Investigation of the high rates of extrapulmonary tuberculosis in Ethiopia reveals no single driving factor and minimal evidence for zoonotic transmission of Mycobacterium bovis infection

Phenotypic drug resistance and genetic mutations linked to resistance among extrapulmonary tuberculosis patients in Ethiopia: Insights from Whole Genome Sequencing

Globally, drug-resistant tuberculosis (DR-TB) is responsible for 13% of mortality attributable to antimicrobial resistance. In Ethiopia, extrapulmonary tuberculosis (EPTB) is a significant public health challenge, and drug resistance (DR) in EPTB is often overlooked. In a cross-sectional study conducted between August 2022 and October 2023, we aimed to explore the magnitude of phenotypic drug resistance and identify genetic mutations linked to resistance using 189 Mycobacterium tuberculosis (MTB) isolates cultured from extrapulmonary clinical specimens. Additionally, we assessed the agreement of the phenotypic and whole genome sequencing (WGS) based genotypic drug resistance detection. We performed phenotypic drug sensitivity testing (pDST) using liquid culture BD BACTECTM MGITTM 960 system and WGS using Illumina NextSeq500/550. The genomic data analysis pipelines MTBSeq and TBProfiler were used to predict drug resistance-conferring mutations. The agreement between the pDST and WGS was analyzed using SPSS version 29.0 software. Our result demonstrated phenotypic resistance to at least one anti-TB drug was detected in 16.9% (32/189) of the study participants. Isoniazid-resistant rifampicin-susceptible-TB (Hr-TB) and multi-drug-resistant TB (MDR-TB) phenotypes accounted for 2.6% (5/189) and 4.2% (8/189) respectively. Prevalence of MDR-TB was 2.4% (4/170) among newly diagnosed and 21.1% (4/19) among previously treated cases. WGS identified more (14/160, 8.75%) rifampicin-resistant genotypes (RR-TB) compared to pDST (8/189, 4.2%). We have identified a putative compensatory mutation for rifampicin (rpoBSer450Leu, rpoCAsp747Ala) for the first time from an EPTB clinical specimen in Ethiopia. Overall, there was a 3.75% rifampicin mono-resistant-TB(RMR-TB) genotype, which remains undetected using the conventional pDST and represented 42.9% (6/14) of the identified RR-TB genotypes. Mutations conferring rifampicin resistance-interim (rpoB.Ser450Ala) represented the majority (83.3%) of RMR-TB. Changes in ethA genes associated with ethionamide resistance were the most common resistance (n=7, 87.5%) in MDR-TB cases. There was a strong agreement between the pDST and WGS-TB Profiler pipeline to detect RR-TB (kappa=0.8) compared to the MTBSeq pipeline (k=0.58). In conclusion, MDR-TB, Hr-TB, and interim-RMR-TB are equally important public health challenges in the realm of EPTB in Ethiopia. The role of WGS is tremendous in detecting borderline/interim RMR-TB, which will help for tailored, personalized treatment strategies.

Pastoralism and Resulting Challenges for National Parks in Afar, Ethiopia

Pastoralists and national parks are key stakeholders in the management and conservation of natural and protected habitats. In Ethiopia, Afar pastoralists migrate seasonally with their livestock in search for grazing and water areas. Livestock are also a source of infectious diseases that can spread into wildlife populations when pastoralists encroach into unfenced national parks. The interactions between pastoralists and national parks, as well as the subsequent impacts, remain insufficiently understood in Afar. Two structured questionnaire surveys were conducted in 2021, including 300 pastoralist households in seven woredas of Afar, and 58 staff from three national parks (Awash, Alidegi and Yangudi Rassa). They captured pastoralist movements and livestock diseases as well as the perception of national park staff regarding challenges resulting from pastoral encroachment into parks. Among the pastoralists, 74.7% migrated with their livestock for a mean 3.5 months per year, during which time, 90% of respondents reported contact with other livestock herds, and over 80% with wildlife. A third (34.2%) reported disease outbreaks in their village prior to migration. Pastoralists traveled long distances, crossing woreda, regional or national boundaries. All 58-park respondents reported pastoralists with livestock inside their park and their close contact with wildlife. Additionally, 69% reported the presence of domestic dogs. Wildlife displacement, habitat loss and dog attacks on wildlife were perceived as the main threat caused by the presence of pastoralists, whereas diseases were only mentioned by 15.5%. Overall, park staff showed poor disease knowledge. They reported poor disease surveillance and no disease response. Within pastoral contexts, improved collaboration between wildlife and livestock authorities regarding land use, disease awareness and surveillance is needed to balance the needs of both wildlife and pastoralist's livestock development and mitigate threats to wildlife habitats.

Zoonotic tuberculosis in a high bovine tuberculosis burden area of Ethiopia

Background

Tuberculosis (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.

Method

A 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.

Results

Two 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.

Conclusion

The 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.

Comparative whole-genome sequence analysis of Mycobacterium tuberculosis isolated from pulmonary tuberculosis and tuberculous lymphadenitis patients in Northwest Ethiopia

Background

Tuberculosis (TB), caused by the Mycobacterium tuberculosis complex (MTBC), is a chronic infectious disease with both pulmonary and extrapulmonary forms. This study set out to investigate and compare the genomic diversity and transmission dynamics of Mycobacterium tuberculosis (Mtb) isolates obtained from tuberculous lymphadenitis (TBLN) and pulmonary TB (PTB) cases in Northwest Ethiopia.

Methods

A facility-based cross-sectional study was conducted using two groups of samples collected between February 2021 and June 2022 (Group 1) and between June 2020 and June 2022 (Group 2) in Northwest Ethiopia. Deoxyribonucleic acid (DNA) was extracted from 200 heat-inactivated Mtb isolates. Whole-genome sequencing (WGS) was performed from 161 isolates having ≥1 ng DNA/μl using Illumina NovaSeq 6000 technology.

Results

From the total 161 isolates sequenced, 146 Mtb isolates were successfully genotyped into three lineages (L) and 18 sub-lineages. The Euro-American (EA, L4) lineage was the prevailing (n = 100; 68.5%) followed by Central Asian (CAS, L3, n = 43; 25.3%) and then L7 (n = 3; 2.05%). The L4.2.2.ETH sub-lineage accounted for 19.9%, while Haarlem estimated at 13.7%. The phylogenetic tree revealed distinct Mtb clusters between PTB and TBLN isolates even though there was no difference at lineages and sub-lineages levels. The clustering rate (CR) and recent transmission index (RTI) for PTB were 30 and 15%, respectively. Similarly, the CR and RTI for TBLN were 31.1 and 18 %, respectively.

Conclusion and recommendations

PTB and TBLN isolates showed no Mtb lineages and sub-lineages difference. However, at the threshold of five allelic distances, Mtb isolates obtained from PTB and TBLN form distinct complexes in the phylogenetic tree, which indicates the presence of Mtb genomic variation among the two clinical forms. The high rate of clustering and RTI among TBLN implied that TBLN was likely the result of recent transmission and/or reactivation from short latency. Hence, the high incidence rate of TBLN in the Amhara region could be the result of Mtb genomic diversity and rapid clinical progression from primary infection and/or short latency. To validate this conclusion, a similar community-based study with a large sample size and better sampling technique is highly desirable. Additionally, analysis of genomic variants other than phylogenetic informative regions could give insightful information. Combined analysis of the host and the pathogen genome (GXG) together with environmental (GxGxE) factors could give comprehensive co-evolutionary information.

Burden of Mycobacterium tuberculosis and Associated Factors among Presumptive Extra pulmonary Tuberculosis Patients from Selected Health Facilities, Addis Ababa, Ethiopia

Background

Extra pulmonary tuberculosis (EPTB) accounts for a significant proportion of tuberculosis (TB), a devastating disease of public health concern. The complexity of the cases, the involvement of many organs, resource constraints, and concerns regarding drug resistance make disease diagnosis and treatment difficult. This study aimed to determine the burden of tuberculosis and associated factors among presumptive EPTB patients in selected hospitals in Addis Ababa.

Material and methods

A cross-sectional study was conducted from February to August 2022 in selected public hospitals in Addis Ababa. Those who attended the hospitals and were presumptively diagnosed as EPTB patient were included in the study. Sociodemographic and clinical data were collected using a semistructured questionnaire. The GeneXpert MTB/RIF assay, Mycobacterium Growth Indicator Tube (MGIT) culture, and solid culture using Löwenstein-Jensen (LJ) medium were used. The data were entered and analyzed using SPSS version 23, and a p-value ≤ 0.05 was considered as statistically significant.

Results

From a total of 308 participants enrolled in this study, the measured burdens of extrapulmonary tuberculosis using the Xpert MTB/RIF assay, liquid culture, and solid culture were 54 (17.5%), 45 (14.6%), and 39 (12.7%), respectively. In this study, sex, contact history with known TB cases, having a purulent type of aspirate, and being HIV positive had statistically significant associations with EPTB.

Conclusions

The burden of extrapulmonary tuberculosis among presumptive extrapulmonary tuberculosis cases was found to be significant. Sex, contact history with a known TB case, having apurulent type of aspirate, and being HIV positive were found to be associated with extrapulmonary tuberculosis infection. Strict adherence to the national tuberculosis diagnosis and treatment guidelines is important, while the true burden of the disease should be ascertained using standard diagnostic tests for better prevention and control interventions.

Comparative serum lipid and immunohematological values among adult pulmonary tuberculosis and tuberculosis lymphadenitis cases and their association with sputum bacilli load and time to culture positivity in Northwestern Ethiopia

BACKGROUND

The serum lipid and immunohematological values of tuberculosis lymphadenitis (TBLN) patients is poorly documented relative to pulmonary tuberculosis (PTB) cases. Therefore, the aim of this study was to investigate the serum lipid and immunohematological values of patients with TBLN in comparison with PTB (PTB) patients.

METHODS

An institution-based comparative cross-sectional study was conducted in Northwest Ethiopia from March to December 2021. The study participants were bacteriologically confirmed PTB (n = 82) and TBLN (n = 94) cases with no known comorbidity and whose ages was greater than 18 years and with no current pregnancy. Independent sample t-test, one-way ANOVA, box plot, and correlation matrix were used to analyze the data.

RESULTS

The body mass index (BMI), CD4 + T cell count, and high-density lipoprotein-Cholesterol (HDL-C) values were significantly higher among TBLN cases compared with PTB cases. Additionally, the total white blood cell (WBC) count, hemoglobin (Hb), total Cholesterol (CHO) and creatinine (Cr) values were relatively higher among TBLN than PTB (P > 0.05). On the reverse, the platelet count and triacylglycerol (TAG) values were relatively higher among PTB than in TBLN cases. While the mean days of culture positivity were 11.6 days for TBLN, the mean days of culture positivity were 14.0 days for PTB. Anemia and serum lipid values showed no correlation with sputum bacilli load and time to culture positivity.

CONCLUSION

Tuberculous lymphadenitis patients were well-endowed with serum lipid, immunological and nutritional status compared with PTB cases. Hence, the high incidence rate of TBLN in Ethiopia could not be explained by low peripheral immunohematological values, malnutrition, Anemia, and dyslipidemia. Further study for identifying the predictors for TBLN in Ethiopia is highly desirable.

Diagnosis and Management of Adult Tuberculosis Patients Admitted to a Rural Hospital in Ethiopia

Background  Ethiopia is one of the countries in the world with the highest rate of tuberculosis (TB). The aim of this study is to describe the characteristics of the patients with TB admitted to a rural hospital in Ethiopia in terms of both diagnosis and clinical management. Methods A retrospective descriptive observational study was conducted. Data were collected from patients older than 13 years who were admitted to the Gambo General Hospital for TB between May 2016 and September 2017. The variables studied were age, sex, symptoms, human immunodeficiency virus (HIV) serology, nutritional status, presence of anemia, chest x-ray or other complementary tests, type of diagnosis (smear microscopy, Xpert MTB-RIF (Cepheid, Sunnyvale, California, USA), or clinical diagnosis), treatment received, outcome, and days of admission. Results One hundred eighty-six patients, aged 13 years and older, were admitted to the TB unit. About 51.6% were female, and the median age was 35 years (interquartile range (IQR) 25-50). Cough was the most frequent symptom on admission (88.7%), and contact with a TB patient was only recognized by 22 patients (11.8%). HIV serology was performed in 148 patients (79.6%); seven were positive (4.7%). About 69.3% met the criteria for malnutrition (body mass index (BMI) <18.5). Most patients, 173 (93%), presented with pulmonary TB and were new cases (94.1%). Patients were diagnosed by clinical parameters in 75% of cases. Smear microscopy was performed in 148 patients, of which 46 (31.1%) were positive, and Xpert MTB-RIF results were only obtained in 16 patients, of which 6 (37.5%) were positive. Chest x-rays were performed in most patients (71%) and were suggestive of TB in 111 (84.1%). The average length of hospital stay was 32 days (confidence interval (CI) 13-50.5). Women tend to be younger than men, have more extrapulmonary TB, and were admitted longer. Nineteen patients died during admission (10.2%). Patients who die were more frequently malnourished (92.9% of those who die were malnourished compared to 67.1% of those who did not die, p = 0.036), tend to be admitted for a shorter time than the survivors and receive more concomitant antibiotic treatment. Conclusions In this rural Ethiopian setting, patients admitted to the hospital for TB are often malnourished (67.1%), the main presentation is pulmonary, mortality is one in 10 admissions and very often receive antibiotics in association with TB treatment (40%).

Bacteriologically confirmed extrapulmonary tuberculosis and the associated risk factors among extrapulmonary tuberculosis suspected patients in Ethiopia: A systematic review and meta-analysis

BACKGROUND

The actual burden of bacteriologically confirmed extrapulmonary tuberculosis (EPTB) and risk factors in Ethiopia is not well known due to the lack of a strong surveillance system in Ethiopia. Thus, this study was conducted to estimate the pooled prevalence of bacteriologically confirmed EPTB and the associated risk factors among persons suspected to have non-respiratory tuberculosis in Ethiopia.

METHODS

A systematic review and meta-analysis of published studies reporting the prevalence of EPTB from searched electronic databases; Science Direct, PubMed, and Google Scholar was estimated spread across the research periods, nationally, and in different areas, using a fixed-effects model. We used I2 to analyze heterogeneity in the reported prevalence of bacteriologically confirmed extrapulmonary tuberculosis.

RESULTS

After reviewing 938 research articles, 20 studies (19 cross-sectional and 1 retrospective) from 2003 to 2021 were included in the final analyses. The pooled prevalence of bacteriologically confirmed EPTB was 43% (95%CI; 0.34-0.52, I2 = 98.45%). The asymmetry of the funnel plot revealed the presence of publication bias. Specifically the pooled prevalence of bacteriologically confirmed EPTB based on smear microscopy, Xpert MTB/RIF assay, and culture were 22% (95%CI; 0.13-0.30, I2 = 98.56%), 39% (95%CI; 0.23-0.54, I2 = 98.73%) and 49% (95%CI; 0.41-0.57, I2 = 96.43%) respectively. In this study, a history of pulmonary tuberculosis (PTB) contact with PTB patients, contact with live animals, consumption of raw milk, HIV-positive, male, and lower monthly income, were found to be independently associated with bacteriologically confirmed EPTB.

CONCLUSION

Ethiopia has a high rate of bacteriologically confirmed EPTB. A history of previous PTB, being HIV-positive and having contact with PTB patients were the most reported risk factors for EPTB in the majority of studies. Strengthening laboratory services for EPTB diagnosis should be given priority to diagnose EPTB cases as early as possible.

Clinico-epidemiologic Considerations in the Diagnosis of Tuberculous Lymphadenitis: Evidence from a high burden country

Tuberculosis is the biggest global health issue, tuberculous lymphadenopathy (TBL) being its commonest extra-pulmonary manifestation. Clinical diagnoses of TBL often pose challenges,thus this study aimed to analyze the clinical, epidemiologic and laboratory aspects of TBL in Debre Markos Specialized Comprehensive Hospital (DMSCH), North-west Ethiopia.

METHODS

The study was conducted at DMSCH, from October 2019 to March 2021. Patients with lymphadenopathy displaying cytomorphologic features of TB were enrolled. Checklist was used to collect clinico-demographic data.

RESULTS

Among a total of 294 TBL patients, majority 237 (80.61%) were adults aged 15-45 years. A fluctuant consistency 177 (60.20%; n=294) with predominant involvement of cervical lymph nodes 229 (77.8%) was the most frequent presentation. Most patients did not have either HIV infection 235 (94.37%; n=261) or known chronic medical illnesses 250(95.8%). Constitutional symptoms 113 (41.85%; n=270) and chronic cough 56 (20.74%; n=270) were infrequent. Erythrocyte Sedimentation Rate (ESR) raised in majority 133 (80%; n=165), of whom, extreme elevation (≥ 100mm/hr) seen in 63 (38.18 %).

CONCLUSION

TBL typically present as a fluctuant neck mass, predominantly in adults. Majority patients have no constitutional symptoms or cough. HIV infection or chronic medical illnesses are uncommon. Raised ESR is a fairly consistent finding.

Knowledge of symptoms and delays in diagnosis of extrapulmonary tuberculosis patients in North Shewa zone, Ethiopia

Introduction

Delayed diagnosis contributes to the high burden and transmission of tuberculosis and extrapulmonary tuberculosis (EPTB) and continued to be a major public health problem in Ethiopia. Currently, there is insufficient knowledge on the contributing factors to diagnostic delay of EPTB patients in healthcare settings in Ethiopia, because of unique cultural and societal issues in this country. This study assessed patients’ knowledge of symptoms and contributing factors of delay in diagnosis of EPTB patients at selected public health facilities in North Shewa zone, Ethiopia.

Methods

An institutional-based study was conducted from March to April 2021. All recently registered EPTB patients were included. Logistic regression was performed to analyze the data. A significant association was declared at a p-value of < 0.05, and the results were presented with an adjusted odds ratio (AOR) and the corresponding 95% confidence interval (CI).

Results

In this study, only 15.5% of respondents knew EPTB symptoms. The median patient and healthcare system delay was 55 days. A patient delay of greater than 3 weeks and a health system delay of greater than 2 weeks were observed among 85.2% and 81% of patients, respectively. After the end of 5 weeks, 87.3% of EPTB patients had been diagnosed with the disease and the total median delay was 108.5 days. Living more than ten kilometers far from a health facility (AOR = 1.54; 95% CI = 1.11, 4.63), having never heard of EPTB disease (AOR = 5.52; 95% CI = 1.73, 17.56), and having ever taken antibiotics at the first health facility visit (AOR = 7.62; 95% CI = 2.26, 25.65) were associated with a total diagnostic delay of beyond 5 weeks.

Conclusions

The diagnostic delays of EPTB remain high. Both patient and health system delays equally contributed to the total diagnosis delay. Improving community awareness of EPTB and advancing diagnostic efficiencies of healthcare facilities could help reduce both delays.

Combination of Xpert® MTB/RIF and DetermineTM TB-LAM Ag improves the diagnosis of extrapulmonary tuberculosis at Jimma University Medical Center, Oromia, Ethiopia

BACKGROUND

Ethiopia is one of the high burden countries for extrapulmonary tuberculosis (EPTB); however, the prompt diagnosis of EPTB remains challenging. This study is aimed to evaluate the diagnostic performance of Xpert MTB/RIF and DetermineTM TB-LAM Ag (TB-LAM) for the prompt diagnosis of EPTB in Ethiopia.

METHODS

A total of 147 presumptive EPTB patients, including 23 HIV- positive participants were enrolled. Extra-pulmonary samples were collected from all presumptive EPTB cases and tested for Mycobacterium tuberculosis complex (MTBC) using fluorescent microscopy, Xpert MTB/RIF, and culture. Additionally, urine samples were also collected from 126 participants and were tested by DetermineTM TB-LAM Ag (Alere Inc, Waltham, USA). The Sensitivity and specificity of Xpert and TB- LAM tests were calculated by comparing with a composite reference standard (CRS), which comprises smear microscopy, culture and response to empirical anti-TB treatment.

RESULTS

Of 147 patients, 23 (15.6%) were confirmed EPTB cases (culture-positive), 14 (9.5%) were probable EPTB (clinically, radiologically or cytologically positive and received anti-TB treatment with good response), and 110 (74.8%) were classified as "non- TB" cases. Compared to the composite reference standard (CRS), the overall sensitivity and specificity of Xpert MTB/RIF were 43.2% and 100%, respectively with the highest sensitivity for Lymph node aspirate (85.7%) and lower sensitivity for pleural fluid (14.3%) and 100% specificity for all specimen types. The sensitivity and specificity of TB-LAM were 33.3% and 94.4% respectively with the highest sensitivity for HIV co-infected participants (83.3%). The sensitivity of the combination of Xpert MTB/RIF and TB-LAM tests regardless of HIV status was 61.1% whereas the sensitivity was improved to 83.3% for HIV-positive cases.

CONCLUSION

TB-LAM alone has low sensitivity for EPTB diagnosis; however, the combination of TB-LAM and Xpert MTB/RIF improves the diagnosis of EPTB particularly for countries with high EPTB and HIV cases.

Evaluation of Postmortem Inspection Procedures to Diagnose Bovine Tuberculosis at Debre Birhan Municipal Abattoir

Simple Summary

Tuberculosis is transmitted from animal to human by consuming raw or under cooked meat and milk from infected animals. Careful meat inspection considering all parts of the carcass is very important. However, most abattoirs in Ethiopia are performing only routine meat inspection which does not examine the organs in detail. Failure to do so might result in undetected lesions. In this study, two methods (routine and detailed meat inspections) were compared to inspect carcasses at abattoir level. Our study clearly shows that the routine meat inspection method misses about 89% of the tuberculosis lesions identified by detailed meat inspection. Based on detailed meat inspection, overall 4.7% of lesions suggestive of bovine tuberculosis (bTB) were found in the carcass of cattle slaughtered at Debre Birhan municipality abattoir during the study period. However, the routine meat inspection only detected 0.5% of the carcasses examined as having Tuberclosis (TB) lesions. Anatomically, 66% of the lesions were found in the lungs and associated lymph nodes, 21% in lymph nodes of the head, and 13% in the lymph nodes of the gastrointestinal tract. Therefore, lesion distribution routine and detailed meat inspection and their sensitivity with respect to lesion detection was identified.

Abstract

Routine meat inspection in the abattoir was used to examine carcass for subsequent approval for consumption. However, the chance of missing lesions results in approval of carcass and/or the offal with lesions of tuberculosis. A cross-sectional study was conducted at Debre Birhan Municipal abattoir from October 2016 to May 2017. Lesion prevalence estimation and two meat inspection procedures’ efficacy evaluation was attempted. The breeds of the animals inspected were zebu breeds. Routine abattoir meat inspection involves visual inspection, palpation and incision of intact organs such as the liver and kidneys, as well as inspection, palpation and incision of tracheobronchial, mediastinal and prescapular lymph nodes. The detailed meat inspection involves inspection of each of the carcass. In this case, the seven lobes of the two lungs, lymph nodes and organs were also thoroughly examined. The cut surfaces were examined under bright light sources for the presence of an abscess, cheesy mass, and tubercles in detail. The study involved and compared both routine and detailed meat inspections at the abattoir. Chi-square test of independence and odds ratio were used to see the association of lesion and different risk factors. Based on detailed meat inspection, the overall lesion prevalence of bovine tuberculosis in the carcass of cattle slaughtered at Debre Birhan municipality abattoir was found to be 4.7% but only 0.5% of the carcass examined had detectable bovine tuberculosis lesions when routine abattoir meat inspection alone was used. The majority of the lesions were distributed to the lungs and associated lymph nodes. There was a significant association (p < 0.05) in TB infection rate and body condition score. In conclusion, this study has clearly indicated the prevalence of bovine tuberculosis lesions in the abattoir that are missed by routine abattoir meat inspection. In addition, it showed low sensitivity of the routine meat inspection procedure used. Hence, our study warrants immediate attention to strengthen the current meat inspection practices at Debre Birhan public abattoir.

Diagnostic efficacy of Light-Emitting Diode (LED) Fluorescence based Microscope for the diagnosis of Tuberculous lymphadenitis

BACKGROUND

The comparatively straightforward and cheaper light-emitting diode fluorescent microscope (LEDFM) was suggested by WHO to replace conventional microscope in tuberculosis (TB) laboratories. However, the comparable efficacy of each of those techniques differs from laboratory to laboratory. We investigated the efficacy of LEDFM for the diagnosis of tuberculous lymphadenitis (TBLN) patients.

METHODS

A cross-sectional study was conducted on 211 samples from clinically suspected tuberculous lymphadenitis patients. Three smears were prepared from FNA on microscope slides for cytomorphology study, Auramine O (AO), and for Ziehl-Neelsen (ZN) staining. The left-over samples were inoculated onto Lowenstein-Jensen (LJ) media. Statistical analysis was done using STATA version 11. The sensitivity, specificity, positive and negative predictive values were calculated by considering the culture results as the gold standard using a 95% confidence interval.

RESULTS

Among 211 samples 49.7% (105) were positive by cytomorphology, 32.7% (69) by LEDFM, 23.69% (50) by LJ culture, and 13.7% (29) by ZN. Compared to the gold standard sensitivity of ZN, LEDFM, and cytomorphology were 30% [95% CI: 17.9-44.6], 66% [95% CI: 51.2-78.8] 78% [95% CI: 64-88.5], respectively. The specificity of ZN, LEDFM, and cytomorphology was 91.3% [95% CI: 85.8-95.2], 77.6% [95% CI: 70.4-83.8], 58.8% [95% CI: 50.7-66.5], respectively.

CONCLUSION

LED fluorescence microscopy gives a legitimate option in contrast to conventional ZN techniques in terms of its higher sensitivity, a bit lower specificity, time-saving, and minimal effort.

Epidemiology of Mycobacterium tuberculosis lineages and strain clustering within urban and peri-urban settings in Ethiopia

Background

Previous work has shown differential predominance of certain Mycobacterium tuberculosis (M. tb) lineages and sub-lineages among different human populations in diverse geographic regions of Ethiopia. Nevertheless, how strain diversity is evolving under the ongoing rapid socio-economic and environmental changes is poorly understood. The present study investigated factors associated with M. tb lineage predominance and rate of strain clustering within urban and peri-urban settings in Ethiopia.

Methods

Pulmonary Tuberculosis (PTB) and Cervical tuberculous lymphadenitis (TBLN) patients who visited selected health facilities were recruited in the years of 2016 and 2017. A total of 258 M. tb isolates identified from 163 sputa and 95 fine-needle aspirates (FNA) were characterized by spoligotyping and compared with international M.tb spoligotyping patterns registered at the SITVIT2 databases. The molecular data were linked with clinical and demographic data of the patients for further statistical analysis.

Results

From a total of 258 M. tb isolates, 84 distinct spoligotype patterns that included 58 known Shared International Type (SIT) patterns and 26 new or orphan patterns were identified. The majority of strains belonged to two major M. tb lineages, L3 (35.7%) and L4 (61.6%). The observed high percentage of isolates with shared patterns (n = 200/258) suggested a substantial rate of overall clustering (77.5%). After adjusting for the effect of geographical variations, clustering rate was significantly lower among individuals co-infected with HIV and other concomitant chronic disease. Compared to L4, the adjusted odds ratio and 95% confidence interval (AOR; 95% CI) indicated that infections with L3 M. tb strains were more likely to be associated with TBLN [3.47 (1.45, 8.29)] and TB-HIV co-infection [2.84 (1.61, 5.55)].

Conclusion

Despite the observed difference in strain diversity and geographical distribution of M. tb lineages, compared to earlier studies in Ethiopia, the overall rate of strain clustering suggests higher transmission and warrant more detailed investigations into the molecular epidemiology of TB and related factors.

Bovine ownership and reduced pulmonary tuberculosis risk in Nepal: A case-control study

This case-control study sought to confirm and investigate in more depth protective associations previously found of bovine (cattle and water buffalo) ownership with reduced risk of both pulmonary tuberculosis (PTB) and latent tuberculosis infection (LTBI) in humans. The study recruited male and female PTB cases from a diagnostic centre and a frequency-matched community-based control group in Kaski District, Nepal. Controls were tested for LTBI status and a separate nested case-control study was conducted based on LTBI status. Data were collected on participant household animal ownership. Using logistic regression, animal ownership was investigated for associations with both PTB and LTBI. Data were obtained from 570 PTB cases and 1,224 controls, the latter group providing 396 LTBI-positive and 692 LTBI-negative subjects. Results provided evidence of decreased odds of both PTB and LTBI positivity associated with owning bovines. The evidence was strongest for protection against infection, rather than activation of infection to PTB. Effects were strongest in women, who usually manage the animals in Nepal, and there were exposure-response relationships with numbers of bovines owned. Results suggest that exposure to bovines is protective against LTBI and PTB. A possible mechanism involves boosting the effect of BCG (Bacillus Calmette-Guerin) vaccination, particularly in protecting against tuberculous infection. Additional studies with more extensive data collection are needed to confirm the observed associations.

Phenotypic and genotypic drug sensitivity profiles of Mycobacterium tuberculosis infection and associated factors in northeastern Ethiopia

Background

Tuberculosis is a devastating and a deadly disease despite the novel advances in its diagnostic tools and drug therapy. Drug resistant Mycobacterium contributes a great share to tuberculosis mortality. Status of drug resistance and patients’ awareness toward the disease is unknown in northeastern Ethiopia. Thus, the aim of this study was to determine the phenotypic and genotypic drug sensitivity patterns and associated factors in Oromia Special Zone and Dessie Town, northeastern Ethiopia.

Methods

In a cross-sectional study, 384 smear positive tuberculosis cases were recruited and Löwenstein-Jensen culture was done. The performance of GenoTypic MTBDRplus assay using the conventional BACTEC MGIT 960 as a “gold standard” was determined. Drug resistant strains were identified using spoligotyping. Pearson Chi-square test was used to determine the association of drug sensitivity test and tuberculosis type, lineages, dominant strains and clustering of the isolates.

Results

The 384 smear positive Mycobacterium samples were cultured on LJ media of which 29.2% (112/384) as culture positive. A fair agreement was found between MTBDRplus assay and the conventional MGIT test in detecting the Mycobacterium tuberculosis with sensitivity, specificity, positive and negative predictive value of 94.2, 30.2, 68.4 and 76.5%, respectively. Among LJ culture positive samples 95 of them gave valid result for MTBDRplus assay and 16.8% (16/95) as drug resistant. Similarly, MGIT subculture was made for the 112 isolates and 69 of them gave positive result with 15.9% (11/69) as drug resistant. Cohen’s kappa value showed almost a perfect agreement between the two testing methods in detecting rifampicin (sensitivity 100% and specificity 98.3%) and multi-drug resistance (sensitivity 83.3% and specificity 100%). Spoligotyping identified 76.5% (13/17) of the drug resistant isolates as Euro-American and family 33 as the predominant family. Significant association was observed between drug resistant isolates and the dominant strains (χ2: 34.861; p = 0.040) of the Mycobacterium.

Conclusion

Higher magnitude of drug resistance was found in the study area. The GenoTypic MDRTBplus assay had an acceptable drug sensitivity testing performance.

Epidemiology and the diagnostic challenge of extra-pulmonary tuberculosis in a teaching hospital in Ethiopia

BACKGROUND

Ethiopia reported a high rate of extra-pulmonary tuberculosis (EPTB) and the cases are increasing since the last three decades. However, diagnostic evidence to initiate TB treatment among EPTB cases is not well known. Therefore, we described the epidemiology and assessed how EPTB is diagnosed in a teaching hospital in Ethiopia.

METHODS

We conducted a retrospective review among all adult EPTB cases diagnosed in Yekatit 12 Hospital Medical College from 2015 to 2019. Using a standardized data abstraction sheet, we collected data from patients' medical records on sociodemographic, sites, and laboratory diagnosis of EPTB cases.

RESULTS

Of the 965 total TB cases, 49.8%(481) had a recorded diagnosis of EPTB during the study period. The mean age of EPTB patients was 32.9 years (SD±13.9) and 50.7% were males. Tubercular lymphadenitis (40.3%), abdominal (23.4%), and pleural TB(13.5%) were the most common sites of EPTB involvement, followed in descending order by the genitourinary, skeletal, central nervous system, abscess, breast, and laryngeal TB. We found a histopathology finding consistent with EPTB in 59.1% of cases, Acid-fast bacilli positive in 1.5%, and the rest diagnosed on radiological grounds. In the majority of cases, more than one diagnostic method was used to diagnose EPTB cases.

CONCLUSIONS

Nearly half of TB patients had a recorded diagnosis of EPTB that comprise heterogeneous anatomical sites. All EPTB patients were started anti-TB therapy without definitive microbiology results. This indicates the diagnostic challenge of EPTB faced in our setting and proves to be significant for TB control in Ethiopia.

Genetic diversity of the Mycobacterium tuberculosis complex strains from newly diagnosed tuberculosis patients in Northwest Ethiopia reveals a predominance of East-African-Indian and Euro-American lineages

OBJECTIVES

This study described the population structure of M. tuberculosis complex (MTBc) strains among patients with pulmonary or lymph node tuberculosis (TB) in Northwest Ethiopia and tested the performance of culture isolation and MPT64-based speciation for Lineage 7 (L7).

METHODS

Patients were recruited between April 2017 and June 2019 in North Gondar, Ethiopia. The MPT64 assay was used to confirm MTBc, and spoligotyping was used to characterize mycobacterial lineages. Line probe assay (LPA) was used to detect resistance to rifampicin and isoniazid.

RESULTS

Among 274 MTBc genotyped isolates, there were five MTBc lineages: L1-L4 and L7 were identified, with predominant East-African-Indian (L3) (53.6%) and Euro-American (L4) (40.1%) strains, and low prevalence (2.6%) of Ethiopia L7. The genotypes were similarly distributed between pulmonary and lymph node TB, and all lineages were equally isolated by culture and recognized as MTBc by the MPT64 assay. Additionally, LPA showed that 259 (94.5%) MTBc were susceptible to both rifampicin and isoniazid, and one (0.4%) was multi-drug resistant (resistant to both rifampicin and isoniazid).

CONCLUSION

These findings show that TB in North Gondar, Ethiopia, is mainly caused by L3 and L4 strains, with low rates of L7, confirmed as MTBc by MPT64 assay and with limited resistance to rifampicin and isoniazid.

Cancer obscures extrapulmonary tuberculosis (EPTB) at a tertiary hospital in Northern Malawi

Data on the prevalence of extrapulmonary tuberculosis (EPTB) patients are limited in many African countries including Malawi. We conducted a retrospective review of all histology reports for cancer suspected patients at Mzuzu Central Hospital (MZCH) between 2013 and 2018 to determine the proportion of EPTB cases among cancer suspected patients and characterised them epidemiologically. All reports with inconclusive findings were excluded. In total, 2214 reports were included in the review, 47 of which reported EPTB, representing 2.1% (95% CI 1.6-2.8). The incidence of EPTB was significantly associated with sex, age and HIV status. Men were more than twice (OR 2.1; 95% CI 1.2-3.9) as likely to have EPTB as women while those with HIV were more than six times (OR 6.4; 95% CI 1.7-24.8) as likely to have EPTB compared to those who were HIV-negative. EPTB demonstrated an inverse relationship with age. The highest proportion of EPTB was found from neck lymph nodes (10.3% (5.4-17.2)). A reasonable number of EPTB cases are diagnosed late or missed in Malawi's hospitals. There is a need for concerted efforts to increase EPTB awareness and likely come up with a policy to consider EPTB as a differential diagnosis in cancer suspected patients.

Molecular epidemiology of clinical Mycobacterium tuberculosis complex isolates in South Omo, Southern Ethiopia

BACKGROUND

Tuberculosis (TB) is caused by Mycobacterium tuberculosis complex (MTBC). Mapping the genetic diversity of MTBC in high TB burden country like Ethiopia is important to understand principles of the disease transmission and to strengthen the regional TB control program. The aim of this study was to investigate the genetic diversity of Mycobacterium tuberculosis complex (MTBC) isolates circulating in the South Omo, southern Ethiopia.

METHODS

MTBC isolates (N = 156) were genetically analyzed using spacer oligotyping (spoligotyping) and mycobacterial interspersed repetitive unit-variable number of tandem repeat (MIRU-VNTR) typing. Major lineages and lineages were identified using MTBC databases. Logistic regression was used to correlate patient characteristics with strain clustering.

RESULTS

The study identified Euro-American (EA), East-African-Indian (EAI), Indo-Oceanic (IO), Lineage_7/Aethiops vertus, Mycobacterium bovis and Mycobacterium africanum major lineages in proportions of 67.3% (105/156), 22.4% (35/156), 6.4% (10/156), 1.9% (3/156), 1.3% (2/156) and 0.6% (1/156), respectively. Lineages identified were Delhi/CAS 23.9% (37/155), Ethiopia_2 20.6% (32/155), Haarlem 14.2% (22/155), URAL 14.2%(22/155), Ethiopia_3 8.4% (13/155), TUR 6.5% (10/155), Lineage_7/Aethiops vertus 1.9% (3/155), Bovis 1.3% (2/155), LAM 1.3% (2/155), EAI 0.6% (1/155), X 0.6% (1/155) and Ethiopia H₃₇Rv-like strain 0.6% (1/155). Of the genotyped isolates 5.8% (9/155) remained unassigned. The recent transmission index (RTI) was 3.9%. Orphan strains compared to shared types (AOR: 0.09, 95% CI: 0.04-0.25) were associated with reduced odds of clustering. The dominant TB lineage in pastoral areas was EAI and in non-pastoral areas was EA.

CONCLUSION

The epidemiological data, highly diverse MTBC strains and a low RTI in South Omo, provide information contributing to the TB Control Program of the country.

Prevalence of bovine tuberculosis in slaughtered cattle and factors associated with risk of disease transmission among cattle handlers at Oko-Oba Abattoir, Lagos, Nigeria

Background and Aim:

Bovine tuberculosis (bTB) is a zoonotic disease of major public health importance, especially in many developing countries, including Nigeria, where control measures are largely not applied, and the risks of human infection are high. This study was aimed at determining the current prevalence of bTB in slaughtered cattle and identifying factors associated with the risk of disease transmission among cattle handlers toward making informed control measures to limit human-animal interface disease transmission.

Materials and Methods:

Serum samples at slaughter and lesions suggestive of bTB collected during postmortem examination of 187 slaughtered cattle at the Oko–Oba Abattoir, Agege, Lagos State, Nigeria, were subjected to lateral flow and Ziehl–Neelsen (ZN) techniques, respectively. Furthermore, a structured questionnaire was interviewer-administered to 156 cattle handlers to investigate associated exposure factors to bTB infection. Data were analyzed using bivariate and multivariate logistic regression.

Results:

The prevalence of bTB in cattle was 25.7% and 7.0% by lateral flow technique and ZN, respectively. The seropositivity was highest in cattle with poor body condition (50.0%), then with good (36.4%) and fair (25.0%) body conditions. The questionnaire survey revealed that being in livestock handling business for >6 years (p=0.001), not knowing the mode of transmission (p=0.02) and ignoring TB lesions at slaughter (p=0.02) were exposure factors associated with increased risk of bTB infection among the cattle handlers. Further, multivariate analysis showed that those who spent more than 6 years in livestock handling were about 4 times (Adjusted odds ratio [AOR]=3.5; 95% confidence interval [CI]=1.1-7.6, p=0.01) more likely to be exposed to bTB infection than those with lesser years. Again, respondents who called the attention of meat inspectors on seeing lesions in animals were about 4 times less likely to be exposed to bTB infection than those who ignored it (AOR=0.3; CI=0.1-0.8, p=0.01).

Conclusion:

This study has reiterated the endemicity of bTB in cattle population in Nigeria, with the prevalence of 25.7% and 7.0% of bTB by lateral flow and ZN techniques, respectively. This portends potential risk for disease transmission at the human-animal interface, particularly at the abattoir setting. The study also identified important knowledge and practice gaps which would enable informed, all-inclusive, and well-directed programs for effective control of the disease in both human and cattle populations.

Incidence, risk factors and clinical characteristics of extra-pulmonary tuberculosis patients: a ten-year study in the North of Iran

OBJECTIVE

To determine the incidence of extra-pulmonary tuberculosis (EPTB) and examine the risk factors and the clinical features of the disease over a ten-year period.

METHODS

Retrospective study of records of patients who were followed and registered in the TB registry programme in the health district of Gorgan, Iran from January 1, 2008, through December 31, 2017.

RESULTS

Among 2280 TB records, 609 (26.71%) were EPTB. They were mostly female patients (53.7%) and residents in rural areas (56.5%) with a mean age of 40.55 years [±16]. The average age of female patients (37.55 years [±16.99]) was lower than of male patients (44.07 years [±20.59]). The median of the incidence rate was 7.5 per 100 000 inhabitants for EPTB; biopsy and pathology were the best methods for the detection of EPTB. The most frequent forms of EPTB were lymphatic TB (193/609 = 31.7%) and pleural TB (158/609 = 25.9%). In most cases (245/609 = 40.2%), one to three months elapsed between occurrence of symptoms and final confirmation of EPTB. The outcome of EPTB was weaker than of pulmonary TB (PTB).

CONCLUSION

Our most important finding was the increasing incidence of EPTB, which shows the importance of attention to this disease. Lymph node and pleural tissue were the most commonly infected tissues. Skeletal TB presents a challenge in the diagnosis and treatment of EPTB.

High helminthic co-infection in tuberculosis patients with undernutritional status in northeastern Ethiopia

BACKGROUND

Tuberculosis and parasitosis are the widely distributed diseases in Ethiopia with the leading cause of mortality and morbidity, respectively. There has been no information on the status of co-infections of tuberculosis and parasitosis in Oromia Zone of Amhara Region and South Wollo, Ethiopia. Hence, this study primarily focuses on determining the status of tuberculosis and parasitosis co-infections and associated factors.

METHODS

The study was conducted in Oromia Special Zone of the Amhara Regional State and South Wollo Zone, northeastern Ethiopia from April 2015 to January 2017. Tuberculosis cases confirmed by health personnel at the health institutions were the source of the study sample. In a cross-sectional study 384 smear positive pulmonary and extra-pulmonary tuberculosis cases were recruited. Faecal specimens provided by the study participants were examined for parasitic co-infections using direct saline microscopic test, Kato-Katz and concentration techniques. Nutritional status was determined using body mass index and mid-upper arm circumferences. Data were analyzed using descriptive statistical methods and Pearson chi-square.

RESULTS

Tuberculosis and parasitosis co-infection prevalence was 10.8%, and the proportion of intestinal helminths accounted for 9.7% while intestinal protozoa accounted for 1.9%. Cases with single parasitic infection was 89.3% among co-infected individuals. Co-infection of both disease was not significantly associated with gender and age (P > 0.05). The prevalence of undernutrition was 58.6% as determined using body mass index and 73.0% as determined using mid-upper arm circumference with no significant association with gender. Among all forms of tuberculosis cases (384) screened for the study, the bacterial positivity was relatively more common in males (55.5%) than females (44.5%). Tuberculosis lymphadenitis was found to be the most prevalent (85.9%) form of extra-pulmonary tuberculosis with cervical adenopathy (75.3%) being the commonly existing disease.

CONCLUSIONS

The rate of helminthic co-infection is predominantly high than that of intestinal protozoa. Single parasitic co-infection was more common than double or multiple co-infections. Both body mass index and mid-upper arm circumference anthropometric parameters revealed greater risk of undernutrition in tuberculosis patients. Thus, screening and prompt treatment of parasites in tuberculosis patients and a support of nutritional supplementation for malnourished tuberculosis patients should be further studied which might enhance the disease treatment and minimize the risk of its complexity.

Evaluation of the immunogenicity and efficacy of BCG and MTBVAC vaccines using a natural transmission model of tuberculosis

Effective vaccines against tuberculosis (TB) are needed in order to prevent TB transmission in human and animal populations. Evaluation of TB vaccines may be facilitated by using reliable animal models that mimic host pathophysiology and natural transmission of the disease as closely as possible. In this study, we evaluated the immunogenicity and efficacy of two attenuated vaccines, BCG and MTBVAC, after each was given to 17 goats (2 months old) and then exposed for 9 months to goats infected with M. caprae. In general, MTBVAC-vaccinated goats showed higher interferon-gamma release than BCG vaccinated goats in response to bovine protein purified derivative and ESAT-6/CFP-10 antigens and the response was significantly higher than that observed in the control group until challenge. All animals showed lesions consistent with TB at the end of the study. Goats that received either vaccine showed significantly lower scores for pulmonary lymph nodes and total lesions than unvaccinated controls. Both MTBVAC and BCG vaccines proved to be immunogenic and effective in reducing severity of TB pathology caused by M. caprae. Our model system of natural TB transmission may be useful for evaluating and optimizing vaccines.

Retrospective Analysis of Archived Pyrazinamide Resistant Mycobacterium tuberculosis Complex Isolates from Uganda-Evidence of Interspecies Transmission

The contribution of Mycobacterium bovis to the proportion of tuberculosis cases in humans is unknown. A retrospective study was undertaken on archived Mycobacterium tuberculosis complex (MTBC) isolates from a reference laboratory in Uganda to identify the prevalence of human M. bovis infection. A total of 5676 isolates maintained in this repository were queried and 136 isolates were identified as pyrazinamide resistant, a hallmark phenotype of M. bovis. Of these, 1.5% (n = 2) isolates were confirmed as M. bovis by using regions of difference PCR analysis. The overall size of whole genome sequences (WGSs) of these two M. bovis isolates were ~4.272 Mb (M. bovis Bz_31150 isolated from a captive chimpanzee) and 4.17 Mb (M. bovis B2_7505 from a human patient), respectively. Alignment of these genomes against 15 MTBC genome sequences revealed 7248 single nucleotide polumorphisms (SNPs). Theses SNPs were used for phylogenetic analysis that indicated a strong relationship between M. bovis and the chimpanzee isolate (Bz_31150) while the other M. bovis genome from the human patient (B2_7505) analyzed did not cluster with any M. bovis or M. tuberculosis strains. WGS analysis also revealed multidrug resistance genotypes; these genomes revealed pncA mutations at positions H57D in Bz_31150 and B2_7505. Phenotypically, B2_7505 was an extensively drug-resistant strain and this was confirmed by the presence of mutations in the major resistance-associated proteins for all anti-tuberculosis (TB) drugs, including isoniazid (KatG (S315T) and InhA (S94A)), fluoroquinolones (S95T), streptomycin (rrs (R309C)), and rifampin (D435Y, a rare but disputed mutation in rpoB). The presence of these mutations exclusively in the human M. bovis isolate suggested that these occurred after transmission from cattle. Genome analysis in this study identified M. bovis in humans and great apes, suggesting possible transmission from domesticated ruminants in the area due to a dynamic and changing interface, which has created opportunity for exposure and transmission.

Epidemiology of tuberculous lymphadenitis in Africa: A systematic review and meta-analysis

INTRODUCTION

Tuberculous lymphadenitis is the most frequent form of extra-pulmonary TB (EPTB) and accounts for a considerable proportion of all EPTB cases. We conducted a systematic review of articles that described the epidemiological features of TBLN in Africa.

METHODS

Any article that characterized TBLN cases with respect to demographic, exposure and clinical features were included. Article search was restricted to African countries and those published in English language irrespective of publication year. The articles were retrieved from the electronic database of PubMed, Scopus, Cochrane library and Lens.org. Random effect pooled prevalence with 95% CI was computed based on Dersimonian and Laird method. To stabilize the variance, Freeman-Tukey double arcsine root transformation was done. The data were analyzed using Stata 14.

RESULTS

Of the total 833 articles retrieved, twenty-eight articles from 12 African countries fulfilled the eligibility criteria. A total of 6746 TBLN cases were identified. The majority of the cases, 4762 (70.6%) were from Ethiopia. Over 77% and 88% of identified TBLN were cervical in type and naïve to TB drugs. Among the total number of TBLN cases, 53% were female, 68% were in the age range of 15-44 years, 52% had a history of livestock exposure, 46% had a history of consuming raw milk/meat and 24% had history of BCG vaccination. The proportion of TBLN/HIV co-infection was much lower in Ethiopia (21%) than in other African countries (73%) and the overall African estimate (52%). Fever was recorded in 45%, night sweating in 55%, weight loss in 62% and cough for longer than two weeks in 32% of the TBLN cases.

CONCLUSIONS

TBLN was more common in females than in males. The high prevalence of TBLN in Ethiopia did not show directional correlation with HIV. Population based prospective studies are warranted to better define the risk factors of TBLN in Africa.

Polymorphisms in CARD8 and NLRP3 are associated with extrapulmonary TB and poor clinical outcome in active TB in Ethiopia

Innate immunity is a first line defense against Mycobacterium tuberculosis infection where inflammasome activation and secretion of the pro-inflammatory cytokine IL-1beta, plays a major role. Thus, genetic polymorphisms in innate immunity-related genes such as CARD8 and NLRP3 may contribute to the understanding of why most exposed individuals do not develop infection. Our aim was to investigate the association between polymorphisms in CARD8 and NLRP3 and active tuberculosis (TB) as well as their relationship to treatment outcome in a high-endemic setting for TB. Polymorphisms in CARD8 (C10X) and NLRP3 (Q705K) were analysed in 1190 TB patients and 1990 healthy donors (HD). There was a significant association between homozygotes in the CARD8 polymorphism and extrapulmonary TB (EPTB), which was not the case for pulmonary TB or HDs. Among TB-patients, there was an association between poor treatment outcome and the NLRP3 (Q705K) polymorphism. Our study shows that inflammasome polymorphisms are associated with EPTB and poor clinical outcome in active TB in Ethiopia. The practical implications and determining causal relationships on a mechanistic level needs further study.

Risk factors assessment of bovine tuberculosis among abattoir personnel in Gombe State, Northeastern Nigeria: A One-Health approach

Aim: Bovine tuberculosis (bTB) is an important milk-borne zoonosis that affects cattle production and poses serious threat to public health. This study aimed at assessing the risk factors as well as the level of awareness, attitude, and practices of abattoir personnel toward bTB in Gombe Township Abattoir, Gombe State. Materials and Methods: A prospective survey was conducted between October 2015 and December 2015. During the survey, a total of 112 close-ended structured questionnaires were administered to the abattoir personnel to assess their level of awareness of bTB. Results: Of these respondents, the majority were males (79%), butchers (49%) and about 40% were under the productive age brackets of 26-35 years. Majority of the respondents (85.7%) were aware of the zoonotic nature of the disease. However, only a few of the respondents (44.6%) wear personal protective equipments (PPEs) clothes while handling or in contact with carcasses during the slaughtering process. Only a few among the respondents (24.1% and 31.2%) consumed unpasteurized milk and unaware of eating of improperly cooked meat as a risk factor of bTB, respectively. About 75.7% of the respondents believed that the habit of eating and drinking inside the abattoir and during slaughtering operations has no any significant effects on their health. The results obtained show a statistically significant association between respondents' awareness of bTB and their occupational status, duration of exposure to cattle carcasses, and knowledge about the disease (p<0.05); and the odds of being aware of bTB was 10.0, 5.07, and 4.2, respectively. Conclusion: This study demonstrates the need for public health authorities to intervene in bTB prevention and control through the creation of avenues for enlightenment on the zoonotic risk associated with bTB. The risk factors associated with bTB transmission as indicated by the personnel's practice and awareness levels in Gombe township abattoir are preventable through the use of PPEs clothing.

Epidemiology of Mycobacterium bovis and Mycobacterium tuberculosis in animals: Transmission dynamics and control challenges of zoonotic TB in Ethiopia

Mycobacterium tuberculosis complex is the cause of tuberculosis (TB) in humans and other animals. Specifically, Mycobacterium bovis (M. bovis) and Mycobacterium tuberculosis (M. tuberculosis) are highly pathogenic mycobacteria that may infect different animal species and are the sources of TB in humans. The objective of this paper was to review the epidemiology of M. bovis and M. tuberculosis in animals. The review also highlighted the transmission dynamics of M. bovis and M. tuberculosis in humans and animals and control challenges of zoonotic TB in Ethiopia. The literature review focused on scientific peer-reviewed articles from studies exclusively conducted in Ethiopia that were published from 1998 to 2017. Husbandry system, breed and herd size have significant role in the epidemiology of bovine tuberculosis (BTB) in Ethiopia. The information presented reveals that different strains of M. bovis are widely distributed in domestic animals predominantly in the Ethiopian cattle and the main strain was found to be SB1176. In addition, the isolation of M. tuberculosis from domestic animals in different settings signifies the circulation of the agent between humans and animals in Ethiopia. The life styles of the Ethiopian communities, close contact with domestic animals and/or the habit of consuming raw animal products, are suggested as the main factors for transmission of M. bovis and M. tuberculosis between human and animal which may have impact on the TB control program in human. In Ethiopia, a human TB control program has been widely implemented, however, the role of animal in the transmission of the causative agent has been neglected which could be one of the challenges for an effective control program. This warrants the need for incorporating animal TB control programs using "One Health" approach for effective TB control for both human and animal.

Treatment outcomes of tuberculosis patients under directly observed treatment short-course at Debre Tabor General Hospital, northwest Ethiopia: nine-years retrospective study

BACKGROUND

Data regarding tuberculosis (TB) treatment outcomes, proportion of TB/HIV co-infection and associated factors have been released at different TB treatment facilities in Ethiopia and elsewhere in the world as part of the auditing and surveillance service. However, these data are missing for the TB clinic offering directly observed treatment short-course (DOTs) at Debre Tabor General Hospital (DTGH).

METHODS

The authors analysed the records of 985 TB patients registered at the DTGH from September 2008 to December 2016. Data on patients' sex, age, type of TB, and treatment outcomes were extracted from the TB treatment registration logbook. The treatment outcome of patients was categorized according to the National TB and Leprosy Control Program guidelines: cured, treatment completed, treatment failed, died, and not evaluated (transferred out and unknown cases).

RESULTS

Around half of the registered patients were males (516, 52.4%). In terms of TB types, 381 (38.7%), 241 (24.5%), and 363 (36.9%) patients had smear-negative pulmonary TB, smear-positive pulmonary TB, and extra pulmonary TB, respectively. Six hundred and seventy-two patients (90.1%) had successful treatment outcomes (cured and treatment completed), while 74 patients (9.9%) had unsuccessful treatment outcomes (death and treatment failure).TB treatment outcome was not associated with age, sex, type and history of TB, or co-infection with HIV (P > 0.05). The proportion of TB/HIV co-infection was at 24.2%, and these were found to be significantly associated with the age groups of 25-34, 35-44 and ≥65 years:(aOR: 0.44; 95% CI: 0.25-0.8), (aOR: 0.39; 95% CI: 0.20-0.70), (aOR: 4.2; 95% CI: 1.30-12.9), respectively.

CONCLUSIONS

The proportion of patients with successful treatment outcomes was above the World Health Organization target set for Millennium Development Goal of 85% and in line with that of the global milestone target set at > 90% for 2025. Relatively higher proportions of transfer-out cases were recorded in the present study. Similarly, the proportion of TB/HIV co-infection cases was much higher than the national average of 8%.Thus, the health facility under study should develop strategies to record the final treatment outcome of transfer-out cases. In addition, strategies to reduce the burden of TB/HIV co-infection should be strengthened.

The predominance of Ethiopian specific Mycobacterium tuberculosis families and minimal contribution of Mycobacterium bovis in tuberculous lymphadenitis patients in Southwest Ethiopia

BACKGROUND

Ethiopia has an extremely high rate of extrapulmonary tuberculosis, dominated by tuberculous lymphadenitis (TBLN). However, little is known about Mycobacterium tuberculosis complex (MTBc) lineages responsible for TBLN in Southwest Ethiopia.

METHODS

A total of 304 MTBc isolates from TBLN patients in Southwest Ethiopia were genotyped primarily by spoligotyping. Isolates of selected spoligotypes were further analyzed by 15-loci mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) (n=167) and qPCR-based single nucleotide polymorphism (n=38). Isolates were classified into main phylogenetic lineages and families by using the reference strain collections and identification tools available at MIRU-VNTRplus data base. Resistance to rifampicin was determined by Xpert MTB/RIF.

RESULTS

The majority of isolates (248; 81.6%) belonged to the Euro-American lineage (Lineage 4), with the ill-defined T and Haarlem as largest families comprising 116 (38.2%) and 43 (14.1%) isolates respectively. Of the T family, 108 isolates were classified as being part of the newly described Ethiopian families, namely Ethiopia_2 (n=44), Ethiopia_3 (n=34) and Ethiopia_H₃₇Rv-like (n=30). Other sub-lineages included URAL (n=18), S (n=17), Uganda I (n=16), LAM (n=13), X (n=5), TUR (n=5), Uganda II (n=4) and unknown (n=19). Lineage 3 (Delhi/CAS) was the second most common lineage comprising 44 (14.5%) isolates. Interestingly, six isolates (2%) were belonged to Lineage 7, unique to Ethiopia. Lineage 1 (East-African Indian) and Lineage 2 (Beijing) were represented by 3 and 1 isolates respectively. M. bovis was identified in only two (0.7%) TBLN cases. The cluster rate was highest for Ethiopia_3 isolates showing clonal similarity with isolates from North Ethiopia. Lineage 3 was significantly associated with rifampicin resistance.

CONCLUSIONS

In TBLN in Southwest Ethiopia, the recently described Ethiopia specific Lineage 4 families were predominant, followed by Lineage 3 and Lineage 4-Haarlem. The contribution of M. bovis in TBLN infection is minimal.

Breaking Transmission with Vaccines: The Case of Tuberculosis

Members of the Mycobacterium tuberculosis complex (MTBC) have evolved causing tuberculosis (TB) in different mammalian hosts. MTBC ecotypes have adapted to diverse animal species, with M. bovis being the most common cause of TB in livestock. Cattle-to-human transmission of M. bovis through ingestion of raw milk was common before introduction of the pasteurization process. TB in humans is mainly caused by M. tuberculosis. This bacterium is considered a genetically clonal pathogen that has coevolved with humans due to its ability to manipulate and subvert the immune response. TB is a major public health problem due to airborne person-to-person transmission of M. tuberculosis. The essential yet unanswered question on the natural history of TB is when M. tuberculosis decides to establish latent infection in the host (resambling the lysogenic cycle of lambda phage) or to cause pulmonary disease (comparable to the lytic cycle of lambda phage). In this latter case, M. tuberculosis kills the host with the aim of achieving transmission to new hosts. Combating the TB epidemic requires stopping transmission. M. bovis BCG, the present vaccine against TB, is derived from M. bovis and only protects against disseminated forms of TB. Thus, a priority in TB research is development of new effective vaccines to prevent pulmonary disease. Attenuated vaccines based on M. tuberculosis as MTBVAC are potential candidates that could contribute to break the TB transmission cycle.

Profile and treatment outcomes of patients with tuberculosis in Northeastern Ethiopia: a cross sectional study

BACKGROUND

Data on the epidemiology of tuberculosis and its treatment outcomes were incomplete in the study area and this study was done to fill this gap.

METHODS

Institution based cross sectional study was conducted from January 2011 to December 2014. A total of 949 TB patients who were on treatment in North Eastern Ethiopia, Eastern Amhara region were included. Data was analyzed using SPSS version 20. Frequency, percentages and means were used to present data. To assess the associations of treatment outcomes with sex, age, type of TB and human immunodeficiency virus (HIV), logistic regression was used.

RESULTS

The proportion of smear positive and negative pulmonary TB, and extra pulmonary TB were 187/949 (19.7%), 322/949 (33.9%) and 440/949 (46.4%), respectively. Treatment success rate was 853/949 (89.9%). Smear positive pulmonary TB and TB/HIV co-infections were significantly associated with unsuccessful treatment outcome, P≤ 0.002.

CONCLUSION

Extra pulmonary TB was the most prevalent types of TB followed by smear negative pulmonary TB. Treatment success rate was above the WHO target of 85%. The causes for the high proportion of smear negative PTB and EPTB should be further investigated. Special emphasis should be put on smear positive PTB patients and TB/HIV co-infected patients to decrease unsuccessful treatment outcome and TB transmissions.

Molecular epidemiology of Mycobacterium africanum in Ghana

Background

Mycobacterium africanum comprises two phylogenetic lineages within the M. tuberculosis complex (MTBC) and is an important cause of human tuberculosis (TB) in West Africa. The reasons for this geographic restriction of M. africanum remain unclear. Here, we performed a prospective study to explore associations between the characteristics of TB patients and the MTBC lineages circulating in Ghana.

Method

We genotyped 1,211 MTBC isolates recovered from pulmonary TB patients recruited between 2012 and 2014 using single nucleotide polymorphism typing and spoligotyping. Associations between patient and pathogen variables were assessed using univariate and multivariate logistic regression.

Results

Of the 1,211 MTBC isolates analysed, 71.9 % (871) belonged to Lineage 4; 12.6 % (152) to Lineage 5 (also known as M. africanum West-Africa 1), 9.2 % (112) to Lineage 6 (also known as M. africanum West-Africa 2) and 0.6 % (7) to Mycobacterium bovis. Univariate analysis revealed that Lineage 6 strains were less likely to be isoniazid resistant compared to other strains (odds ratio = 0.25, 95 % confidence interval (CI): 0.05–0.77, P < 0.01). Multivariate analysis showed that Lineage 5 was significantly more common in patients from the Ewe ethnic group (adjusted odds ratio (adjOR): 2.79; 95 % CI: 1.47–5.29, P < 0.001) and Lineage 6 more likely to be found among HIV-co-infected TB patients (adjOR = 2.2; 95 % confidence interval (CI: 1.32–3.7, P < 0.001).

Conclusion

Our findings confirm the importance of M. africanum in Ghana and highlight the need to differentiate between Lineage 5 and Lineage 6, as these lineages differ in associated patient variables.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-1725-6) contains supplementary material, which is available to authorized users.

Tuberculosis among transhumant pastoralist and settled communities of south-eastern Mauritania

Background

Transhumant pastoralists of Mauritania were assumed to have a high prevalence of tuberculosis (TB) because of reduced access to diagnostic testing. No population-based survey on TB has been published for Mauritania.

Objective

The goal of this study was to estimate the prevalence of presumptive TB cases among mobile pastoralists and villagers in a remote zone of Mauritania.

Design

In the south-eastern province of Hodh Ech Chargui, 250 adult pastoralists and 250 villagers were randomly enrolled using multistage cluster sampling in February 2012. A TB centre nurse examined participants using a standard clinical protocol, and a participant questionnaire was completed. Focus group discussions and interviews were conducted with community members and health personnel, respectively.

Results

Fourteen new presumptive TB cases were identified, leading to an overall prevalence of 2.8%, (95% confidence interval (CI) 1.5–4.7%). The prevalence was non-significantly higher among villagers than pastoralists (3.6% vs. 2.0%). Assuming illness duration was 3 years and all presumptive cases started treatment, an overall crude incidence of 933 cases/100,000 was derived. Five of six presumptive cases in Djiguenni were confirmed by sputum smear microscopy, but none out of eight presumptive cases were confirmed in Néma, although the same nurse performed all clinical examinations in both departments. This result was attributed to the use of expired reagents in Néma. Communities mentioned distance rather than lack of information as the main constraint to seeking diagnosis, but poor diagnostic centre performance also delayed decision-making.

Conclusions

TB prevalences were high among both pastoralists and villagers. None of the 14 presumptive cases sought prior diagnostic testing. TB diagnostic centres in the remote rural study zone were poorly equipped. These centres must remain in operation to reduce TB incidence in vulnerable communities in insecure remote rural zones and to reach national health goals.

Abattoir-based estimates of mycobacterial infections in Cameroon

Mycobacteria cause major diseases including human tuberculosis, bovine tuberculosis and Johne’s disease. In livestock, the dominant species is M. bovis causing bovine tuberculosis (bTB), a disease of global zoonotic importance. In this study, we estimated the prevalence of Mycobacteria in slaughter cattle in Cameroon. A total of 2,346 cattle were examined in a cross-sectional study at four abattoirs in Cameroon. Up to three lesions per animal were collected for further study and a retropharyngeal lymph node was collected from a random sample of non-lesioned animals. Samples were cultured on Lowenstein Jensen media and the BACTEC MGIT 960 system, and identified using the Hain^® Genotype kits. A total of 207/2,346 cattle were identified with bTB-like lesions, representing 4.0% (45/1,129), 11.3% (106/935), 23.8% (38/160) and 14.8% (18/122) of the cattle in the Bamenda, Ngaoundere, Garoua and Maroua abattoirs respectively. The minimum estimated prevalence of M. bovis was 2.8% (1.9–3.9), 7.7% (6.1–9.6), 21.3% (15.2–28.4) and 13.1% (7.7–20.4) in the four abattoirs respectively. One M. tuberculosis and three M. bovis strains were recovered from non-lesioned animals. The high prevalence of M. bovis is of public health concern and limits the potential control options in this setting without a viable vaccine as an alternative.

Mycobacterium tuberculosis Complex and HIV Co-Infection among Extrapulmonary Tuberculosis Suspected Cases at the University of Gondar Hospital, Northwestern Ethiopia

Background

Extrapulmonary Tuberculosis (EPTB) and Human Immunodeficiency Virus (HIV) infection are interrelated as a result of immune depression. The aim of this study was to determine the prevalence of Mycobacterium tuberculosis complex isolates and the burden of HIV co-infection among EPTB suspected patients.

Method

An institution based cross-sectional study was conducted among EPTB suspected patients at the University of Gondar Hospital. Socio-demographic characteristics and other clinical data were collected using a pretested questionnaire. GeneXpert MTB/RIF assay was performed to diagnosis Mycobacterium tuberculosis complex and Rifampicin resistance. All samples were also investigated by cytology and culture. The HIV statuses of all patients were screened initially by KHB, and all positive cases were further re-tested by STAT-pack. Data was analyzed using SPSS version 20 computer software and a P-value of < 0.05 was taken as statistically significant.

Results

A total of 141 extrapulmonary suspected patients were enrolled in this study. The overall prevalence of culture confirmed extrapulmonary tuberculosis infection was 29.8%, but the GeneXpert result showed a 26.2% prevalence of Mycobacterium tuberculosis complex infection. The 78.4% prevalence of extrapulmonary tuberculosis infection was found to be higher among the adult population. The prevalence of HIV infection among EPTB suspected patients was 14.1%, while it was 32.4% among GeneXpert-confirmed extrapulmonary TB cases (12/37). Tuberculosis lymphadenitis was the predominant (78.4%) type of EPTB infection followed by tuberculosis cold abscess (10.7%). Adult hood, previous history of contact with known pulmonary tuberculosis patients, and HIV co-infection showed a statistically significant association with extrapulmonary tuberculosis infection (P<0.013).

Conclusion

The prevalence of culture confirmed-EPTB infection was high, and a higher EPTB-HIV co-infection was also observed.

TB/HIV co-infections and associated factors among patients on directly observed treatment short course in Northeastern Ethiopia: a 4 years retrospective study

Background

Human immunodeficiency virus (HIV) and tuberculosis (TB) are the leading independent global causes of death among patients with infectious diseases. Additionally, due to the shared immune defense mechanisms, they are the leading cause of co-morbidities globally. However, little information was found regarding the proportion of TB/HIV co-infection in the study area. Thus, this study determined the proportion and associated factors of TB/HIV co-infection.

Methods

All TB patients treated from January/2011 to December/2014 were included in this study. Data were collected from three health centers namely; Kobo, Robit and Gobiye. Data were entered, cleared, and analyzed using SPSS version 20. Frequency, percentage, median and range were used to present the data. To assess the associated factors, logistic regression was employed.

Results

Of the total 990 TB patients enrolled in the study, 98.2 % were screened for HIV; of these, 24.3 % were co-infected with TB and HIV. The odds of having TB/HIV co-infection were 3.4 times higher among in the age group of 25–45 years compared to older (≥45 years) age TB patients (OR = 3.4; 95 % CI 2–5). Moreover, the odds of having TB/HIV co-infection were 2.8 and 1.7 times higher among smear positive and smear negative patients with pulmonary TB respectively than patients with extra pulmonary TB. Of 236 co-infected patients, 71.2 % took co-trimoxazole preventive therapy and 76.3 % took antiretroviral treatment.

Conclusion

TB/HIV co-infection is one of the serious public health problems in the study area. Thus, Collaborative TB/HIV activities that reduce the co-morbidities and mortalities should be addressed.