreement (Cohen's Kappa 0.41; 95% Confidence Interval (CI): 0.23, 0.59). In contrast, only slight agreement (Cohen's Kappa 0.18; 95% CI: 0.02, 0.34) was observed between SIT and SICCT. Using a Bayesian latent class model, we estimated test specificities of 96.5% (95% CI, 92-99%), 99.7% (95% CI: 98-100%) and 99.0% (95% CI: 97-100%) for SIT, SICCT and DST, respectively, but considerably lower sensitivities of 58% (95% CI: 35-87%), 9% (95% CI: 3-21%), and 34% (95% CI: 18-55%) albeit with broad and overlapping credible intervals. CONCLUSION: Taken together, our investigation suggests that DST has a test specificity comparable with SICCT, and sensitivity intermediate between SIT and SICCT for the identification of buffaloes suspected of tuberculosis. Our study highlights an urgent need for future well-powered trials with detailed necropsy, with immunological and microbiological profiling of reactor and non-reactor animals to better define the underlying factors for the large observed discrepancies in assay performance, particularly between SIT and SICCT.

Molecular Characterisation of Mycobacterium bovis Isolates from Cattle Slaughtered in Adamawa and Gombe States, North-Eastern Nigeria.

Bovine tuberculosis is endemic in Nigeria with control measures as provided by the laws of the country being minimally enforced mostly at the abattoirs only. This study focused on bovine tuberculosis in Adamawa and Gombe States. Tuberculosis lesions were observed in 183 of 13,688 slaughtered cattle in the regions between June and December 2020. Analysis of tissue samples resulted in 17 Mycobacterium bovis isolates, predominantly from Gombe State. Spoligotyping identified four spoligotypes, including SB0944, SB1025, SB1104, and one novel pattern. MIRU-VNTR analysis further differentiated these spoligotypes into eight profiles. All isolates belonged to the Af1 clonal complex. The study emphasises the need for broader coverage and more isolates to comprehensively understand the molecular epidemiology of bovine tuberculosis in Nigeria. To enhance research and surveillance, a cost-effective approach is proposed, utilising a discriminatory VNTR panel comprising five or nine loci. The five-locus panel consists of ETR-C, QUB26, QUB11b, MIRU04, and QUB323. Alternatively, the nine-locus panel includes ETR-A, ETR-B, QUB11a, and MIRU26. Implementing this approach would provide valuable insights into the genetic diversity of M. bovis strains in Nigeria. These findings are crucial for developing effective control measures and minimising the impact of bovine tuberculosis on both animal and human health.

Putative volatile biomarkers of bovine tuberculosis infection in breath, skin and feces of cattle.

Bovine tuberculosis (bTB) is an infectious disease with significant impact on animal health, public health and international trade. Standard bTB screening in live cattle consists in injecting tuberculin and measuring the swelling at the place of injection few days later. This procedure is expensive, time-consuming, logistically challenging, and is not conclusive before performing confirmatory tests and additional analysis. The analysis of the volatile organic compounds (VOCs) emitted by non-invasive biological samples can provide an alternative diagnostic approach suitable for bTB screening. In the present study, we analyzed VOC samples emitted through the breath, feces and skin of 18 cows diagnosed with bTB from three farms from Romania, as well as of 27 negative cows for bTB from the same farms. Analytical studies employing gas chromatography coupled to mass spectrometry revealed 80 VOCs emitted through the breath, 200 VOCs released by feces, and 80 VOCs emitted through the skin. Statistical analysis of these compounds allowed the identification of 3 tentative breath VOC biomarkers (acetone; 4-methyldecane; D-limonene), 9 tentative feces VOC biomarkers (toluene; [(1,1-dimethylethyl)thio]acetic acid; alpha-thujene; camphene; phenol; o-cymene; 3-(1,1-dimethylethyl)-2,2,4,4-tetramethyl-3-pentanol; 2,5-dimethylhexane-2,5-dihydroperoxide; 2,4-di-tert-butylphenol), and 3 tentative skin VOC biomarkers (ammonia; 1-methoxy-2-propanol; toluene). The possible pathway of these volatile biomarkers is discussed.

Evaluation of the performance of the IFN-γ release assay in bovine tuberculosis free herds from five European countries.

The diagnostic methods for granting and maintenance of the official tuberculosis-free (OTF) status and for intra-Community movement of cattle are the tuberculin skin tests (single or comparative) and the interferon-γ (IFN-γ) release assay (IGRA). However, until now, IGRAs have been primarily applied in infected farms in parallel to the skin test to maximize the number of infected animals detected. Therefore, an evaluation of the performance of IGRAs in OTF herds to assess whether if their specificity is equal to or higher than that of the skin tests is needed. For this, a panel of 4365 plasma samples coming from 84 OTF herds in six European regions (five countries) was assembled and analysed using two IGRA kits, the ID Screen® Ruminant IFN-g (IDvet) and the Bovigam™ TB Kit (Bovigam). Results were evaluated using different cut-offs, and the impact of herd and animal-level factors on the probability of positivity was assessed using hierarchical Bayesian multivariable logistic regression models. The percentage of reactors ranged from 1.7 to 21.0% (IDvet: S/P ≥ 35%), and 2.1-26.3% (Bovigam: ODbovis-ODPBS ≥ 0.1 and ODbovis-ODavium ≥ 0.1) depending on the region, with Bovigam disclosing more reactors in all regions. The results suggest that specificity of IGRAs can be influenced by the production type, age and region of origin of the animals. Changes in the cut-offs could lead to specificity values above 98-99% in certain OTF populations, but no single cut-off yielding a sufficiently high specificity (equal or higher than that of skin tests) in all populations was identified. Therefore, an exploratory analysis of the baseline IFN-γ reactivity in OTF populations could help to assess the usefulness of this technique when applied for the purpose of maintaining OTF status.

Are predictions of bovine tuberculosis-infected herds unbiased and precise?

Bovine tuberculosis (bTB) is prevalent among livestock and wildlife in many countries including New Zealand (NZ), a country which aims to eradicate bTB by 2055. This study evaluates predictions related to the numbers of livestock herds with bTB in NZ from 2012 to 2021 inclusive using both statistical and mechanistic (causal) modelling. Additionally, this study made predictions for the numbers of infected herds between 2022 and 2059. This study introduces a new graphical method representing the causal criteria of strength of association, such as R2, and the consistency of predictions, such as mean squared error. Mechanistic modelling predictions were, on average, more frequently (3 of 4) unbiased than statistical modelling predictions (1 of 4). Additionally, power model predictions were, on average, more frequently (3 of 4) unbiased than exponential model predictions (1 of 4). The mechanistic power model, along with annual updating, had the highest R2 and the lowest mean squared error of predictions. It also exhibited the closest approximation to unbiased predictions. Notably, significantly biased predictions were all underestimates. Based on the mechanistic power model, the biological eradication of bTB from New Zealand is predicted to occur after 2055. Disease eradication planning will benefit from annual updating of future predictions.

Assessing the impact of a test and vaccinate or remove badger intervention project on bovine tuberculosis levels in cattle herds.

Bovine tuberculosis (bTB) is a chronic, zoonotic infection of domestic and wild animals caused mainly by Mycobacterium bovis. The Test and Vaccinate or Remove (TVR) project was a 5-year intervention (2014-2018) applied to Eurasian badgers (Meles meles) in a 100 km2 area of County Down, Northern Ireland. This observational study used routine bTB surveillance data of cattle to determine if the TVR intervention had any effect in reducing the infection at a herd level. The study design included the TVR treatment area (Banbridge) compared to the three adjacent 100 km2 areas (Dromore, Ballynahinch, and Castlewellan) which did not receive any badger intervention. Results showed that there were statistically lower bTB herd incidence rate ratios in the Banbridge TVR area compared to two of the other three comparison areas, but with bTB herd history and number of bTB infected cattle being the main explanatory variables along with Year. This finding is consistent with other study results conducted as part of the TVR project that suggested that the main transmission route for bTB in the area was cattle-to-cattle spread. This potentially makes any wildlife intervention in the TVR area of less relevance to bTB levels in cattle. It must also be noted that the scientific power of the TVR study (76%) was below the recommended 80%, meaning that results must be interpreted with caution. Even though statistical significance was achieved in two cattle-related risk factors, other potential risk factors may have also demonstrated significance in a larger study.

Development and validation of a one-tube, nested real-time PCR method suitable for routine detection of Mycobacterium bovis in animal tissue.

AIMS: Development and validation of a real-time PCR test for high-throughput routine screening of animal tissue for Mycobacterium bovis and other Mycobacterium tuberculosis complex (MTBC) members. METHODS AND RESULTS: A preliminary study compared the results of a combination of five tissue preparation/DNA extraction methods and nine PCR assays on a panel of 92 cattle tissue samples of known M. bovis culture status (55 positive and 37 negative). The combination of DNA extraction and PCR was found to be important in achieving optimal detection of M. bovis. The optimal combination of a simple tissue preparation/DNA extraction method and a one-tube, nested real-time PCR to maximize the sensitivity of detection of an M. bovis-specific RD4 deletion and an IS1081 MTBC-specific target was selected for further evaluation. In total, tissue samples collected from 981 cattle and 366 non-bovine animals and submitted for routine TB culture were parallel tested with the selected method, as well as tissue samples obtained from 156 animals in certified TB-free cattle herds. CONCLUSION: For cattle, the optimized RD4-IS1081 PCR test exhibited a diagnostic sensitivity of 96% (95% CI: 94-97%) and specificity of 97% (95% CI: 95-98%) compared to culture. Specificity was 100% when testing the 156 samples from known TB-free cattle. For non-bovine species, the PCR had a diagnostic sensitivity of 93% (95% CI: 83-98%) and a specificity of 99% (95% CI: 97-100%).

Challenges and opportunities of sharing animal health data for research and disease management: a case study of bovine tuberculosis.

The sharing of animal disease data should be encouraged. The analysis of such data will broaden our knowledge of animal diseases and potentially provide insights into their management. However, the need to conform to data protection rules in the sharing of such data for analysis purposes often poses practical difficulties. This paper sets out the challenges and the methods used for the sharing of animal health data in England, Scotland and Wales - Great Britain - using bovine tuberculosis (bTB) data as a case study. The data sharing described is undertaken by the Animal and Plant Health Agency on behalf of the Department for Environment, Food and Rural Affairs and the Welsh and Scottish Governments. It should be noted that animal health data are held at the level of Great Britain (rather than the United Kingdom - which includes Northern Ireland), as Northern Ireland's Department of Agriculture, Environment and Rural Affairs has its own separate data systems. Bovine tuberculosis is the most significant and costly animal health problem facing cattle farmers in England and Wales. It can be devastating for farmers and farming communities and the control costs for taxpayers in Great Britain are over £150 million a year. The authors describe two methods of data sharing - first, where data are requested by, and delivered to, an academic institution for epidemiological or scientific analysis, and second, where data are proactively published in an accessible and meaningful way. They provide details of an example of the second method, namely, the free-to-access website â€Ëœinformation bovine TB' (https://ibtb.co.uk), which publishes bTB data for the benefit of the farming community and veterinary health professionals.

L'échange et le partage de données sur les maladies animales sont des pratiques à encourager. En effet, l'analyse de ces données permet d'étoffer les connaissances sur les maladies animales et peut aussi apporter un nouvel éclairage sur leur gestion. Néanmoins, la nécessité de se conformer aux règles sur la protection des données pose souvent des difficultés pratiques lors des échanges de ce type de données à des fins d'analyse. Les auteurs expliquent les difficultés rencontrées en matière d'échange de données de santé animale en Angleterre, en écosse et au Pays de Galles (Grande-Bretagne), ainsi que les méthodes utilisées, à partir de l'exemple concret des données relatives à la tuberculose bovine. L'échange et le partage de données sont réalisés par l'Agence britannique de santé animale et végétale, pour le compte du ministère britannique de l'Environnement, de l'Alimentation et des Affaires rurales et des gouvernements gallois et écossais. Il convient de préciser que les données de santé animale dont il s'agit sont celles conservées au niveau de la Grande-Bretagne seulement (et non du Royaume-Uni, qui inclut l'Irlande du Nord), étant donné que le ministère de l'Agriculture, de l'Environnement et des Affaires rurales de l'Irlande du Nord possède ses propres systèmes de données. La tuberculose bovine est le principal problème de santé animale auquel sont confrontés les éleveurs de bovins en Angleterre et au Pays de Galles, et le plus coûteux à traiter. La survenue de la tuberculose bovine est une catastrophe pour les éleveurs affectés et leur communauté. En outre, le coût annuel de son contrôle s'élève à plus de 150 millions de livres pour le contribuable britannique. Les auteurs décrivent deux méthodes d'échange et de partage de données : la première est celle où une institution de recherche demande et obtient l'accès à des données particulières afin de réaliser une étude épidémiologique ou scientifique ; la deuxième consiste à publier les données de manière proactive et constructive, en les rendant facilement accessibles. Un exemple concret de cette deuxième méthode est décrit en détail : il s'agit du site web d'information sur la tuberculose bovine (https://ibtb.co.uk), d'accès libre, qui diffuse des informations sur cette maladie à l'intention des éleveurs et des professionnels de la santé animale.

Convendría alentar la puesta en común de datos zoosanitarios, pues el análisis de estos datos nos ayudará a conocer más y mejor las enfermedades animales y, a la postre, puede darnos pistas sobre la mejor manera de afrontarlas. Ocurre a menudo, sin embargo, que el prescriptivo cumplimiento de las reglas de protección de datos plantee dificultades prácticas para poner estos datos en común con fines de análisis. Los autores, empleando como ejemplo un estudio sobre la tuberculosis bovina, describen esas dificultades y los métodos utilizados para compartir datos zoosanitarios en Inglaterra, Escocia y Gales (Gran Bretaña). En el ejemplo descrito, la Agencia de Sanidad Animal y Vegetal del Reino Unido fue la instancia que impulsó la puesta en común de los datos en nombre del Departamento de Medio Ambiente, Alimentación y Asuntos Rurales del Reino Unido y de los gobiernos galés y escocés. Conviene puntualizar que los datos zoosanitarios cubren el territorio de Gran Bretaña (y no de todo el Reino Unido, que incluye Irlanda del Norte), ya que el Departamento de Medio Ambiente, Alimentación y Asuntos Rurales norirlandés dispone de su propio sistema de datos independiente. La tuberculosis bovina es el problema zoosanitario más importante y oneroso al que hacen frente las explotaciones de vacuno en Inglaterra y Gales. Esta enfermedad no solo puede ser devastadora para los productores y profesionales del sector, sino que la lucha contra ella cuesta al contribuyente británico más de 150 millones de libras al año. Los autores describen dos métodos para compartir de datos: en el primero de ellos, un establecimiento universitario solicita y recibe los datos con fines de análisis científico o epidemiológico; en el segundo, una entidad toma la iniciativa de hacer públicos los datos de forma accesible y coherente. Los autores exponen en detalle un ejemplo del segundo procedimiento, a saber, el sitio web de información sobre la tuberculosis bovina (https://ibtb.co.uk) en libre acceso, en el cual se publican datos sobre la enfermedad dirigidos a los profesionales del sector pecuario y la sanidad animal.

A study of the incidence of bovine tuberculosis in the wild red deer herd of Exmoor.

Bovine tuberculosis (bTB) is an infectious disease which thrives at the wildlife-livestock interface. Exmoor has the largest herd of wild red deer (Cervus elaphus) in England, and also a large number of dairy and beef farms. The population, health and well-being of the herd are managed by a combination of hunting with hounds and by stalking. This study used a serological assay to determine the incidence of bTB in the population of 106 wild red deer of Exmoor, the relationship between regional deer densities and the presence of bTB in deer, and domestic cattle. The overall number of bTB positive deer was 28.3% (30/106). Stalked deer had a slightly higher incidence of bTB (19 out of 55, 34.55%) than hunted deer (11 out of 51, 21.57%). There was no clear pattern of distribution except for one region which showed an incidence of 42.22% compared with 16.4% in the remainder of the moor. There was little difference in the incidence of bTB between male and female animals. The age of animals in the study ranged from < 1 year to over 10 years. There was no clear difference in the incidence across the age range (< 1 year- > 10 years) with the exception of a particularly high incidence in those animals aged 1 year or less. There was a significant correlation between the presence of deer with bTB and the number of farms reporting bTB positive cattle, but not between the regional population of red deer and bTB in deer or cattle.

Transcriptional Profiling of Early and Late Phases of Bovine Tuberculosis.

Bovine tuberculosis, caused by Mycobacterium tuberculosis var. bovis (M. bovis), is an important enzootic disease affecting mainly cattle, worldwide. Despite the implementation of national campaigns to eliminate the disease, bovine tuberculosis remains recalcitrant to eradication in several countries. Characterizing the host response to M. bovis infection is crucial for understanding the immunopathogenesis of the disease and for developing better control strategies. To profile the host responses to M. bovis infection, we analyzed the transcriptome of whole blood cells collected from experimentally infected calves with a virulent strain of M. bovis using RNA transcriptome sequencing (RNAseq). Comparative analysis of calf transcriptomes at early (8 weeks) versus late (20 weeks) aerosol infection with M. bovis revealed a divergent and unique profile for each stage of infection. Notably, at the early time point, transcriptional upregulation was observed among several of the top-ranking canonical pathways involved in T-cell chemotaxis. At the late time point, enrichment in the cell mediated cytotoxicity (e.g., Granzyme B) was the predominant host response. These results showed significant change in bovine transcriptional profiles and identified networks of chemokine receptors and monocyte chemoattractant protein (CCL) coregulated genes that underline the host-mycobacterial interactions during progression of bovine tuberculosis in cattle. Further analysis of the transcriptomic profiles identified potential biomarker targets for early and late phases of tuberculosis in cattle. Overall, the identified profiles better characterized identified novel immunomodulatory mechanisms and provided a list of targets for further development of potential diagnostics for tuberculosis in cattle.

Untargeted metabolomic analysis of thoracic blood from badgers indicate changes linked to infection with bovine tuberculosis (Mycobacterium bovis): a pilot study.

INTRODUCTION: Mycobacterium bovis, the causative agent of bovine tuberculosis (bTB) in cattle, represents a major disease burden to UK cattle farming, with considerable costs associated with its control. The European badger (Meles meles) is a known wildlife reservoir for bTB and better knowledge of the epidemiology of bTB through testing wildlife is required for disease control. Current tests available for the diagnosis of bTB in badgers are limited by cost, processing time or sensitivities. MATERIALS AND METHODS: We assessed the ability of flow infusion electrospray-high-resolution mass spectrometry (FIE-HRMS) to determine potential differences between infected and non-infected badgers based on thoracic blood samples obtained from badgers found dead in Wales. Thoracic blood samples were autoclaved for handling in a containment level 2 (CL2) hazard laboratory. RESULTS: Here we show the major differences associated with with M. bovis infection were changes to folate, pyrimidine, histidine, glycerophospholipid and phosphonate metabolism. CONCLUSIONS: Our studies have indicated differences in the metabolomic signature of badgers found dead in relation to their infection status, suggesting metabolomics could hold potential for developing novel diagnostics for bTB in badgers. As well as highlighting a potential way to handle samples containing a highly pathogenic agent at CL2 for metabolomics studies.

A Bayesian evolutionary model towards understanding wildlife contribution to F4-family Mycobacterium bovis transmission in the South-West of France.

In two "départements" in the South-West of France, bovine tuberculosis (bTB) outbreaks due to Mycobacterium bovis spoligotype SB0821 have been identified in cattle since 2002 and in wildlife since 2013. Using whole genome sequencing, the aim of our study was to clarify badger contribution to bTB transmission in this area. We used a Bayesian evolutionary model, to infer phylogenetic trees and migration rates between two pathogen populations defined by their host-species. In order to account for sampling bias, sub-population structure was inferred using the marginal approximation of the structured coalescent (Mascot) implemented in BEAST2. We included 167 SB0821 strains (21 isolated from badgers and 146 from cattle) and identified 171 single nucleotide polymorphisms. We selected a HKY model and a strict molecular clock. We estimated a badger-to-cattle transition rate (median: 2.2 transitions/lineage/year) 52 times superior to the cattle-to-badger rate (median: 0.042 transitions/lineage/year). Using the maximum clade credibility tree, we identified that over 75% of the lineages from 1989 to 2000 were present in badgers. In addition, we calculated a median of 64 transition events from badger-to-cattle (IQR: 10-91) and a median of zero transition event from cattle-to-badger (IQR: 0-3). Our model enabled us to infer inter-species transitions but not intra-population transmission as in previous epidemiological studies, where relevant units were farms and badger social groups. Thus, while we could not confirm badgers as possible intermediaries in farm-to-farm transmission, badger-to-cattle transition rate was high and we confirmed long-term presence of M. bovis in the badger population in the South-West of France.

Northern Ireland farm-level management factors for recurrent bovine tuberculosis herd breakdowns.

Bovine tuberculosis (bTB) is a chronic, infectious and zoonotic disease of domestic and wild animals caused mainly by Mycobacterium bovis. This study investigated farm management factors associated with recurrent bTB herd breakdowns (n = 2935) disclosed in the period 23 May 2016 to 21 May 2018 and is a follow-up to our 2020 paper which looked at long duration bTB herd breakdowns. A case control study design was used to construct an explanatory set of farm-level management factors associated with recurrent bTB herd breakdowns. In Northern Ireland, a Department of Agriculture Environment and Rural Affairs (DAERA) Veterinarian investigates bTB herd breakdowns using standardised guidelines to allocate a disease source. In this study, source was strongly linked to carryover of infection, suggesting that the diagnostic tests had failed to clear herd infection during the breakdown period. Other results from this study associated with recurrent bTB herd breakdowns were herd size and type (dairy herds 43% of cases), with both these variables intrinsically linked. Other associated risk factors were time of application of slurry, badger access to silage clamps, badger setts in the locality, cattle grazing silage fields immediately post-harvest, number of parcels of land the farmer associated with bTB, number of land parcels used for grazing and region of the country.

Mycobacterium bovis induced human tuberculosis in India: Current status, challenges & opportunities.

Tuberculosis (TB) caused by Mycobacterium tuberculosis is a leading cause of human deaths due to any infectious disease worldwide. However, infection of Mycobacterium bovis, primarily an animal pathogen, also leads to the development of 'human tuberculosis'. Infected animals have been considered the major source of M. bovis infection and humans get exposed to M. bovis through close contact with infected animals or consumption of contaminated milk, unpasteurized dairy products and improperly cooked contaminated meat. The information on the global distribution of bovine TB (bTB) is limited, but the disease has been reported from all the livestock-producing middle- and low-income countries of the world. In recent years, there is a renewed interest for the control of bTB to minimize human infection worldwide. In India, while the sporadic presence of M. bovis has been reported in domestic animals, animal-derived food products and human beings from different geographical regions of the country, the information on the national prevalence of bTB and transmission dynamics of zoonotic TB is, however, not available. The present article reviewed published information on the status of M. bovis-induced zoonotic TB to highlight the key challenges and opportunities for intervention to minimize the risk of M. bovis infection in humans and secure optimum animal productivity in India.

Milk and meat consumption patterns and the potential risk of zoonotic disease transmission among urban and peri-urban dairy farmers in Ethiopia.

BACKGROUND: In the Ethiopian dairy farming system, prevalence of zoonotic diseases such as bovine tuberculosis (bTB) is high in the cattle population. This, combined with some risky milk and meat consumption habits, such as raw milk and uninspected raw meat consumption, poses a considerable risk of zoonotic disease transmission. A survey was conducted to investigate milk and meat consumption patterns, and the level of exposure to urban and peri-urban dairy-keeping households for risks of zoonotic disease transmission. METHODS: Data on milk and meat consumption behaviours and other socioeconomic and demographic variables were collected from 480 urban and peri-urban dairy farms randomly surveyed in major towns in Ethiopia (Mekele, Hawassa, and Gondar towns, Addis Ababa city, as well as five Oromia towns around Addis Ababa). Determinants of raw milk consumption associated with a number of demographic and socio-economic factors were analysed using a generalised ordered logistic model. RESULTS: The results indicated that about 20% the population consumed raw milk and their awareness about pasteurisation and its benefits were low. Location, gender of the household head, previous bTB testing of cattle on the farm, knowledge of zoonotic risks associated with raw milk consumption, household size, and per-capita milk consumption were found to be important determinants of the frequency of raw milk consumption. About 60% of the respondents were exposed to the risk of zoonotic diseases through their habit of frequently consuming raw meat. This was despite that over 90% of the respondents were aware of possible zoonotic risks of raw meat consumption. The determinants of raw meat consumption behaviours were associated with location, gender and age of the household head, household size, meat type preference, per-capita meat consumption, knowledge about disease transmission risks, and training on zoonoses. CONCLUSION: Creating awareness about the risk factors for zoonotic transmission of diseases through training and media campaigns, improving meat hygiene through better abattoir services, and inducing behavioural change around meat sourcing, raw meat and raw milk consumption, are all crucial to the successful prevention and control of the spread of zoonotic diseases, including bTB.