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Tuberculin skin tests (TST), the primary diagnostic tool for bovine tuberculosis (bTB), cross-react with BCG vaccine. Recently developed defined antigen skin tests (DSTs) aim to differentiate infected amongst vaccinated animals. We evaluated the field performance of different interpretations of the TST and DSTs relative to IGRA and IDEXX M. bovis antibody tests. This panel of tests was assessed in 446 unvaccinated cattle across 22 Ethiopian dairy herds using Bayesian latent class models. We extended the standard Walter-Hui model to include age-related effects to explore evidence of the presence of diagnostic anergy. The latent class models estimate sensitivity and specificity of the DSTs to be between 84–88% and 79–85% respectively. The DSTs perform intermediately between the comparative intradermal test (CIT, sensitivity 77%, specificity 100%) and single intradermal test (SIT, sensitivity 99%, specificity 76%). We observed significant age-related declines in test sensitivity, most notably for CIT (declining from 75 to 52% over 9 years) and DST10 (83% to 68%), while other tests showed more stable sensitivity across age groups. This variable pattern across tests suggests mechanisms beyond simple age-related anergy. Together, these findings demonstrate that DSTs’ superior sensitivity to CIT and comparable or better specificity than SIT, combined with their ability to distinguish vaccinated animals, creates a viable pathway for implementing BCG vaccination programs. Given the absence of any gold standard definition of infection with bTB, latent class analyses are essential to assess the relative performance of different diagnostic tests. While our results provide encouraging news for the sensitivity of the new DST tests, the high prevalence of bTB within our study population makes our design underpowered to assess the specificity of the DSTs. Future research, including assessment of the specificity of DSTs in disease-free populations and optimization of test formulation and validation through large-scale field trials is essential to fully establish the case for use in vaccination and surveillance programs.

Background Bovine tuberculosis (bTB) is a chronic disease caused by members of the Mycobacterium tuberculosis complex (MTBC) that ultimately leads to the development of progressive granulomatous lesions. Although the disease is widespread, especially in crossbred cattle in Ethiopia, routine investigations and surveillance are lacking. Thus, the aim of this study was to determine the prevalence, associated risk factors, and species of mycobacteria causing bTB in slaughtered cattle at four slaughterhouses in Central Ethiopia. Methods Postmortem examination of 7,640 cattle was conducted using a cross-sectional slaughterhouse survey. A total of 388 tuberculous-like lesions (TBLs) were collected from 173 animals and cultured. Six target genes were used to differentiate mycobacterial species using multiplex real-time PCR (mRT-PCR). Multivariate logistic regression analyses and related odds ratios (ORs) were used to gauge the strength of the associations between risk factors, TBL incidence and culture growth. Results The prevalence of TBL was 2.3% (95% CI = 2.0-2.6). Logistic regression analysis indicated an increased risk of TBL in crossbred cattle (OR = 11.8, 95% CI: 6.4, 21.2, p  < 0.001). Animals slaughtered at Adama (OR = 3.2, 95% CI: 1.2, 7.3, p  = 0.009) or Burayu (OR = 5.8, 95% CI: 3.9, 8.9, p  < 0.001) had a greater risk of TBL than those slaughtered at Sululta. There were significantly more TBL-positive lesions in the lungs and lymph nodes related to the lung (OR = 7.1; 95% CI: 2.7, 24.5, p  < 0.001) and the head lymph node (OR = 5.6; 95% CI: 1.8, 21.7; p  = 0.006) compared to gut associated lymph nodes. Among the 173 TBL-positive animals, 36% (95% CI = 28.8, 43.2), and among the 388 TBL-positive tissues, 24.2% (95% CI = 20, 29) were culture and mRT-PCR positive. All the culture-generated isolates were positive for M. bovis in mRT-PCR. Among them, two animals had mixed infections including one zebu cattle tested positive for both M. caprae and M. bovis , and a crossbred cow tested positive for both M. tuberculosis and M. bovis in mRT-PCR. This suggests persistent transmission within the cattle population, posing a substantial public health threat. Conclusion This study revealed an eleven-fold greater risk of bTB-related lesions in crossbred cattle compared to local zebu cattle. This finding highlights the necessity for targeted interventions, continuous vigilance, and thorough carcass inspection to mitigate public health risks.

Bovine tuberculosis (bTB) is endemic and has a substantial impact on the livestock sector in Ethiopia and other low and middle-income countries (LMICs). With a national emphasis on dairy farm intensification to boost milk production and spur economic growth, the incidence of bTB is anticipated to rise. However, Ethiopia, like other LMICs, lacks a comprehensive national bTB control strategy due to the economic and social infeasibility of traditional test-and-cull (TC) approaches. To inform the development of such a strategy, we evaluated the effectiveness and feasibility of TC and test-and-segregation (TSg) strategies for bTB control on Ethiopian dairy farms. A TC approach was used at Farm A [N = 62; comparative cervical test (CCT) > 4 mm, starting prevalence 11.3%] while TSg was implemented at Farm B (N = 45; CCT > 4 mm, prevalence 22.2%), with testing intervals of 2–4 months. Both strategies achieved a reduction in bTB prevalence to 0%, requiring seven rounds of TC over 18 months at Farm A, and five rounds of TSg over 12 months at Farm B’s negative herd. The results show that adopting more sensitive thresholds [CCT > 0 mm or single cervical test (SCT) > 2 mm] during later rounds was pivotal in identifying and managing previously undetected infections, emphasizing the critical need for optimized diagnostic thresholds. Cost analysis revealed that TC was approximately twice as expensive as TSg, primarily due to testing, labor, and cow losses in TC, versus construction of new facilities and additional labor for TSg. This underscores the economic and logistical challenges of bTB management in resource-limited settings. Taken together, our study highlights an urgent need for the exploration of alternative approaches including TSg and or vaccination to mitigate within herd transmission and enable implementation of bTB control in regions where TC is not feasible.

Bovine tuberculosis (bTB) is a threat to cattle health and public safety. The current control programs are hampered by wildlife reservoirs and socioeconomic barriers. Vaccinating cattle with Bacillus Calmette-Guérin (BCG) effectively reduces transmission, offering a potential solution for controlling bTB. A key requirement for vaccination strategies using BCG is the validation of defined antigens to differentiate infections among vaccinated animals (DIVA). We compared tuberculin with DIVA peptide cocktails (ESAT-6, CFP-10, and Rv3615c) in 67 unvaccinated and 67 BCG-vaccinated cattle exposed to M. bovis in a natural setting. The cattle were tested every 4 months with a skin test and every 2 months with interferon-gamma (IFN-γ) release assays (IGRA) over a year of exposure. Before exposure, the DIVA skin, DIVA IGRA, and tuberculin tests showed 100% specificity in unvaccinated control calves. After exposure, the DIVA skin, DIVA IGRA, and comparative cervical tuberculin (CCT) tests had comparable sensitivities of 46% (95% CI 36, 56), 45% (95% CI 35, 55), and 47 (95% CI 37, 57), respectively, when assessed against animals positive by M. bovis culture PCR. The results suggest that test-and-slaughter control strategies using tests with low sensitivity are not expected to be effective in controlling bTB in high-prevalence herds, and highlight an urgent need to improve the sensitivity of diagnostic tests for bTB in these settings.

Objectives To describe the surgical management of ventrolateral hernias by using the vest‐over‐pants closure technique. Animals On two local breed sheep that were kept under an extensive management system. Study design Case report. Study methods Patient history and clinical findings, diagnosis, and treatment. Outcomes After frequent follow‐up and well post‐operative care, the patient were recovered. Conclusion The herniorrhaphy and closure performed in both sheep were highly successful and effective in apposing hernial ring by maintaining equal tensions with minimal wound dehiscence, unlike other closure techniques. A case report on ventrolateral herniorrhaphy in ovines.