Evaluation of the Efficacy of BCG in Protecting Against Contact Challenge With Bovine Tuberculosis in Holstein-Friesian and Zebu Crossbred Calves in Ethiopia

Bovine tuberculosis (bTB) is prevalent in intensive dairy farms in Ethiopia. Vaccination could be an alternative control approach given the socio-economic challenges of a test-and-slaughter control strategy. The efficacy of the BCG was evaluated on 40 Holstein-Friesian (HF) and zebu crossbred calves recruited from single intradermal cervical comparative tuberculin (SICCT) test negative herds and randomly allocated into two groups. Twenty-two calves were vaccinated within 2 weeks of age, and 18 were kept as a control. Six weeks post-vaccination, the two groups were exposed and kept mixed with known SICCT test positive cows for 1 year. Immune responses were monitored by interferon gamma (IFN-γ) release assay (IGRA), SICCT test, and antibody assay. Vaccinated calves developed strong responses to the SICCT test at the sixth week post-vaccination, but did not respond to ESAT-6/CFP-10 peptide antigen-based IGRA. During the exposure, IFN-γ response to the specific peptide cocktail [F(2.44, 92.67) = 26.96; p < 0.001] and skin reaction to the specific proteins cocktail [F(1.7, 64.3); p < 0.001] increased progressively in both groups while their antibody responses were low. The prevalence of bTB was 88.9% (95% CI: 65.3–98.6) and 63.6% (95% CI: 40.7–83.8) in the control and vaccinated calves, respectively, based on Mycobacterium bovis isolation, giving a direct protective efficacy estimate of 28.4% (95% CI: −2.7 to 50.1). The proportion of vaccinated calves with lesion was 7.0% (34/484) against 11.4% (45/396) in control calves, representing a 38% (95% CI: 5.8–59.4) reduction of lesion prevalence. Besides, the severity of pathology was significantly lower (Mann–Whitney U-test, p < 0.05) in vaccinated (median score = 2.0, IQR = 0–4.75) than in control (median score = 5, IQR = 3.0–6.25) calves. Moreover, survival from M. bovis infection in vaccinated calves was significantly (log-rank test: χ2 = 6.749, p < 0.01) higher than that of the control calves. In conclusion, the efficacy of BCG was low, but the reduced frequency and severity of lesion in vaccinated calves could suggest its potential role in containing onward transmission

Zoonotic tuberculosis in a high bovine tuberculosis burden area of Ethiopia

BackgroundTuberculosis (TB) is a major cause of ill health and one of the leading causes of death worldwide, caused by species of the Mycobacterium tuberculosis complex (MTBC), with Mycobacterium tuberculosis being the dominant pathogen in humans and Mycobacterium bovis in cattle. Zoonotic transmission of TB (zTB) to humans is frequent particularly where TB prevalence is high in cattle. In this study, we explored the prevalence of zTB in central Ethiopia, an area highly affected by bovine TB (bTB) in cattle.MethodA convenient sample of 385 patients with pulmonary tuberculosis (PTB, N = 287) and tuberculous lymphadenitis (TBLN, N = 98) were included in this cross-sectional study in central Ethiopia. Sputum and fine needle aspirate (FNA) samples were obtained from patients with PTB and TBLN, respectively, and cultures were performed using BACTEC™ MGIT™ 960. All culture positive samples were subjected to quantitative PCR (qPCR) assays, targeting IS1081, RD9 and RD4 genomic regions for detection of MTBC, M. tuberculosis and M. bovis, respectively.ResultsTwo hundred and fifty-five out of 385 sampled patients were culture positive and all were isolates identified as MTBC by being positive for the IS1081 assay. Among them, 249 (97.6%) samples had also a positive RD9 result (intact RD9 locus) and were consequently classified as M. tuberculosis. The remaining six (2.4%) isolates were RD4 deficient and thereby classified as M. bovis. Five out of these six M. bovis strains originated from PTB patients whereas one was isolated from a TBLN patient. Occupational risk and the widespread consumption of raw animal products were identified as potential sources of M. bovis infection in humans, and the isolation of M. bovis from PTB patients suggests the possibility of human-to-human transmission, particularly in patients with no known contact history with animals.ConclusionThe detected proportion of culture positive cases of 2.4% being M. bovis from this region was higher zTB rate than previously reported for the general population of Ethiopia. Patients with M. bovis infection are more likely to get less efficient TB treatment because M. bovis is inherently resistant to pyrazinamide. MTBC species identification should be performed where M. bovis is common in cattle, especially in patients who have a history of recurrence or treatment failure

Clinical anastomosis leakage and associated factors among patients who had intestinal anastomosis in northwest referral hospitals, Ethiopia.

BackgroundClinical anastomosis leakage leads to increased hospital costs, lengths of stay, readmissions, reoperations, and death. Therefore, this study aimed to assess clinical anastomotic leakage and associated factors among patients who had intestinal anastomosis in Northwest referral Hospitals, Ethiopia.MethodA retrospective cross-sectional study design was conducted among 411 randomly selected patients. The patient's medical records from February 2017 to February 2020 were used. The date range during which patients' medical records were extracted was from March 1 to June 2020. Patient medical record charts and data extraction sheets were used to collect the data. Data was entered into EPI-DATA version 3.1 and exported into SPSS version 25 for analysis. Binary and multiple logistic regression analysis was used to assess the association between dependent and independent variables. P-value of less than 0.05 and odds ratio with 95% CI were used to declare the presence of association.ResultsThe response rate of the study was 99.8%. Of 411 patients, 38 (9.2%) patients developed clinical anastomotic leakage. Age group 0-10 years (AOR = 6.85 95% CI: 1.742-26.97), emergency presentation (AOR = 3.196 95% CI: 1.132-9.025), and pre-operative comorbid disease (AOR = 7.62 95% CI: 2.804-20.68) were significantly associated with anastomotic leak.ConclusionsClinical anastomotic leakage is higher than the expected rate (4.9%-7.2%). Age, emergency presentation, and comorbidities were associated with clinical anastomotic leak. Hence, attention to early identification of risk factors and providing optimal pre-operative, operative, and post-operative care is necessary

Prevalence of latent tuberculosis infection and associated risk factors in prison in East Wollega Zone of western Ethiopia.

BackgroundLatent tuberculosis infection (LTBI) is the major source of active TB and is an obstacle to the strategy of World Health Organization to end TB by 2035. In Ethiopia, there are hundreds of prisons and they are conducive settings for the transmission of TB and could serve as the sources of infection to the general public. However, there is little data on the epidemiology of TB in prisons in Ethiopia. The objective of the present study was to estimate the prevalence of LTBI and evaluate associated risk factors in prisons in East Wollega Zone in western Ethiopia.MethodsA cross-sectional design and systematic sampling technique were used to select 352 prisoners from a total of 2620 prisoners during the two months (May and June, 2019). The selected inmates were consented for their willingness to participate in the study. Thereafter, they were interviewed and 2ml of blood sample was collected from each prisoner and screened for LTBI using interferon-gamma release assay (IGRA). The data were analyzed using SPSS version 25 and logistic regression was used to model the likelihood of LTBI occurrence and to identify risk factors associated with LTBI.ResultsThe prevalence of LTBI was 51.2% (95% CI: 46.45-57%) and higher prevalence was recorded in males (53%) than in females (43.5%) although the difference was not significant. Prisoners whose age ≥45 years (AOR = 2.48, 95%CI, 1.04-5.9), who chewed khat (AOR = 2.27; 95% CI, 1.27-4.19), who were prisoned over a year (AOR = 1.81, 95%CI, 1.04-3.18) and who were in overcrowded pens (AOR = 1.91, 95% CI, 1.002-3.65) were at higher risk of LTBI.ConclusionsThe prevalence of LTBI in prisoners in West Wollega Zone of western Ethiopia was high and could serve as sources of infection to the public. Hence optimum handling of prisoners, and regular follow up and treatment of TB cases in prisons were recommended to minimize the burden of TB in the Zone

Spoligotype analysis of Mycobacterium bovis isolates from cattle and assessment of zoonotic TB transmission among individuals working in bovine TB-infected dairy farms in Ethiopia.

Funder: ETHICOBOTSBovine tuberculosis (bTB) is a disease with impact on dairy productivity, as well as having the potential for zoonotic transmission. Understanding the genetic diversity of the disease agent Mycobacterium bovis is important for identifying its routes of transmission. Here we investigated the level of genetic diversity of M. bovis isolates and assessed the zoonotic potential in risk groups of people working in bTB-infected dairy farms in central Ethiopia. M. bovis was isolated and spoligotyped from tissue lesions collected from slaughtered cattle as well as from raw milk collected from bTB positive cows in dairy farms from six urban areas of central Ethiopia. From consented dairy farm workers, knowledge and practices related to zoonotic TB transmission, together with demographic and clinical information, was collected through interviews. Sputum or Fine Needle Aspirate (FNA) samples were collected from suspected TB cases. Spoligotyping of 55 M. bovis isolates that originated either from cattle tissues with tuberculous lesion or from raw milk revealed seven spoligotype patterns where SB1176 was the most prevalent type (47.3%). Most isolates (89.1%) were of the M. bovis African 2 clonal complex. All sputum and FNA samples from 41 dairy farm workers with symptoms of TB were culture negative for any mycobacteria. Among the 41 TB suspected farm workers, 61% did not know about bTB in cattle and its zoonotic potential, and over two-third of these workers practiced raw milk consumption. Our spoligotype analysis suggests a wider transmission of a single spoligotype in the study area. The results reported here may be useful in guiding future work to identify the source and direction of bTB transmission and hence design of a control strategy. Isolation of M. bovis from milk, knowledge gap on zoonotic TB and practice of consumption of raw milk in the study population showed potential risk for zoonotic transmission