Tuberculosis in domestic animal species

Integrative and comparative genomic analyses of mammalian macrophage responses to intracellular mycobacterial pathogens

Mycobacterium tuberculosis, the causative agent of human tuberculosis (hTB), is a close evolutionary relative of Mycobacterium bovis, which causes bovine tuberculosis (bTB), one of the most damaging infectious diseases to livestock agriculture. Previous studies have shown that the pathogenesis of bTB disease is comparable to hTB disease, and that the bovine and human alveolar macrophage (bAM and hAM, respectively) transcriptomes are extensively reprogrammed in response to infection with these intracellular mycobacterial pathogens. In this study, a multi-omics integrative approach was applied with functional genomics and GWAS data sets across the two primary hosts (Bos taurus and Homo sapiens) and both pathogens (M. bovis and M. tuberculosis). Four different experimental infection groups were used: 1) bAM infected with M. bovis, 2) bAM infected with M. tuberculosis, 3) hAM infected with M. tuberculosis, and 4) human monocyte-derived macrophages (hMDM) infected with M. tuberculosis. RNA-seq data from these experiments 24 h post-infection (24 hpi) was analysed using three computational pipelines: 1) differentially expressed genes, 2) differential gene expression interaction networks, and 3) combined pathway analysis. The results were integrated with high-resolution bovine and human GWAS data sets to detect novel quantitative trait loci (QTLs) for resistance to mycobacterial infection and resilience to disease. This revealed common and unique response macrophage pathways for both pathogens and identified 32 genes (12 bovine and 20 human) significantly enriched for SNPs associated with disease resistance, the majority of which encode key components of the NF-κB signalling pathway and that also drive formation of the granuloma.

Worldwide Swine Tuberculosis-Positive Rate and Associated Risk Factors, 1966-2020: A Systematic Review and Meta-Analysis

Background: Tuberculosis (TB) is a chronic, zoonotic infectious disease caused by Mycobacterium tuberculosis that infects not only humans but also animals such as pigs, cows, buffaloes, sheep, and goats. Among them, pigs are one of the main food animals in the world. If pigs are infected with M. tuberculosis, meat products will be negatively affected, causing economic losses to the livestock industry. There is currently no systematic epidemiological assessment of swine TB in the world, so it is important to know the prevalence of swine, and these data are currently lacking, so we performed a statistical analysis. Results: We searched 6791 articles and finally included data from 35,303 pigs from 15 countries or territories, showing a combined prevalence of TB in pigs of 12.1% (95% confidence interval [CI]: 9.2 to 15.9). Among them, the prevalence rate of swine TB in Europe was 15.2% (95% CI: 11.1 to 20.7, 2491/25,050), which was higher compared with other continents, and the difference was significant; the positive rate of PCR method was higher in the detection method subgroup, which was 15.7% (95% CI: 8.0 to 31.0, 376/2261); Mycobacterium bovis was detected in pigs in the M. tuberculosis typing group (9.5%, 95% CI: 6.7 to 13.5, 1364/21,430). The positive rate is higher compared with Mycobacterium capris. Conclusion: This systematic review and meta-analysis is the first to determine the global prevalence of TB in swine herds. Although the seroprevalence of swine TB in this article is very low, the harm of TB cannot be ignored. It is important to take effective control and preventive measures to stop the spread of TB to reduce the impact of diseased pigs on animal husbandry and human health.

Detection of Mycobacterium bovis in nasal swabs from communal goats (Capra hircus) in rural KwaZulu-Natal, South Africa

Animal tuberculosis, caused by Mycobacterium bovis, presents a significant threat to both livestock industries and public health. Mycobacterium bovis tests rely on detecting antigen specific immune responses, which can be influenced by exposure to non-tuberculous mycobacteria, test technique, and duration and severity of infection. Despite advancements in direct M. bovis detection, mycobacterial culture remains the primary diagnostic standard. Recent efforts have explored culture-independent PCR-based methods for identifying mycobacterial DNA in respiratory samples. This study aimed to detect M. bovis in nasal swabs from goats (Capra hircus) cohabiting with M. bovis-infected cattle in KwaZulu-Natal, South Africa. Nasal swabs were collected from 137 communal goats exposed to M. bovis-positive cattle and 20 goats from a commercial dairy herd without M. bovis history. Swabs were divided into three aliquots for analysis. The first underwent GeneXpert® MTB/RIF Ultra assay (Ultra) screening. DNA from the second underwent mycobacterial genus-specific PCR and Sanger sequencing, while the third underwent mycobacterial culture followed by PCR and sequencing. Deep sequencing identified M. bovis DNA in selected Ultra-positive swabs, confirmed by region-of-difference (RD) PCR. Despite no other evidence of M. bovis infection, viable M. bovis was cultured from three communal goat swabs, confirmed by PCR and sequencing. Deep sequencing of DNA directly from swabs identified M. bovis in the same culture-positive swabs and eight additional communal goats. No M. bovis was found in commercial dairy goats, but various NTM species were detected. This highlights the risk of M. bovis exposure or infection in goats sharing pastures with infected cattle. Rapid Ultra screening shows promise for selecting goats for further M. bovis testing. These techniques may enhance M. bovis detection in paucibacillary samples and serve as valuable research tools.

[Tuberculosis Infection Control & Hygiene - Recommendations of the DZK]

Preventing the spread of the disease is an essential goal in the care and treatment of tuberculosis. In addition to early diagnosis and effective therapies, isolation of infectious patients and adequate hygiene measures are of particular importance for infection prevention. The present recommendations replace the previous recommendations "tuberculosis infection control" from 2012 and take into account the current national and international recommendations and as well as new scientific findings. After a description of the infection and the transmission pathways, the necessary prevention and hygiene measures in health care facilities are comprehensively presented. Since the last revision of the recommendations on infection prevention, international recommendations and the KRINKO recommendation on ending isolation have been changed. In accordance with this, under certain conditions in the case of sensitive tuberculosis, de-isolation in health care facilities can take place after 14 days without taking the sputum findings into account. The second part of the recommendations explains in detail the measures to be taken in special situations and areas, such as general practitioners, ambulance services and care facilities. Here, the recommendations on respiratory protection have been simplified; for staff, an FFP2 mask is now generally considered sufficient.

Characterization of mycophage endolysin cell wall binding domains targeting Mycobacterium bovis peptidoglycan

Mycophage endolysins are highly diverse and modular enzymes composed of domains involved in peptidoglycan binding and degradation. Mostly, they are characterized by a three-module design: an N-terminal peptidase domain, a central catalytic domain and a C-terminal peptidoglycan binding domain. Previously, the affinity of cell wall binding domains (CBDs) to the mycobacterial peptidoglycan layer was shown for some of these endolysins. In this study, an in depth screening was performed on twelve mycophage endolysins. The discovered CBDs were characterized for their binding affinity to Mycobacterium (M.) bovis bacille Calmette-Guérin (BCG), a largely unexplored target and an attenuated strain of M. bovis, responsible for bovine tuberculosis. Using homology-based annotation, only four endolysins showed the presence of a known peptidoglycan binding domain, the previously characterized pfam 01471 domain. However, analysis of the secondary structure aided by AlphaFold predictions revealed the presence of a C-terminal domain in the other endolysins. These were hypothesized as new, uncharacterized CBDs. Fusion proteins composed of these domains linked to GFP were constructed and positively assayed for their affinity to M. bovis BCG in a peptidoglycan binding assay. Moreover, two CBDs were able to fluorescently label M. bovis BCG in milk samples, highlighting the potential to further explore their possibility to function as CBD-based diagnostics.

Detection of Mycobacterium tuberculosis complex field infections in cattle using fecal volatile organic compound analysis through gas chromatography-ion mobility spectrometry combined with chemometrics

Bovine tuberculosis is considered a re-emerging disease caused by different species from the Mycobacterium tuberculosis complex (MTC), important not only for the livestock sector but also for public health due to its zoonotic character. Despite the numerous efforts that have been carried out to improve the performance of the current antemortem diagnostic procedures, nowadays, they still pose several drawbacks, such as moderate to low sensitivity, highlighting the necessity to develop alternative and innovative tools to complement control and surveillance frameworks. Volatilome analysis is considered an innovative approach which has been widely employed in animal science, including animal health field and diagnosis, due to the useful and interesting information provided by volatile metabolites. Therefore, this study assesses the potential of gas chromatography coupled to ion mobility spectrometry (GC-IMS) to discriminate cattle naturally infected (field infections) by MTC from non-infected animals. Volatile organic compounds (VOCs) produced from feces were analyzed, employing the subsequent information through chemometrics. After the evaluation of variable importance for the projection of compounds, the final discriminant models achieved a robust performance in cross-validation, as well as high percentages of correct classification (>90%) and optimal data of sensitivity (91.66%) and specificity (99.99%) in external validation. The tentative identification of some VOCs revealed some coincidences with previous studies, although potential new compounds associated with the discrimination of infected and non-infected subjects were also addressed. These results provide strong evidence that a volatilome analysis of feces through GC-IMS coupled to chemometrics could become a valuable methodology to discriminate the infection by MTC in cattle. IMPORTANCE Bovine tuberculosis is endemic in many countries worldwide and poses important concerns for public health because of their zoonotic condition. However, current diagnostic techniques present several hurdles, such as low sensitivity and complexity, among others. In this regard, the development of new approaches to improve the diagnosis and control of this disease is considered crucial. Volatile organic compounds are small molecular mass metabolites which compose volatilome, whose analysis has been widely employed with success in different areas of animal science including animal health. The present study seeks to evaluate the combination of fecal volatilome analysis with chemometrics to detect field infections by bovine tuberculosis (Mycobacterium tuberculosis complex) in cattle. The good robust performance of discriminant models as well as the optimal data of sensitivity and specificity achieved highlight volatilome analysis as an innovative approach with huge potential.

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: OD_bovis-OD_PBS ≥ 0.1 and OD_bovis-OD_avium ≥ 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.

Seroepidemiology of tuberculosis in sheep in southern Spain

Tuberculosis (TB) is a multi-host infectious disease caused by members of the Mycobacterium tuberculosis complex (MTC). In Mediterranean ecosystems, where multiple animal hosts of TB are present, identifying the role of the different species involved in the epidemiology of TB is a key point to be able to implement proper control measures. Sheep are susceptible to MTC infection but have traditionally been considered a spillover host. However, the occurrence of outbreaks involving sheep in recent years evidences the need to better understand the role of this small ruminant species in the epidemiology of the disease. Here, we aimed to determine the seroprevalence and risk factors associated with MTC seropositivity in sheep in Andalusia (southern Spain), a region with one of the highest prevalence of MTC infection in both cattle and wild ungulates. A total of 2266 sheep from 83 flocks were tested for antibodies against MTC using an in-house indirect ELISA. Anti-MTC antibodies were detected in 16 (0.7%) of the 2266 sheep (adjusted true prevalence 0.29%, 95% posterior probability interval 0.01-1.05). Seropositivity was found in 14.5% (12/83; 95%CI: 6.9-22.0) of the sheep farms analyzed. A semi-extensive management system was identified as a risk factor associated with MTC seropositivity in sheep farms (OR = 3.7; p < 0.038; 95%CI: 1.1-12.4) in the study area. To the best of the authors' knowledge, this is the first active TB surveillance study carried out to assess MTC exposure in sheep. Our results indicate MTC circulation in sheep farms in southern Spain. However, the low individual seroprevalence obtained suggests that sheep may play a limited role in the epidemiology of TB in this region. Serosurveillance programs could be a valuable tool to detect MTC circulation in sheep in risk scenarios or target farms, in order to optimize control measures on TB animal in multi-host Mediterranean ecosystems.

Safety and Immunogenicity of Recombinant Bacille Calmette-Guérin Strain VPM1002 and Its Derivatives in a Goat Model

A more effective vaccine against tuberculosis than Bacille Calmette-Guérin (BCG) is urgently needed. BCG derived recombinant VPM1002 has been found to be more efficacious and safer than the parental strain in mice models. Newer candidates, such as VPM1002 Δpdx1 (PDX) and VPM1002 ΔnuoG (NUOG), were generated to further improve the safety profile or efficacy of the vaccine. Herein, we assessed the safety and immunogenicity of VPM1002 and its derivatives, PDX and NUOG, in juvenile goats. Vaccination did not affect the goats’ health in regards to clinical/hematological features. However, all three tested vaccine candidates and BCG induced granulomas at the site of injection, with some of the nodules developing ulcerations approximately one month post-vaccination. Viable vaccine strains were cultured from the injection site wounds in a few NUOG- and PDX- vaccinated animals. At necropsy (127 days post-vaccination), BCG, VPM1002, and NUOG, but not PDX, still persisted at the injection granulomas. All strains, apart from NUOG, induced granuloma formation only in the lymph nodes draining the injection site. In one animal, the administered BCG strain was recovered from the mediastinal lymph nodes. Interferon gamma (IFN-γ) release assay showed that VPM1002 and NUOG induced a strong antigen-specific response comparable to that elicited by BCG, while the response to PDX was delayed. Flow cytometry analysis of IFN-γ production by CD4+, CD8+, and γδ T cells showed that CD4+ T cells of VPM1002- and NUOG-vaccinated goats produced more IFN-γ compared to BCG-vaccinated and mock-treated animals. In summary, the subcutaneous application of VPM1002 and NUOG induced anti-tuberculous immunity, while exhibiting a comparable safety profile to BCG in goats.

Mycobacterium tuberculosis complex detection in rural goat herds in South Africa using Bayesian latent class analysis

Animal tuberculosis affects a wide range of domestic and wild animal species, including goats (Capra hircus). In South Africa, Mycobacterium tuberculosis complex (MTBC) testing and surveillance in domestic goats is not widely applied, potentially leading to under recognition of goats as a potential source of M. bovis spread to cattle as well as humans and wildlife. The aim of this study was to estimate diagnostic test performance for four assays and determine whether M. bovis infection was present in goats sharing communal pastures with M. bovis positive cattle in the Umkhanyakude district of Northern Zululand, KwaZulu Natal. In 2019, 137 M. bovis-exposed goats were screened for MTBC infection with four diagnostic tests: the in vivo single intradermal comparative cervical tuberculin test (SICCT), in vitro QuantiFERON®-TB Gold (QFT) bovine interferon-gamma release assay (IGRA), QFT bovine interferon gamma induced protein 10 (IP-10) release assay (IPRA), and nasal swabs tested with the Cepheid GeneXpert® MTB/RIF Ultra (GXU) assay for detection of MTBC DNA. A Bayesian latent class analysis was used to estimate MTBC prevalence and diagnostic test sensitivity and specificity. Among the 137 M. bovis-exposed goats, positive test results were identified in 15/136 (11.0%) goats by the SICCT; 4/128 (3.1%) goats by the IPRA; 2/128 (1.6%) goats by the IGRA; and 26/134 (19.4%) nasal swabs by the GXU. True prevalence was estimated by our model to be 1.1%, suggesting that goats in these communal herds are infected with MTBC at a low level. Estimated posterior means across the four evaluated assays ranged from 62.7% to 80.9% for diagnostic sensitivity and from 82.9% to 97.9% for diagnostic specificity, albeit estimates of the former (diagnostic sensitivity) were dependent on model assumptions. The application of a Bayesian latent class analysis and multiple ante-mortem test results may improve detection of MTBC, especially when prevalence is low. Our results provide a foundation for further investigation to confirm infection in communal goat herds and identify previously unrecognized sources of intra- and inter-species transmission of MTBC.

Development of a safety protocol for training and using SARS-CoV-2 detection dogs: A pilot study

Medical detection dogs have potential to be used to screen asymptomatic patients in crowded areas at risk of epidemics such as the SARS-CoV-2 pandemic. However, the fact that SARS-CoV-2 detection dogs are in direct contact with infected people or materials raises important concerns due to the zoonotic potential of the virus. No study has yet recommended a safety protocol to ensure the health of SARS- CoV-2 detection dogs during training and working in public areas. This study sought to identify suitable decontamination methods to obtain nonpathogenic face mask samples while working with SARS-CoV-2 detection dogs and to investigate whether dogs were able to adapt themselves to other decontamination procedures once they were trained for a specific odor. The present study was designed as a four-phase study: (a) Method development, (b) Testing of decon- tamination methods, (c) Testing of training methodology, and (d) Real life scenario. Surgical face masks were used as scent samples. In total, 3 dogs were trained. The practical use of 3 different decontam- ination procedures (storage, heating, and UV-C light) while training SARS-CoV-2 detection dogs were tested. The dog trained for the task alerted to the samples inactivated by the storage method with a sensitivity of100 % and specificity of 98.28 %. In the last phase of this study, one dog of 2 dogs trained, alerted to the samples inactivated by the UV-C light with a sensitivity of 91.30% and specificity of 97.16% while the other dog detected the sample with a sensitivity of 96.00% and specificity of 97.65 %.

The safety of BCG vaccination in cattle: results from good laboratory practice safety studies in calves and lactating cows

Bovine tuberculosis (bTB) is a global disease of livestock that has damaging economic, animal health and public health consequences. Conventional bTB disease control strategies, based around the testing and slaughter of cattle infected with bTB, are typically used to help limit or reduce the transmission of this disease but in many low- and middle-income countries such strategies may often be economically unviable, culturally unacceptable or logistically impracticable. The use of vaccination to protect cattle against bTB could provide a potentially more affordable, ethically acceptable and practical additional disease control measure. The protective efficacy of the commercially produced and readily available human vaccine against tuberculosis (Mycobacterium bovis Bacille Calmette-Guérin; BCG) in cattle has been demonstrated in many experimental laboratory and field studies. However, Good Laboratory Practice (GLP) studies assessing the safety of BCG vaccination in cattle have not previously been reported. We describe here the results of two GLP safety studies in which calves and lactating cows were vaccinated with BCG (Danish 1331 strain). From an animal health and welfare perspective, the results of these studies indicate that BCG vaccine is well tolerated in these categories of cattle with only transient and minor local or systemic reactions. Furthermore, there was no evidence that BCG was shed in raw milk, saliva or faeces collected from vaccinates and vaccination did not have a detrimental effect on milk yields in lactating cattle. These data, underpinned by GLP principles, further support the existing data on the safety of BCG vaccine in cattle and complement the abundant available cattle efficacy data for this potential cattle bTB vaccine.

Effect of a recent parenteral dexamethasone and ketoprofen administration on the immunological diagnosis of tuberculosis in goats

Caprine tuberculosis (TB) is a zoonosis caused by members of the Mycobacterium tuberculosis complex (MTBC). Caprine TB eradication programmes are based mainly on intradermal tuberculin tests and slaughterhouse surveillance. Different factors may affect the performance of the TB diagnostic tests used in caprine herds and, therefore, their ability to detect infected animals. The present study evaluates the effect of the fraudulent administration of two anti-inflammatory substances, dexamethasone and ketoprofen, on the performance of the TB diagnostic techniques used in goats, as well as the suitability of high performance liquid chromatography (HPLC) for their detection in hair samples. The animals (n = 90) were distributed in three groups: (1) a group treated with dexamethasone (n = 30); a second group treated with ketoprofen (n = 30); and a third non-treated control group (n = 30). Both dexamethasone and ketoprofen groups were subjected to intramuscular inoculation with the substances 48 h after the administration of bovine and avian purified protein derivatives (PPDs), that is, 24 h before the tests were interpreted. All the animals were subjected to the single and comparative intradermal tuberculin (SIT and CIT, respectively) tests, interferon-gamma release assay (IGRA) and P22 ELISA. The number of SIT test reactors was significantly lower in the dexamethasone (p = 0.001) and ketoprofen (p &lt; 0.001) groups 72 h after the bovine PPD inoculation compared with the control group. A significantly higher number of positive reactors to IGRA was detected within the dexamethasone group (p = 0.016) 72 h after PPD administration compared to the control group. Dexamethasone and ketoprofen detection in either hair or serum samples was challenging when using HPLC since these substances were not detected in animals whose skin fold thickness (SFT) was reduced, what could be an issue if they are used for fraudulent purposes. In conclusion, the parenteral administration of dexamethasone or ketoprofen 48 h after the PPDs administration can significantly reduce the increase in SFT (mm) and subsequently the number of positive reactors to SIT test.

KLK12 Regulates MMP-1 and MMP-9 via Bradykinin Receptors: Biomarkers for Differentiating Latent and Active Bovine Tuberculosis

It has been established that kallikrein12 (KLK12) expression is closely related to bovine tuberculosis (bTB) development. Herein, we sought to clarify the regulatory mechanism of KLK12 and its application in tuberculosis diagnosis. KLK12 knockdown macrophages were produced by siRNA transfection. Bradykinin receptors (BR, including B1R and B2R) were blocked with specific inhibitors. Mannose-capped lipoarabinomannan (ManLAM) was extracted from Mycobacterium bovis (M. bovis) and used to study the mechanism of KLK12 activation. In addition, we constructed different mouse models representing the latent and active stages of M. bovis infection. Mouse models and clinical serum samples were used to assess the diagnostic value of biomarkers. Through the above methods, we confirmed that KLK12 regulates MMP-1 and MMP-9 via BR. KLK12 upregulation is mediated by the M. bovis-specific antigen ManLAM. KLK12, MMP-1, and MMP-9 harbor significant value as serological markers for differentiating between latent and active bTB, especially KLK12. In conclusion, we identified a novel signaling pathway, KLK12/BR/ERK/MMPs, in M. bovis-infected macrophages, which is activated by ManLAM. From this signaling pathway, KLK12 can be used as a serological marker to differentiate between latent and active bTB. Importantly, KLK12 also has enormous potential for the clinical diagnosis of human tuberculosis (TB).

Field evaluation of the tuberculin skin test for the detection of Mycobacterium tuberculosis complex infection in communal goats (Capra hircus) in KwaZulu-Natal, South Africa

In South Africa, animal tuberculosis (TB) control programs predominantly focus on domestic cattle and African buffaloes (Syncerus caffer) despite increasing global reports of tuberculosis in goats (Capra hircus). Left undetected, Mycobacterium tuberculosis complex (MTBC) infected goats may hinder TB eradication efforts in cattle and increase zoonotic risk to humans. Since the publication of animal TB testing guidelines in 2018, prescribing the use of the tuberculin skin test (TST) for goats in South Africa by the Department of Agriculture, Land Reform, and Rural Development (DALRRD), there have been no published reports of any field application of the prescribed test criteria in goat herds. Therefore, this study aimed to evaluate the performance of these DALRRD guidelines using the single intradermal cervical tuberculin test (SICT) and the single intradermal comparative cervical tuberculin test (SICCT). Between October and December 2020, 495 goats from communal pastures of Kwa-Zulu Natal (KZN), where M. bovis infection has been identified in cattle and where cattle and goats cohabitate, were tested using the SICT and SICCT (M. bovis-exposed group). Additionally, 277 goats from a commercial Saanen dairy herd, with no history of M. bovis, were also tested (M. bovis-unexposed group). Estimated apparent prevalence of TST positive goats was determined based on published test interpretation criteria as described by DALRRD. When proportions of test-positive goats were compared between different DALRRD criteria, the ≥ 4 mm cut-off criterion for the SICCT resulted in the lowest proportion of positive results in the presumably uninfected group (1/277 positive in the unexposed group). The apparent prevalence of TB in the exposed group was estimated at 3.0% (95% CI: 1.7-4.9%), which is similar to previous reports of M. bovis prevalence in cattle from this area (6%). The detection of a significantly greater proportion of SICCT positive goats in the M. bovis-exposed group compared to the unexposed group suggests that MTBC infection is present in this population. Further investigations should be undertaken, in conjunction with confirmatory molecular tests, mycobacterial culture, and advanced pathogen sequencing to establish whether MTBC infection in domestic goats is a true under-recognized threat to the eradication of animal TB in South Africa.

Vaccine-Induced Subcutaneous Granulomas in Goats Reflect Differences in Host–Mycobacterium Interactions between BCG- and Recombinant BCG-Derivative Vaccines

Tuberculous granulomas are highly dynamic structures reflecting the complex host–mycobacterium interactions. The objective of this study was to compare granuloma development at the site of vaccination with BCG and its recombinant derivatives in goats. To characterize the host response, epithelioid cells, multinucleated giant cells (MNGC), T cell subsets, B cells, plasma cells, dendritic cells and mycobacterial antigen were labelled by immunohistochemistry, and lipids and acid-fast bacteria (AFB) were labelled by specific staining. Granulomas with central caseous necrosis developed at the injection site of most goats though lesion size and extent of necrosis differed between vaccine strains. CD4⁺ T and B cells were more scarce and CD8⁺ cells were more numerous in granulomas induced by recombinant derivatives compared to their parental BCG strain. Further, the numbers of MNGCs and cells with lipid bodies were markedly lower in groups administered with recombinant BCG strains. Microscopic detection of AFB and mycobacterial antigen was rather frequent in the area of central necrosis, however, the isolation of bacteria in culture was rarely successful. In summary, BCG and its recombinant derivatives induced reproducibly subcutaneous caseous granulomas in goats that can be easily monitored and surgically removed for further studies. The granulomas reflected the genetic modifications of the recombinant BCG-derivatives and are therefore suitable models to compare reactions to different mycobacteria or TB vaccines.

Evidence, Challenges, and Knowledge Gaps Regarding Latent Tuberculosis in Animals

Mycobacterium bovis and other Mycobacterium tuberculosis complex (MTBC) pathogens that cause domestic animal and wildlife tuberculosis have received considerably less attention than M. tuberculosis, the primary cause of human tuberculosis (TB). Human TB studies have shown that different stages of infection can exist, driven by host–pathogen interactions. This results in the emergence of heterogeneous subpopulations of mycobacteria in different phenotypic states, which range from actively replicating (AR) cells to viable but slowly or non-replicating (VBNR), viable but non-culturable (VBNC), and dormant mycobacteria. The VBNR, VBNC, and dormant subpopulations are believed to underlie latent tuberculosis (LTB) in humans; however, it is unclear if a similar phenomenon could be happening in animals. This review discusses the evidence, challenges, and knowledge gaps regarding LTB in animals, and possible host–pathogen differences in the MTBC strains M. tuberculosis and M. bovis during infection. We further consider models that might be adapted from human TB research to investigate how the different phenotypic states of bacteria could influence TB stages in animals. In addition, we explore potential host biomarkers and mycobacterial changes in the DosR regulon, transcriptional sigma factors, and resuscitation-promoting factors that may influence the development of LTB.

One Health risk challenges and preparedness regarding bovine tuberculosis at abattoirs in North-central Nigeria: Associated drivers and health belief

Background

Bovine tuberculosis (bTB) is a serious public health and neglected zoonotic disease responsible for 147,000 human cases and 12,500 deaths annually. This study assessed knowledge, risk perceptions, and preventive practices regarding bTB among occupationally exposed abattoir workers and drivers for transmission in slaughterhouses.

Methods

Using a pre-tested questionnaire, we surveyed a cross-section of workers in five main abattoirs in North-central Nigeria between 2018 and 2019. Data were analysed using descriptive statistics and univariable/multivariable logistic regression analyses at a 95% confidence level.

Results

All recruited respondents (n = 422: 77.7% meat processors and 22.3% meat and sanitary inspectors) participated and 10.4% had no formal education. About 44.0% and 27.0% of workers knew about bTB occurrence at the abattoirs and its transmission to humans, respectively. Less than one-third use personal protective equipment (PPE) during meat handling, only a few workers correctly practised routine handwashing, and 21.8% sterilized meat handling tools. A few participants (6.4%) had BCG vaccination against tuberculosis. Demographic characteristics (age, gender, occupation, and formal education) significantly influenced the perception and practices about bTB. A few workers perceived raw meat and milk, direct contact with infected carcasses, organs and contaminated fomites, contaminated environment through infected blood, dirty slaughtering floor, and aerosols of contaminated faeces as high-risk bTB transmission routes. Perceived drivers that influenced bTB transmission at abattoirs include unhygienic meat processing (OR = 5.4, 95%CI = 3.1–9.4, p < 0.001) and non-enforcement of abattoir standard operating systems (OR = 10.4, 95%CI = 6.0–18.5, p = 0.001).

Conclusion

The workers have low knowledge levels, perceptions, and practices toward bTB emergence. These demand the workers’ education on hygienic meat handling to mitigate the menace of the disease. Surveillance and preventive preparedness considering the identified drivers through the ’One Health’ approach are recommended.

Isolation of multidrug-resistant (MDR) Mycobacterium bovis from a dog in Korea

A 3-year-old female Miniature Schnauzer dog with a week-long history of generalized intention tremor and progressive weight loss for several months was admitted. Mild anemia, fever, splenomegaly, aseptic cerebral meningitis and systemic lymph nodes enlargement were examined through erythrogram, ultrasonography, computed tomography and magnetic resonance imaging. Mycobacterium bovis was identified via molecular microbiology having the same molecular type as that of isolates from a cattle farm previously identified. However, the dog was raised in a city. The M. bovis had multidrug resistance (MDR)-bearing mutations in both katG and rpoB genes toward first-line antibiotics. To the best of our knowledge, this is the first report describing an MDR M. bovis infection of a dog in Korea.

MGIT sensitivity testing and genotyping of drug resistant Mycobacterium tuberculosis isolates from Mizoram, Northeast India

PURPOSE

Tuberculosis, a crucial infectious disease is still a health concern globally. India is among the countries with high MDR-TB burden. Currently, sputum smear microscopy using Ziehl Neelsen stain and GeneXpert are the only diagnostic means in Mizoram. This study was done to characterize local tuberculosis strains circulating in Mizoram.

METHODS

Sputum was cultured using MGIT 960 and DST was performed for Streptomycin, Isoniazid, Rifampicin, Ethambutol and Pyrazinamide. GeneXpert test was done simultaneously. DNA was extracted using Trueprep AUTO v2, molbio diagnostics. Antibiotic Resistance Genes and LSP were amplified and sequenced.

RESULTS

Ser315Thr was the most common mutation in katG among MDR-TB isolates. GeneXpert probes A and D drop out upon sequencing showed L511P, H526Q and H526L mutation. The L511P and H526Q mutations were seen in new and treated cases. Discrepancy between MGIT 960 and GeneXpert were observed. LSP-PCR revealed that Indo-Oceanic, East-African Indian, Euro-American and Beijing lineages were found in Mizoram.

CONCLUSION

This study provides mutation information on the resistant genotypes detected with GeneXpert as well as MGIT 960. It also provides information on the lineages of Mycobacterium tuberculosis circulating in the state. Utilization of sequencing technologies is essential in diagnostic laboratories to rule out discrepant results and as a cautionary measure to prevent wrong diagnosis and treatment.

The potential risk of international spread of Mycobacterium bovis associated with movement of alpacas

Introduction

The study highlights the transboundary nature of tuberculosis (TB) in alpacas and the failure of current ante-mortem testing protocols (the tuberculin skin and Enferplex Camelid TB tests) to identify TB-free alpaca herds and individuals for export. Our research and the available literature indicate that the alpaca (Vicugna pacos) is extremely susceptible to Mycobacterium bovis infection, and that testing periodicity fails to take into account that animals do not manifest disease symptoms for a long time. The skin test failed to identify Mycobacterium bovis infection in two alpacas prior to their movement from the UK to Poland. The animals were purchased by a breeding centre in Poland, and were then shown at an international animal exhibition. The last owner of the alpacas before their deaths from TB bought the infected animals unwittingly in order to run rehabilitation activities with disabled children on his farm.

Material and Methods

Thoracic lymph node, lung and liver tissue samples obtained at necropsy were examined histopathologically after Ziehl–Neelsen staining. Tissue samples were homogenised and mycobacteria present there were cultured on Stonebrink’s medium during a 6-week incubation. A commercial test using polymorphism of the chromosomal direct repeat region provided species identification and additional identification was by spacer oligonucleotide typing and mycobacteria interspersed repetitive unit–variable number tandem repeat analysis with a gel electrophoresis protocol.

Results

The microbiological examination confirmed multiorgan TB caused by the SB0666 spoligotype of Mycobacterium bovis.

Conclusion

Due to the suboptimal performance of current diagnostic tests for TB in alpacas, there is a risk that infected animals may be moved unwittingly. A risk of TB spread associated with the international movement of alpacas is implied by this study.

Geographically dispersed zoonotic tuberculosis in pre-contact South American human populations

Previous ancient DNA research has shown that Mycobacterium pinnipedii, which today causes tuberculosis (TB) primarily in pinnipeds, infected human populations living in the coastal areas of Peru prior to European colonization. Skeletal evidence indicates the presence of TB in several pre-colonial South and North American populations with minimal access to marine resources— a scenario incompatible with TB transmission directly from infected pinnipeds or their tissues. In this study, we investigate the causative agent of TB in ten pre-colonial, non-coastal individuals from South America. We reconstruct M. pinnipedii genomes (10- to 15-fold mean coverage) from three contemporaneous individuals from inland Peru and Colombia, demonstrating the widespread dissemination of M. pinnipedii beyond the coast, either through human-to-human and/or animal-mediated routes. Overall, our study suggests that TB transmission in the pre-colonial era Americas involved a more complex transmission pathway than simple pinniped-to-human transfer.

Mycobacterium tuberculosis infection in a free-ranging urban dog from Argentina

Mycobacterium bovis and Mycobacterium avium are the most important Mycobacteria isolated from diseased dogs, but Mycobacterium tuberculosis can be isolated as well, especially when close contact with humans exists. Free ranging street dogs may carry zoonotic diseases, being a potential health risk to new owners after adoption. In this study, the clinical case of a dog affected by Mycobacterium tuberculosis is described. A six-year-old bitch that had been living with a homeless man was rescued and put for adoption in dog shelter. After being adopted, her health declined, and abdominal ultrasound and exploratory laparoscopy were performed. A tuberculosis-like lesion in the liver was biopsied and histopathological, bacteriological, and molecular analyses were carried out. Then, the animal was euthanized and necropsied, and disseminated macroscopic tuberculosis-like lesions were observed in abdominal organs. Mycobacterium presence was confirmed by histopathological and bacteriological methods. Genotyping identified a SIT-1228 Mycobacterium tuberculosis strain. Notification to the sanitary authorities was performed and the couple that had contact with the dog were alerted and sent to the hospital for assessment, as Mycobacterium tuberculosis is a primary pathogenic agent for humans. The epidemiology in this clinical case is unclear, but the most likely source of infection might have been consumption of sputum contaminated food during the years that this bitch lived with the homeless man, because this person had died with chronic respiratory symptoms. Veterinarians must consider this disease and perform a complete diagnosis when dogs that used to live on the streets show nonspecific clinical signs.

Ocular Tuberculosis: More than 'Of Mice and Men'

Tuberculosis (TB), caused by infection with members of the Mycobacterium tuberculosis-complex, is one of the oldest known infectious disease entities, resulting in the death of millions of humans each year. It also results in a substantial degree of morbidity and mortality in animal species. Extrapulmonary TB is well recognized in humans, and the eye is one site that can be affected. Studies seeking to understand ocular TB have often relied on animal models; however, these have their limitations and may not truly reflect what happens in humans. We wish to raise awareness among ophthalmologists and vision scientists of naturally occurring cases of ocular TB in animals, namely cattle and domestic cats, and the possibilities of gaining further understanding of this presentation of TB by adopting a collaborative approach. This will hopefully improve outcomes for both human and animal patients.

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) vs. late (20 weeks) aerosol infection with M. bovis revealed 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) co-regulated 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.

Intradermal comparative cervical tuberculin test in the diagnosis of caprine tuberculosis

Tuberculosis remains one of the most important infectious diseases with well-known zoonotic nature that affect humans, wildlife, and domestic animals, including goats. Nonetheless, no intradermal tuberculin test has been standardized for caprine diagnosis of tuberculosis. The present study investigated the intradermal comparative cervical tuberculin test (ICCTT) in the diagnosis of tuberculosis among 60 goats from farms with history of tuberculosis. The cutoff applied to goats was based on a study where goats had been experimentally infected with Mycobacterium bovis and Mycobacterium avium. Clinical examination, bacteriological culture, and histopathological staining were assessed to the diagnosis. Isolates compatible with mycobacteria were subjected for molecular diagnosis based on gyrB-restriction fragment length polymorphism (RFLP) analysis and PCR restriction-enzyme analysis (PRA) of hsp65 gene by BstEII and HaeIII, namely PRA-hsp65 assay. From all goats, 60% (n = 36/60), 3.3% (n = 2/60), and 36.7% (n = 22/60) showed positive, inconclusive, and negative reactions, respectively. Out of 36 goats with ICCTT positive, 75% (n = 27/36) had isolation of mycobacteria and were detected M. bovis by gyrB-RFLP. Molecular diagnosis and histopathological findings compatible with tuberculosis showed 86.1% (n = 31/36) concordance with the ICCTT. When compared ICCTT with M. bovis isolation, gyrB-RFLP, and histopathology, the better arithmetic means of sensitivity and specificity were 2.5 mm for ICCTT compared with M. bovis isolation and gyrB-RFLP, and 4.55 mm when compared with histopathology. Both receiver operating characteristic (ROC) curves presented statistical significance (P < 0.001). The identification of other mycobacteria, e.g., M. kansasii, M. flavescens, M. avium, M. florentinum, M. lentiflavum, M. simiae, and Corynebacterium pseudotuberculosis, not influenced positive results in ICCTT. The concordance between bacteriological, histopathological, and molecular identification with ICCTT findings indicate that the tuberculin test may be used as a valuable tool for diagnosis of caprine tuberculosis and reinforce the importance of association of methods to diagnostic of the disease from animal origin.

Prevalence of bovine tuberculosis and distribution of tuberculous lesions in cattle slaughtered at Gondar, Northwest Ethiopia

Background

In Ethiopia, bovine tuberculosis (BTB) is a neglected disease that affects the economy and livelihoods of farmers. However, the available data is limited due to insufficient disease surveillance in the country. Therefore; this study aimed to assess the prevalence and distribution of lesions of BTB in cattle slaughtered at Gondar, Northwest Ethiopia.

Methods

Postmortem examinations were used to detect tuberculous lesions, while smear microscopy and histopathology were performed for the identification of acid-fast bacilli (AFB).

Results

Of 497 inspected slaughtered cattle, 45 (9.1%, 95%CI; 0.0668–0.1193) were diagnosed with BTB suggestive tuberculous lesions. A higher proportion of gross lesions was recorded in lymph nodes of lungs; at the mediastinal (14, 31.1%) and bronchial (10, 22.2%) lymph nodes, and followed by mesenteric lymph nodes (9, 20%). Of 45 tuberculous lesions; only 2 (4.4%) were identified as AFB positive by smear microscopy and histopathology. In the overall statistical analysis, body conditions of slaughtered cattle were found to be significantly associated with BTB tuberculous lesions (p < 0.05).

Conclusion

This finding provides the prevalence of BTB and distribution of tuberculous lesions in cattle slaughtered at the abattoir and highlights the need for a practicable control strategy of the disease in the region.

Mycobacterium bovis induces mitophagy to suppress host xenophagy for its intracellular survival

Mitophagy is a selective autophagy mechanism for eliminating damaged mitochondria and plays a crucial role in the immune evasion of some viruses and bacteria. Here, we report that Mycobacterium bovis (M. bovis) utilizes host mitophagy to suppress host xenophagy to enhance its intracellular survival. M. bovis is the causative agent of animal tuberculosis and human tuberculosis. In the current study, we show that M. bovis induces mitophagy in macrophages, and the induction of mitophagy is impaired by PINK1 knockdown, indicating the PINK1-PRKN/Parkin pathway is involved in the mitophagy induced by M. bovis. Moreover, the survival of M. bovis in macrophages and the lung bacterial burden of mice are restricted by the inhibition of mitophagy and are enhanced by the induction of mitophagy. Confocal microscopy analysis reveals that induction of mitophagy suppresses host xenophagy by competitive utilization of p-TBK1. Overall, our results suggest that induction of mitophagy enhances M. bovis growth while inhibition of mitophagy improves growth restriction. The findings provide a new insight for understanding the intracellular survival mechanism of M. bovis in the host.

Abbreviations: BMDM: mouse bone marrow-derived macrophage; BNIP3: BCL2/adenovirus E1B interacting protein 3; BNIP3L/NIX: BCL2/adenovirus E1B interacting protein 3-like; BCL2L13: BCL2-like 13 (apoptosis facilitator); CCCP: carbonyl cyanide m-cholorophenyl hydrazone; FUNDC1: FUN14 domain-containing 1; FKBP8: FKBP506 binding protein 8; HCV: hepatitis C virus; HBV: hepatitis B virus; IFN: interferon; L. monocytogenes: Listeria monocytogenes; M. bovis: Mycobacterium bovis; Mtb: Mycobacterium tuberculosis; Mdivi-1: mitochondrial division inhibitor 1; PINK1: PTEN-induced putative kinase 1; TBK1: TANK-binding kinase 1; TUFM: Tu translation elongation factor, mitochondrial; TEM: transmission electron microscopy

Effect of the Inoculation Site of Bovine and Avian Purified Protein Derivatives (PPDs) on the Performance of the Intradermal Tuberculin Test in Goats From Tuberculosis-Free and Infected Herds

The single and comparative intradermal tuberculin (SIT and CIT) tests are used for the ante-mortem diagnosis of caprine tuberculosis (TB). The tuberculin injection site has been associated with a different performance of the test in cattle. In contrast to that required in cattle in Europe (cervical injection), it can be carried out in the scapular region in goats. Nevertheless, there are no previous data concerning the effect of the injection site on the performance of the test in goats. The aim of the present study was to evaluate the effect of two different inoculation sites (cervical and scapular) on the performance of the SIT/CIT tests. This was done by intradermally inoculating 309 goats from two infected herds and one TB-free herd with both avian and bovine PPDs in the mid-cervical and scapular regions. None of the animals from the TB-free herd had positive reactions, and the number of reactors was not significantly higher, regardless of the inoculation site, in the high and low prevalence herds. However, significantly higher increases in skin fold thickness were observed on the cervical site when compared to the scapular site after the avian and bovine PPD inoculations in the TB-free herd (p < 0.001) and after the bovine PPD injection in the high prevalence herd (p = 0.003). The presence of clinical signs was also more evident on the cervical site when using avian and bovine PPDs in the high prevalence herd (p < 0.01). In contrast, increases in higher skin fold thickness were observed on the scapular site when compared to the cervical site after the bovine and avian PPD inoculations were employed in the low prevalence herd (p < 0.01). These results suggest that the cervical injection of PPDs may improve the sensitivity of the intradermal tuberculin test in high TB prevalence caprine herds, mainly owing to the increased presence of local clinical signs and a better performance of the CIT test. Moreover, specificity was not affected when using standard interpretations, although further analyses in a great number of herds are required in order to confirm these findings.

Tuberculosis patients at the human-animal interface: Potential zooanthroponotic and zoonotic transmission

Background

Human-to-animal transmission of M. tuberculosis (Mtb) is reported in South Africa but there is a paucity of epidemiological data. The aim of this One Health manuscript is to describe zooanthroponotic exposure of domestic animals to TB patients, virtually all of whom had laboratory confirmed pulmonary Mtb disease.

Methods

This cross-sectional study was nested within two TB contact tracing studies and collected data from 2017 to 2019. TB index patients and their households in three provinces of South Africa were recruited. A questionnaire was administered to households, assessing type and number of animals owned, degree of exposure of animals to humans, and veterinary consultations. For this analysis, we compared descriptive variables by animal-keeping status (animal-keeping vs non-animal keeping households), calculated the chi square and respective p-values.

Results

We visited 1766 households with at least one confirmed case of TB, 33% (587/1766) had livestock or companion animals. Of non-animal-owning households, 2% (27/1161) cared for other community members' livestock. Few (16%, 92/587) households kept animals in their dwelling overnight, while 45% (266/587) kept animals outside the home, but within 10 m of where people slept and ate. Most (81%, 478/587) of people in animal-owning households were willing for their animal/s to have a TB skin test, but <1% (5/587) of animals had been skin-tested; 4% (24/587) of animal-owning households had a veterinary consultation in the past six months, and 5% (31/587) reported one of their animals dying from natural causes in the prior six months.

Conclusion

Our survey suggests that a high proportion of patients with TB live in settings facilitating close contact with domestic animal species with known susceptibility to Mtb. There is a substantial exposure of household animals to patients with TB and therefore risk of both transmission to, and spillback from animals to humans.

A multiplex assay for the detection of antibodies to relevant swine pathogens in serum

Livestock industry supports the livelihood of around 1.3 billion people in the world, with swine industry contributing with 30% of total livestock production worldwide. To maintain and guarantee this production, a pivotal point according to the OIE is addressing potential biohazards. To control them, permanent sero-surveillance is crucial to achieve more focused veterinary public health intervention and prevention strategies, to break the chains of transmission, and to enable fast responses against outbreaks. Within this context, multiplex assays are powerful tools with the potential to simplify surveillance programs, since they reduce time, labour, and variability within analysis. In the present work, we developed a multiplex bead-based assay for the detection of specific antibodies to six relevant pathogens affecting swine: ASFV, CSFV, PRRSV, SIV, TB and HEV. The most immunogenic target antigen of each pathogen was selected as the target protein to coat different microsphere regions in order to develop this multiplex assay. A total of 1544 serum samples from experimental infections as well as field samples were included in the analysis. The 6-plex assay exhibited credible diagnostic parameters with sensitivities ranging from 87.0% to 97.5% and specificities ranging from 87.9% to 100.0%, demonstrating it to be a potential high throughput tool for surveillance of infectious diseases in swine.

Mycobacterium tuberculosis SIT42 Infection in an Abused Dog in Southern Italy

A case of Mycobacterium tuberculosis infection is described in a dead adult male dog in Southern Italy. The carcass was found by the Health Authority in a gypsy encampment. It was admitted to our forensic veterinary medicine unit, with a suspicion of cruelty to the animal. Necropsy showed beating and traumatism signs, and mistreating was confirmed. Gross lesions included multiple nodular hepatic lesions, hemorrhagic enteritis with enlarged mesenteric lymph nodes, body cavity effusions, and an adrenal neoplasm. Bacteriological and molecular analyses were carried out on the liver lesions that enabled to identify M. tuberculosis SIT42 (LAM9). Drug-resistance patterns were evaluated by screening mutations on the rpoB and katG genes that showed susceptibility to both rifampin and isoniazid, respectively. Very few studies report canine tuberculosis, and little is known about the disease in Italy. To the authors' knowledge, this is the first report of Mycobacterium tuberculosis SIT42 infection in a dog in Italy.

The effectiveness of bovine tuberculosis surveillance in Dutch badgers

Countries survey wildlife for bovine tuberculosis (bTB) to ensure case detection or to ascertain a high probability of freedom from bTB in wildlife. The Eurasian badger (Meles meles) is a potential bTB reservoir host. Between 2008 and 2019, 282 badgers were examined post‐mortem in the context of general wildlife disease and targeted bTB surveillance programmes in the Netherlands, and no bTB cases were detected. However, it was unclear how effective this surveillance effort was to demonstrate freedom from Mycobacterium bovis infection in the badger population of ±6000 or to detect cases if present.

Therefore, surveillance effectiveness was assessed using scenario tree modelling. For lack of standards for wildlife, the models were run against three assumed levels of disease in the population called design prevalence P*: 0.1%, 0.5%, and 3%. A small risk of introduction (0.015/year) was applied, because the Netherlands are officially free from bTB in cattle, with rare import of bTB‐infected cattle and no bTB‐infected wildlife reported along the Belgian and German borders with the Netherlands. Surveillance more readily picks up bTB presence in badgers when case detection sensitivity tends towards 100% and demonstrates freedom best when the probability of freedom tends towards 100%.

For P* 0.1%, 0.5% and 3%, respectively, maximum case detection sensitivity during 2008–2019 was 8%, 35% and 94% and the probability of freedom in 2019 was 46%, 67%, and 95%. At P* = 3%, performing targeted surveillance on 300 badgers in a year would make it extremely unlikely to miss a case (case detection sensitivity > 99.9%); and if no cases are detected, the adjusted probability of freedom would then reach nearly 98.5%. Stakeholders should be made aware that at P* = 3%, one case detected implies around 3% infected badgers. Additional surveillance system components to assess bTB in wildlife and its economics are to be explored further.

Retrospective analysis of the control and prevention of tuberculosis among cattle in Ukraine in the period 1994–2020

Bovine tuberculosis (bTB) – is a chronic infectious disease, the causative agent of which affects many species of mammals. It is a zoonosis caused by various types of mycobacteria in the complex Mycobacterium tuberculosis family Mycobacteriaceae. The most important etiological agent of bTB in cattle is M. bovis, which has been isolated from tuberculosis infected cattle for centuries. Livestock and species of the Bovidae family are the most susceptible to this pathogen and are the main reservoir species for animals and humans. In Ukraine, the main methods of diagnosing tuberculosis in animal husbandry are lifetime (clinical examination, allergic intradermal test with tuberculin), and postmortem techniques (pathological changes, bacteriological investigation). The authors performed a retrospective analysis of the epizootic situation of tuberculosis among cattle in Ukraine for the period 1994–2020 and conducted a critical assessment of the work done to prevent and control this disease. In total, over the last 27 years, 219 088 head of cattle with tuberculosis and 933 affected locations have been identified in Ukraine. The results of this work showed that in our country the epizootic situation of bovine tuberculosis on farms of various forms of ownership is fully controlled. The most active fight against tuberculosis was carried out during 1995–2015. In 1994–1997, the largest number of affected locations was registered, from 90 to 144, respectively, and the largest number of animals with tuberculosis – 21 395–33 474. In 1994–1995, the largest number of sick animals per one affected point was registered (371.9 and 471.7 head, respectively). Currently, official statistics show that many farms, especially in Vinnytska, Cherkaska and Kyivska regions, continue to show positive allergic reactions to tuberculin (46 898 reactions for the last 12 years). Applying diagnostic methods of research in complex (bacteriological, bioassay, molecular), excludes affection of cattle by pathogenic mycobacteria. This study showed that for the last 5 years no farms with confirmed pathological diagnosis by bacteriological methods have been registered and no culture of the pathogen from animals has been detected. Besides the scurpulous work of the veterinary service, in our opinion, the catastrophic decline in the number of cattle in Ukraine also had a significant impact on improving the epizootic situation regarding tuberculosis.

Real-Time PCR Validation for Mycobacterium tuberculosis Complex Detection Targeting IS6110 Directly From Bovine Lymph Nodes

Rapid and accurate diagnostic tools, such as Real-Time PCR (qPCR), need to be implemented as a confirmatory test in the framework of bovine tuberculosis (bTB) surveillance and control programs, shortening the turnaround time to confirm bTB infection. The present study aimed to evaluate a direct qPCR from fresh tissue samples targeting the insertion sequence IS6110 using individually homogenized bovine lymph nodes compared with microbiological culture. Retropharyngeal, tracheobronchial, and mesenteric lymph nodes fresh tissue samples (n = 687) were collected from 230 different cattle carcasses at the slaughterhouse. Only 23 of the 230 examined animals showed tuberculosis-like lesions, with 62 of 230 considered as positive. Among these 62 animals, 61 resulted as culture-positive, whereas 48 were qPCR-positive. Thus, this qPCR targeting IS6110 showed an apparent diagnostic sensitivity and specificity values of 77.1% [95% confidence interval (CI): 66.5–87.6%] and 99.4% (95% CI: 98.3–100.6%), respectively, and a positive predictive value of 97.9% (95% CI: 93.9–102.0%) and negative predictive value of 92.3% (95% CI: 88.4–96.2%). Positive and negative likelihood ratios were 130.2 and 0.2, respectively, and the agreement between microbiological culture and this qPCR was almost perfect (κ = 0.82). These results highlight this qPCR targeting IS6110 as a suitable complementary method to confirm bTB in animals with either tuberculosis-like lesions or non-tuberculosis-like lesions, decreasing the number of samples subjected to microbiological culture and, hence, its overall associated costs and the turnaround time (under 48 h) to confirm bTB infection. Besides, sampling mesenteric lymph node, which is uncommonly sampled, together with tracheobronchial and retropharyngeal ones, is advisable during postmortem inspection in bTB surveillance programs at the slaughterhouse, especially in areas with a low bTB prevalence scenario.

Apoptotic caspases suppress Mycobacterium bovis-induced IFN-β production in murine macrophage

Caspases are classified as inflammatory or apoptotic category. Inflammatory caspases participate in inflammasome activation, while apoptotic caspases mediate apoptotic activation. Previous studies have shown that apoptotic caspases prevent the production of IFN-β during apoptosis or virus infection. However, the relationship between apoptotic caspases and IFN-β production during intracellular bacterial infection is still unclear. Here, we investigated the role of apoptotic caspases in IFN-β production induced by Mycobacterium bovis (M. bovis) infection. M. bovis is an intracellular bacterium and belongs to the Mycobacterium tuberculosis complex. M. bovis infection can cause tuberculosis in animals and human beings. In the current study, we found that M. bovis infection triggered mitochondrial stress, which caused the leakage of cytochrome c into the cytoplasm, and in turn, activated the downstream caspase-9 and-3. Furthermore, our results showed that activation of apoptotic caspases reduced IFN-β production during M. bovis infection and vice versa. Confocal microscopy analysis revealed that apoptotic caspases prevented IFN-β production by decreasing p-IRF3 nuclear translocation. Our findings demonstrate that apoptotic caspases negatively regulate the production of IFN-β induced by an intracellular bacterial infection.

Spoligotype-specific risk of finding lesions in tissues from cattle infected by Mycobacterium bovis

Background

Although the pathogenic effect of members of the Mycobacterium tuberculosis complex in susceptible hosts is well known, differences in clinical signs and pathological findings observed in infected animals have been reported, likely due to a combination of host and pathogen-related factors. Here, we investigated whether Mycobacterium bovis strains belonging to different spoligotypes were associated with a higher risk of occurrence of visible/more severe lesions in target organs (lungs and/or lymph nodes) from infected animals. A large collection of 8889 samples belonging to cattle were classified depending on the presence/absence of tuberculosis-like lesions and its degree of severity. All samples were subjected to culture irrespective of the presence of lesions, and isolates retrieved were identified and subjected to spoligotyping. The association between the presence/severity of the lesions and the isolation of strains from a given spoligotype was assessed using non-parametric tests and Bayesian mixed multivariable logistic regression models that accounted for origin (region and herd) effects.

Results

Results suggested a difference in severity in lesioned samples depending on the strain’s spoligotype. An association between specific spoligotypes and presence of lesions was observed, with a higher risk of finding lesions in animals infected with strains with spoligotypes SB0120, SB0295 and SB1142 compared with SB0121, and in those coming from certain regions in Spain.

Conclusions

Our results suggest that strains belonging to certain spoligotypes may be associated with a higher probability in the occurrence of gross/macroscopic lesions in infected cattle, although these observational findings should be confirmed in further studies that allow accounting for the effect of other possible confounders not considered here, and ultimately through experimental studies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-021-02848-3.

The effects of intradermal M. bovis and M. avium PPD test on immune-related mRNA and miRNA in dermal oedema exudates of water buffaloes (Bubalus bubalis)

Tuberculosis (TB) is a zoonotic disease primarily caused by pathogens belonging to the genus of Mycobacterium. Programs of control and eradication for bovine TB include a screening using single intradermal tuberculin (SIT) test with Mycobacterium bovis (M. bovis)-purified protein derivatives (PPD-B) single or concurrent with Mycobacterium avium (M. avium)-purified protein derivatives (PPD-A). This study aimed to determine the effects of intradermal PPD-B and PPD-A test on immune-related mRNA and microRNAs in dermal oedema exudates of water buffaloes (Bubalus bubalis). The investigation was carried out on RNA extracted from dermal oedema exudates of 36 animals, of which 24 were M. bovis positive (M. bovis+) and 12 M. avium positive (M. avium+). The lymphocyte polarization toward Th1, Th2, TReg, and Th17 lineages was addressed by measuring the abundance of the respective cytokines and transcription factors, namely TBET, STAT4, IFNγ, and IL1β for Th1; STAT5B, and IL4 for Th2; FOXP3 and IL10 for TReg; and RORC, STAT3, and IL17A for Th17. Due to the very low abundance of Th17-related genes, a digital PCR protocol was also applied. The abundance of microRNAs involved in the immune response against PPDs, including miR-122-5p, miR-148a-3p, miR30a, and miR-455-5p, was equally measured. Results showed that IFNγ (fold change = 2.54; p = 0.037) and miR-148a-3p (fold change = 2.54; p = 0.03) were upregulated in M. bovis+ as compared to M. avium+ samples. Our preliminary results supported the pivotal role of IFNγ in the local immune response related to PPD-B and highlighted the differential expression of miR-148a-3p, which downregulates the proinflammatory cytokines and the TLR4-mediated NF-κB activation, providing an anti-inflammation modulator in responses to mycobacterial infection.

Intra-vitam Diagnosis of Tuberculosis in Pigs: Concordance Between Interferon-Gamma Release Assay and Comparative Tuberculin Skin Test

The role of pigs in the maintenance of bovine tuberculosis caused by Mycobacterium bovis has been demonstrated in many settings; however, the current control programs usually do not state any intra-vitam diagnostic procedure in this species, as for the cattle. Carcass inspection has shown to be insufficient to detect infection in swine; thus, the assessment of intradermal tuberculin test and interferon-gamma release assay (IGRA) in this species is mandatory. The current study compares the performances of the single intradermal comparative cervical tuberculin (SICCT) test and IGRA. A total of 628 Nebrodi Black pigs raised in free-roaming farms were subjected to the two tests simultaneously. Besides, 124 animals underwent postmortem examination for the detection of tuberculous lesions and isolation of mycobacteria from target organs. The two tests showed a concordance of 94.42% with a Cohen's k coefficient of 0.786 and McNemar chi-square of 4.83 (P = 0.03). Slightly lower levels of concordance (90.32%) between SICCT and IGRA were obtained in the group of 124 animals, with a Cohen's k = 0.797 and McNemar chi-squared value of 0.69 with a non-significant P = 0.41. Moreover, the results showed how IGRA tends to result positive in higher rates, mostly when non-tuberculous mycobacteria (NTM) were isolated, suggesting a possible impairment of specificity in the event of coinfections in the swine. In conclusion, the results obtained support the possibility of the strategic use of IGRA or SICCT in combination or alternatively one to the other, particularly IGRA which showed lower specificity but has evident advantages over SICCT.

Estimates of the global and continental burden of animal tuberculosis in key livestock species worldwide: A meta-analysis study

Zoonotic animal tuberculosis (TB) is a One Health paradigm infectious disease, caused by Mycobacterium tuberculosis complex bacteria, that affects different host species with varying levels of management. In most developed countries, official surveillance and control strategies support the longitudinal reporting of herd and/or animal prevalence. However, for under resourced countries without surveillance plans, this information may be obtained from cross-sectional studies only. The objective of this meta-analysis was to perform a worldwide estimate of the overall prevalence of animal TB in different livestock species whose importance in production systems varies according to the region of the world. The ISI's Web of Science and Google Scholar were searched combining keywords and related database-specific subject terms to identify relevant cohort or cross-sectional work published in this topic. A total of 443 articles were retrieved, screened, and a final set of 182 references included. Potential sources of variation were investigated using subgroup analyses and meta-regression. Prevalence estimates in five mammalian host groups were stratified according to host species, host characteristics, anatomical localization of lesions, sample size, geographical location, and diagnostic tests. The multivariable meta-regression analysis accounted for a range between 0% (farmed wild boar) and 68.71% (camelids) of the overall observed heterogeneity, indicating that the pondered predictors partially explain the observed variability. Differences in the overall prevalence of TB across hosts were small, with most groups showing values around 10%, except farmed wild boar (41%). The sample size emerged as an important moderator, with small size studies leading to the overestimation of prevalence. TB prevalence rates were very heterogeneous across continents and depended on the host, with lower values (below 10%) in Africa and Asia, while North America (33.6%, cattle), Europe (51%, goats), and South America (85.7%, pigs) exhibited higher rates, possibly related to greater densities of specific host groups managed on more intensive production systems. Stratification by diagnostic tests evidenced heterogeneous prevalence rates depending on the host group, possibly reflecting differences in test performance across different hosts. Results from this study highlight different TB burden scenarios, pinpointing host groups and diagnostics that should be prioritized in surveillance systems in different regions, thus providing policy-relevant information to catalyse TB control in settings with lower installed capacity and better resource allocation at the human-animal-environment interface.

Bacteriological, cytological, and molecular investigation of Corynebacterium pseudotuberculosis, mycobacteria, and other bacteria in caseous lymphadenitis and healthy lymph nodes of slaughtered sheep

Caseous lymphadenitis (CL) in sheep is a chronic contagious disease caused by Corynebacterium pseudotuberculosis, commonly characterized by abscess formation in peripheral lymph nodes and disseminated infections. Nonetheless, other microorganisms, including with zoonotic relevance, can be isolated from CL-resembling lymph nodes. Currently, mycobacteria have been reported in visceral granulomatous lesions in small ruminants, a fact that poses a public health issue, particularly in slaughtered sheep intended for human consumption. Cytology using fine needle aspiration and microbiological culturing are suitable tests for routine diagnostic, whereas present drawbacks and molecular methods have been confirmatory. Data about the occurrence of mycobacteria in both lymph nodes with aspect of CL and apparently healthy visceral nodes of sheep slaughtered for human consumption are scarce. In this study, 197 visceral lymph nodes of sheep showed lymphadenitis and 202 healthy visceral lymph nodes of slaughtered sheep intended for human consumption were submitted to conventional bacteriological diagnosis, mycobacteria culturing, and cytological evaluation. Compatible Corynebacterium isolates were subjected to multiplex PCR targeting 16S rRNA, rpoB, and pld genes to detect C. pseudotuberculosis. Based on microbiological identification, C. pseudotuberculosis (86/197; 43.7%), streptococci γ-hemolytic (17/197; 8.6%), and Trueperella pyogenes (12/197; 6.1%) were prevalent in lymph nodes with abscesses, as opposed to staphylococci (53/202; 26.2%) in apparently healthy lymph nodes. No mycobacteria were isolated. Cytology identified 49.2% (97/197) Gram-positive pleomorphic organisms (coryneform aspect). Multiplex PCR confirmed genetic material of C. pseudotuberculosis in 74.4% (64/86) of the samples with C. pseudotuberculosis isolation and 66% (64/97) samples with cytological coryneform aspect (κ = 86.78%; 95% CI = 79.87-93.68%). These findings emphasize the prevalence of C. pseudotuberculosis in abscess formation among peripheral lymph nodes of sheep. Other bacteria were also identified in lymph nodes sampled that resembling C. pseudotuberculosis-induced infections that may difficult the diagnosis. Multiplex PCR revealed a valuable assay to detect C. pseudotuberculosis, in addition to routine methods applied to CL-diagnosis. No mycobacteria were identified in lymph nodes sampled, with and without apparent lesions. Nonetheless, due to public health impacts, this pathogen should be considered as a differential diagnosis of C. pseudotuberculosis-induced infections during inspection procedures of slaughtered sheep intended for human consumption.

Tuberculosis caused by Mycobacterium caprae in a camel (Camelus dromedarius)

BACKGROUND

Animal tuberculosis (TB) is distributed worldwide and has a wide range of wild and domestic reservoirs. Few studies concerning TB in camelids have been published in the last decade, particularly as regards Old World Camelids (OWC), but the increase in reports of TB outbreaks in these species in recent years suggests a high susceptibility to the infection.

CASE PRESENTATION

We studied a dromedary camel (Camelus dromedarius) herd (n = 24) in which a Mycobacterium caprae infection was detected. The TB infection was confirmed in one animal at necropsy through the detection of TB lesions, mainly in the abdominal organs, and the subsequent isolation of M. caprae (SB0157 spoligotype). The whole herd was additionally tested using cellular and humoral based diagnostic techniques. The intradermal tuberculin test results were compared with those obtained using P22 ELISA for the detection of specific antibodies against the M. tuberculosis complex. The TB infected animal was a positive reactor to both the intradermal tuberculin tests and P22 ELISA, while the others were negative to all the diagnostic tests.

CONCLUSION

The present study found M. caprae infection in OWC. This is the first report of M. caprae infection in an OWC not living in a zoo. Since the animal was born in the herd and fed with goat's milk, this practice was suspected to be the potential source of TB infection, which was not confirmed in the other animals present in the herd. Moreover, our results highlight that the intradermal tuberculin test and the P22 ELISA could be valuable tools for the diagnosis of TB in OWC.

Feline tuberculosis caused by Mycobacterium bovis infection of domestic UK cats associated with feeding a commercial raw food diet

Mycobacterium (M.) bovis can infect cats and is a demonstrated zoonosis. We describe an outbreak of M. bovis in pet cats across England and Scotland associated with feeding a commercial raw food diet. Forty-seven cats presented with (pyo)granulomatous lesions, lymphadenopathy, pulmonary and/or alimentary disease over a one-year period where M. bovis infection was suspected or definitively diagnosed, and the cats all consumed the same specific brand of commercial raw venison pet food. Infection with M. bovis genotype 10:a was confirmed by culture and DNA typing of isolates in a small number of cases (n = 5); PCR was used in combination with or as an alternative to culture (n = 12) and/or infection with a Mycobacterium tuberculosis complex group organism was strongly suggested by positive responses to an interferon-gamma release assay (IGRA; n = 34). Asymptomatic at-risk cats were screened by IGRA, identifying a further 83 infected cats. The five culture-positive cases were distributed across areas of England and Scotland at low risk of endemic bovine tuberculosis. Investigations revealed affected cats were mainly indoor-only, and had been fed the same commercial raw food as at least part of their diet. This diet was recalled by the manufacturer due to failure of statutory meat inspection of the component venison. As far as possible, other sources of infection were explored and excluded, including wildlife contact, access to raw milk and living with people with active M. bovis infection. Four owners and one veterinary surgeon were found to have high likelihood of latent tuberculosis infection. One owner required treatment. Although it was not possible to conclusively demonstrate a zoonotic origin for these infections, neither was it possible to eliminate the possibility. Our results provide compelling evidence that the commercial raw diet of these cats was the likely route of M. bovis infection in this outbreak of cases.

Epidemiology of Tuberculosis in Multi-Host Wildlife Systems: Implications for Black (Diceros bicornis) and White (Ceratotherium simum) Rhinoceros

Cases of tuberculosis (TB) resulting from infection with Mycobacterium tuberculosis complex (MTBC) have been recorded in captive white (Ceratotherium simum) and black (Diceros bicornis) rhinoceros. More recently, cases have been documented in free-ranging populations of both species in bovine tuberculosis (bTB) endemic areas of South Africa. There is limited information on risk factors and transmission patterns for MTBC infections in African rhinoceros, however, extrapolation from literature on MTBC infections in other species and multi-host systems provides a foundation for understanding TB epidemiology in rhinoceros species. Current diagnostic tests include blood-based immunoassays but distinguishing between subclinical and active infections remains challenging due to the lack of diagnostic techniques. In other species, demographic risk factors for MTBC infection include sex and age, where males and adults are generally at higher risk than females and younger individuals. Limited available historical information reflects similar age- and sex-associated patterns for TB in captive black and white rhinoceros, with more reports of MTBC-associated disease in black rhinoceros than in white rhinoceros. The degree of MTBC exposure in susceptible wildlife depends on their level of interaction, either directly with other infected individuals or indirectly through MTBC contaminated environments, which is dependent on the presence and abundance of infected reservoir hosts and the amount of MTBC shed in their excreta. Captive African rhinoceros have shown evidence of MTBC shedding, and although infection levels are low in free-ranging rhinoceros, there is a risk for intraspecies transmission. Free-ranging rhinoceros in bTB endemic areas may be exposed to MTBC from other infected host species, such as the African buffalo (Syncerus caffer) and greater kudu (Tragelaphus strepsiceros), through shared environmental niches, and resource co-utilization. This review describes current knowledge and information gaps regarding the epidemiology of TB in African rhinoceros.

Tuberculosis in small ruminants and dromedary camels in Ethiopia: A systematic review and meta-analysis

Tuberculosis (TB) is a chronic infectious disease of livestock with serious economic and public health impact in Ethiopia. The disease is reported from cattle, small ruminants and dromedary camels in the country. However, there is no organized summary report on the magnitude and distribution pattern of TB in small ruminants and dromedary camels, unlike that of bovine TB. Consequent to this gap, this review was organized to provide pooled prevalence estimates, and examine level of heterogeneity among studies at national level. In addition, it attempts to illustrate the spatial distribution patterns along the three livestock species based on available reports. Tuberculosis articles on the aforesaid livestock species were searched online using PubMed, CAB direct, Web of Science and AJOL databases. Eighteen articles published from January 2000 to May 15, 2020, written in the English language that fulfill the selection quality criteria were considered for the review. Altogether, 50 district based observational studies conducted on 10,371 goats, 6262 dromedary camels, and 1457 sheep were used for analysis. Accordingly, the pooled prevalence estimates of TB, in a random effect model were 2.3 % (95 % CI: 1.7, 3.1) for goats, 0.8 % (95 % CI: 0.5, 1.4) for sheep and 8.2 % (95 % CI: 6.6, 10.2) for dromedary camels. The subgroup analysis revealed presence of statistically significant differences (p < 0.001) in pooled prevalence estimates among the three species. In multivariable meta-regression model, diagnostic methods used for screening (single intra-dermal comparative cervical tuberculin test (SICCTT)> 2mm, SICCTT > 4mm and detailed postmortem inspection) were the only predictors identified to show statistically significant difference (p<0.001) and explained 68.6 % of the explainable heterogeneity (R² =0.686) in goat TB studies. In general, study reports on small ruminant and dromedary camel TB are limited throughout the country. The most significant data gaps were in Gambella, and Benshangul-Gumuz regional states, where no single report could be retrieved on small ruminant TB. Limitation of study reports and lack of comparable categories constrained further investigation on other predictors in sheep and camel studies. Thus, the authors would like to emphasize the need for more representative studies in the species of concern in all regions of the country. Meanwhile, the relatively higher proportion of TB in dromedary camels demands special attention in arid and semiarid parts of the country, as it is the leading livestock species on which agropastoralist and pastoralists livelihoods depend.

Identification of B cell antigenome in Mycobacterium bovis by immunoproteomic analysis

Bovine tuberculosis (bTB) is a common zoonosis prevalent in many countries with grave economic consequences. Most developed and developing countries have implemented the test-and-slaughter policy to protect public health and reduce economic losses in the cattle industry. The official diagnosis of bTB is based on assays dependent on cell-mediated immunity (CMI). CMI-based diagnosis demonstrates diagnostic incapability at late stages of infection, which could be overcome by diagnosis based on humoral immunity (HI). Therefore, there is an urgent need to identify and define the B cell antigenome of Mycobacterium bovis. In this study, the B cell antigenome of culture filtrate proteins (CFP) was defined by mass spectrometry-based proteomics technology. Four spots were detected on 2-dimensional gel electrophoresis (2-DE) against M. bovis-positive serum in an immunoblotting experiment. Twenty-one proteins were identified in four spots by proteomic tools, such as Mb2900, Mb2898, Mb0448, Mb3834c, Mb1918c, Mb0134c, Mb0358 and Mb1868c, which are known B cell antigens, including 13 new proteins, i.e. Mb3751, Mb2006c, Mb3276c, Mb2244, Mb1164c, Mb2553c, Mb2946c, Mb1849c, Mb1511c, Mb1034c, Mb2616c, Mb0854c and Mb2267. These new proteins identified by 2-DE and immunoblotting were the B cell antigens used in developing serological diagnostic methods based on HI to bTB.

Review on Epidemiology and Public Health Importance of Goat Tuberculosis in Ethiopia

Small ruminant is an important and integral part of livestock in Ethiopia. Especially, goats are attractive to people of Ethiopia because of the ability to resist challenges, easily adapt to different ecological regions, and need small land to rearing and small initial capital in which poor people can engaged in the production system. In spite of the presence of large number of goat population in Ethiopia, it fails to utilize expected productivity due to many factors. Among the factors, which limit the economic returns of goats, diseases stand frontline. Tuberculosis is one the diseases that affect goats' health and production in Ethiopia. Goat tuberculosis is a chronic disease, which is characterized by the development of granulomas, essentially in the respiratory tract and related lymph nodes, from which the mycobacteria are discharged and contaminate other susceptible animals. Goat tuberculosis has a public health implication in Ethiopia because of the farmers' habit of consuming raw goat milk and its products, and they do have consistent or day-to-day contact with their goats. The etiological agents also transmitted to humans through the aerogenous route from those animals with active cases in the herd. The infection has been reported from several parts of different areas of the country dependent on the abattoir inspections. Therefore, attention should be given towards the control of tuberculosis in livestock; public health education on zoonotic importance of the disease or awareness creation and the national tuberculosis control needs to consider the one health approach, and further epidemiological studies should be undertaken.