Occult Hepatitis B virus infection among HIV negative and positive isolated anti-HBc individuals in eastern Ethiopia.

The absence of hepatitis B surface antigen (HBsAg) and the presence of antibody to hepatitis B core antigen (anti-HBc) in the blood of apparently healthy individuals may not indicate the absence of circulating hepatitis B virus (HBV) and might be infectious. Despite the risk of HBV transmission, there has been no report from Ethiopia examining this issue; therefore, this study determined occult HBV infection (OBI) among isolated anti-HBc (IAHBc) HIV negative and HIV positive individuals on ART in eastern Ethiopia. A total of 306 IAHBc individuals were included in this study. DNA was extracted, amplified, and detected from plasma using a commercially available RealTime PCR platform (Abbott m2000rt) following the manufacturer's instructions. Data were entered into EPI Data version 3.1, cleaned, and analyzed using Stata version 13. Descriptive analysis was used to calculate prevalence, summarize sociodemographic data and other factors. From the 306 IAHBc individuals (184 HIV positive and 122 HIV negative) included in the study, 183 (59.8%) were female of which 142 (77.6%) were within the reproductive age group. DNA extraction, amplified and detection was conducted in 224 individuals. The overall OBI prevalence was 5.8% (5.6% in HIV negative and 6% in HIV positive) among the IAHBc individuals. The HBV DNA concentration among the occult hepatitis B individuals was < 200 IU/mL, indicating a true occult. This study reported the burden of OBI, which pauses a significant public health problem due to the high burden of HBV infection in the country. OBI may cause substantial risk of HBV transmission from blood transfusion, organ transplantation as well as vertical transmission as screening is solely dependent on HBsAg testing.

High-throughput analysis of T cell-monocyte interaction in human tuberculosis.

The lack of efficient tools for identifying immunological correlates of tuberculosis (TB) protection or risk of disease progression impedes the development of improved control strategies. To more clearly understand the host response in TB, we recently established an imaging flow cytometer-based in-vitro assay, which assesses multiple aspects of T cell-monocyte interaction. Here, we extended our previous work and characterized communication between T cells and monocytes using clinical samples from individuals with different TB infection status and healthy controls from a TB endemic setting. To identify T cell-monocyte conjugates, peripheral blood mononuclear cells (PBMC) were stimulated with ds-Red-expressing Mycobacterium bovis bacille Calmette-Guérin or 6-kDa early secreted antigenic target (ESAT 6) peptides for 6 h, and analyzed by imaging flow cytometer (IFC). We then enumerated T cell-monocyte conjugates using polarization of T cell receptor (TCR) and F-actin as markers for synapse formation, and nuclear factor kappa B (NF-κB) nuclear translocation in the T cells. We observed a reduced frequency of T cell-monocyte conjugates in cells from patients with active pulmonary tuberculosis (pTB) compared to latent TB-infected (LTBI) and healthy controls. When we monitored NF-κB nuclear translocation in T cells interacting with monocytes, the proportion of responding cells was significantly higher in active pTB compared with LTBI and controls. Overall, these data underscore the need to consider multiple immunological parameters against TB, where IFC could be a valuable tool.

Genomic diversity and transmission dynamics of M. tuberculosis in Africa: a systematic review and meta-analysis.

BACKGROUND: Mycobacterium tuberculosis complex (MTBC) and its human host are the most competent organisms with co-evolutionary trajectory. This review determined the phylogeography, clinical phenotype-related genotype and transmission dynamics of MTBC in Africa.METHODS: Spoligotyping and mycobacterial interspersed repetitive units-variable number tandem repeats (MIRU-VNTR) based articles from Africa published in the English language were included. Articles were retrieved from PubMed and Scopus on 12 May 2018.RESULTS: In Africa, respectively 92% and 7% of tuberculosis (TB) cases were caused by M. tuberculosis and M. africanum. Among M. tuberculosis lineages (L), L4 was the predominant, at 67%, followed by L3/Central Asian (CAS; 10%). L7/ETH1 and L5/6/Maf were restricted to the Horn and Western Africa, respectively. L4.6/SIT37, H37Rv like, L4.1.2/Haarlem and H3-Ural were proportionally more frequent among tuberculous lymphadenitis (TBLN) than among pulmonary tuberculosis (PTB) cases. On 24-locus MIRU-VNTR, clustering rate was 31%; the secondary case rate from a single primary source case was 20%.CONCLUSION: Africa in general, and the east-west pole of Africa in particular, harboured a genetically diverse population of MTBC, with characteristics of geographic segregation. Both generalist and specialist genotypes are circulating in the region. L4 is dominant across the continent, while M. bovis is rarely detected as a cause for human TB. The clinical significance of genetic diversity of MTBC in the different geographic and population groups of Africa is not fully understood. Both person-to-person transmission and reactivation mode of TB is significant in Africa. Prevention and control strategies should therefore envisage these two scenarios.

Prevalence of pulmonary tuberculosis among students in three eastern Ethiopian universities.

SETTINGS: Three universities located in eastern Ethiopia: Haramaya University, Haramaya; Dire-Dawa University, Dire-Dawa; and Jigjiga University, Jigjiga. OBJECTIVE: To determine the burden of pulmonary tuberculosis (PTB) among university students and to identify risk factors for the development of TB disease. DESIGN: All full-time university students were screened for symptoms of PTB and sputum was collected for acid-fast bacilli (AFB) examination and culture for Mycobacterium tuberculosis. RESULTS: Of 35 344 students screened, we identified 153 PTB cases that occurred over the 1-year study period, or 433/100 000 students. Of these, 117 (76%) PTB cases were found through passive case finding at student health centres, while 36 (24%) previously undiagnosed patients were identified through active case finding. Sixteen cases detected using active case finding (44%) were smear-positive. Living in a dormitory with 5 students and attending university for 2 years were both significantly associated with PTB (adjusted OR 2.49 and 3.79, respectively, P < 0.001). In persons who underwent drug susceptibility testing, 11 (30.5%) had resistance to at least one first-line anti-tuberculosis drug. CONCLUSION: We found a high burden of TB among university students in eastern Ethiopia. Screening for PTB upon university admission and at regular intervals should be considered to minimise TB transmission on university campuses.

Daily adjunctive therapy with vitamin D3 and phenylbutyrate supports clinical recovery from pulmonary tuberculosis: a randomized controlled trial in Ethiopia.

OBJECTIVE: Immunotherapy using vitamin D (vitD3 ) and phenylbutyrate (PBA) may support standard drug regimens used to treat infectious diseases. We investigated if vitD3 + PBA enhanced clinical recovery from pulmonary tuberculosis (TB). METHODS: A randomized controlled trial was conducted in Addis Ababa, Ethiopia. Patients with smear-positive or smear-negative TB received daily oral supplementation with 5000 IU vitD3 and 2 × 500 mg PBA or placebo for 16 weeks, together with 6-month chemotherapy. Primary end-point: reduction of a clinical composite TB score at week 8 compared with baseline using modified intention-to-treat (mITT, n = 348) and per-protocol (n = 296) analyses. Secondary end-points: primary and modified TB scores (week 0, 4, 8, 16, 24), sputum conversion, radiological findings and plasma 25(OH)D3 concentrations. RESULTS: Most subjects had low baseline plasma 25(OH)D3 levels that increased gradually in the vitD3 + PBA group compared with placebo (P < 0.0001) from week 0 to 16 (mean 34.7 vs. 127.4 nmol L-1 ). In the adjusted mITT analysis, the primary TB score was significantly reduced in the intervention group at week 8 (-0.52, 95% CI -0.93, -0.10; P = 0.015) while the modified TB score was reduced at week 8 (-0.58, 95% CI -1.02, -0.14; P = 0.01) and 16 (-0.34, 95% CI -0.64, -0.03; P = 0.03). VitD3 + PBA had no effect on longitudinal sputum-smear conversion (P = 0.98). Clinical adverse events were more common in the placebo group (24.3%) compared with the vitD3 + PBA group (12.6%). CONCLUSION: Daily supplementation with vitD3 + PBA may ameliorate clinical TB symptoms and disease-specific complications, while the intervention had no effect on bacterial clearance in sputum.

High utility of active tuberculosis case finding in an Ethiopian prison.

SETTING: Hawassa Prison, Southern Region of Ethiopia. OBJECTIVE: To determine the burden of pulmonary tuberculosis (TB) using active case finding among prisoners. DESIGN: In this cross-sectional study, prisoners were screened for TB using a symptom screen. Those with cough of 2 weeks had spot and morning sputum samples collected for acid-fast bacilli (AFB) smear microscopy and molecular diagnostic testing (Xpert® MTB/RIF). RESULTS: Among 2068 prisoners, 372 (18%) had a positive cough screen. The median age of these 372 persons was 23 years, 97% were male and 63% were from urban areas. Among those with a positive symptom screen, 8 (2%) were AFB sputum smear-positive and 31 (8%) were Xpert-positive. The point prevalence of pulmonary TB at the prison was 1748 per 100 000 persons. In multivariate analysis, persons with cough >4 weeks were more likely to have TB (OR 3.34, 95%CI 1.54-7.23). CONCLUSION: A high prevalence of TB was detected among inmates at a large Ethiopian prison. Active case finding using a cough symptom screen in combination with Xpert had high utility, and has the potential to interrupt transmission of Mycobacterium tuberculosis in correctional facilities in low- and middle-income, high-burden countries.

Vaccination of calves with Mycobacterium bovis Bacillus Calmette-Guerin reduces the frequency and severity of lesions of bovine tuberculosis under a natural transmission setting in Ethiopia.

Bovine tuberculosis (bTB) is highly prevalent in intensive dairy farms of the urban "milk-sheds" in Ethiopia, and vaccination could be a cost-effective disease control strategy. In the present study, the efficacy of Bacillus Calmette-Guerin (BCG) to protect against bTB was assessed in Holstein-Friesian calves in a natural transmission setting. Twenty-three 2-week-old calves were subcutaneously vaccinated with BCG Danish SSI strain 1331, and matched 26 calves were injected with placebo. Six weeks later, calves were introduced into a herd of M. bovis-infected animals (reactors) and kept in contact with them for 1 year. In vitro and in vivo immunological tests were performed to assess immune responses post-vaccination and during exposure. Successful vaccine uptake was confirmed by tuberculin skin test and IFN-γ responses in vaccinated calves. The kinetics of IFN-γ responses to early secretory antigen target 6 and culture filtrate protein 10 (ESAT6 and CFP10, respectively) and tuberculin skin test responses post-exposure suggested that the animals were infected early after being placed in contact with the infected herd as immunological signs of infection were measurable between 2 and 4 months post-initial exposure. Protection was determined by comparing gross and microscopic pathology and bacteriological burden between vaccinated and control calves. BCG vaccination reduced the proportions of tissues with visible pathology in vaccinates compared to control calves by 49% (p < .001) with 56%, 43%, 72%, and 38% reductions in the proportion of lesioned tisues in head, thoracic, abdominal lymph nodes, and lungs, respectively (p-values .029-.0001). In addition, the lesions were less severe grossly and microscopically in vaccinated calves than in non-vaccinated calves (p < .05). The reduction in the overall incidence rates of bTB was 23%, 28%, and 33% on the basis of the absence of gross pathology, M. bovis culture positivity, and histopathology, respectively, in vaccinated animals. In conclusion, BCG vaccination reduced the frequency and severity of the pathology of bTB significantly, which is likely to reduce onwards transmission of the disease.

Salivary and Serum Antibody Response Against Neisseria meningitidis After Vaccination With Conjugate Polysaccharide Vaccines in Ethiopian Volunteers.

Meningococcal conjugate vaccines induce serum antibodies crucial for protection against invasive disease. Salivary antibodies are believed to be important for hindering meningococcal acquisition and/or clearance of established carriage. In this study, we measured salivary IgA and IgG antibodies induced by vaccination with a monovalent serogroup A conjugate vaccine or a tetravalent A, C, W and Y conjugate vaccine, in comparison with antibody levels in serum. Saliva and serum samples from Ethiopian volunteers (1-29 years) collected before and eight times on a weekly basis after receiving the serogroup A conjugate vaccine, the tetravalent serogroup A, C, W and Y conjugate vaccine, or no vaccine (control group), were analysed using a multiplex microsphere immunoassay for antibody detection. Serogroup-specific IgG antibody levels in saliva increased significantly after vaccination with both vaccines. The monovalent serogroup A vaccine also induced an increase in salivary IgA antibodies. A strong correlation between serogroup-specific IgG antibodies in saliva and serum, and a somewhat lower correlation for IgA, was observed for all serogroups. There was also a strong correlation between specific secretory IgA and IgA antibodies in saliva for all serogroups. Meningococcal conjugate vaccines are able to elicit salivary antibodies against serogroup A, C, W and Y correlating with antibody levels in serum. The strong correlation between saliva and serum antibody levels indicates that saliva may be used as a surrogate of systemic antibody responses.

Risk of tuberculous infection in adolescents and adults in a rural community in Ethiopia.

BACKGROUND: The incidence of tuberculosis (TB) in sub-Saharan Africa is one of the highest in the world. OBJECTIVE: To evaluate the prevalence of TB, the annual risk of tuberculous infection (ARTI) and associated risk factors in rural Ethiopia. METHODS: A tuberculin skin test was performed among 2743 individuals in a rural community of Ethiopia around Ginci town, west of Addis Ababa, to estimate the prevalence of tuberculin reactivity and to assess factors associated with tuberculous infection. RESULTS: Among 2743 volunteer participants, test results were available for 2640, 691 (26.2%) of whom had an identifiable bacille Calmette-Guérin (BCG) scar; 221 (8.3%) reported household contact with a known TB case. The overall prevalence of TST reactions of ⩾ 10 mm was 29.7%. The ARTI was estimated at 1.7%. Tuberculin reactivity varied with age, sex, income and history of household contact with a TB case. Presence of BCG scar was not related to tuberculin reactivity. CONCLUSIONS: Our findings indicate that despite an effective TB control programme, TB transmission rates are still high in rural Ethiopia. Provision of isoniazid prophylaxis in close contacts of active TB cases among the poorest population groups may reduce TB incidence.

Intensified tuberculosis case finding among HIV-infected persons using a WHO symptom screen and Xpert(®) MTB/RIF.

SETTING: Human immunodeficiency virus (HIV) clinic in Addis Ababa, Ethiopia. The World Health Organization (WHO) recommends active tuberculosis (TB) case-finding among people living with HIV (PLHIV) in high-burden settings. OBJECTIVE: To evaluate the effectiveness of combining a WHO-recommended symptom screen and the Xpert(®) MTB/RIF test to enhance TB case finding. DESIGN: In this cross-sectional study, PLHIV were screened for TB using a WHO-recommended symptom-based algorithm (cough, fever, night sweats, weight loss). Those with a positive symptom screen (⩾1 symptom) underwent diagnostic testing with smear microscopy, culture, and Xpert. RESULTS: Of 828 PLHIV (89% on antiretroviral therapy), 321 (39%) had a positive symptom screen. In multivariate analysis, an unscheduled clinic visit (aOR 3.78, 95%CI 2.69-5.32), CD4 count <100 cells/µl (aOR 2.62, 95%CI 1.23-5.59) and previous history of TB (aOR 1.62, 95%CI 1.12-2.31) were predictors of a positive symptom screen. Among those with a positive symptom screen, 6% had active pulmonary TB. Smear microscopy sensitivity for TB was poor (30%) compared to culture and Xpert. CONCLUSIONS: A positive symptom screen was common among PLHIV, creating a substantial laboratory burden. Smear microscopy had poor sensitivity for active TB disease. Given the high rate of positive symptom screen, substantial additional resources are needed to implement intensified TB case finding among PLHIV in high-burden areas.

Lipid-based nutrient supplements do not affect efavirenz but lower plasma nevirapine concentrations in Ethiopian adult HIV patients.

OBJECTIVES: Lipid-based nutrient supplements (LNSs) are increasingly used in HIV programmes in resource-limited settings. However, the possible effects of LNSs on the plasma concentrations of antiretroviral drugs have not been assessed. Here, we aimed to assess the effects of LNSs on plasma efavirenz and nevirapine trough concentrations in Ethiopian adult HIV-infected patients. METHODS: The effects of LNSs were studied in adults initiating antiretroviral therapy (ART) in a randomized trial. Patients with body mass index (BMI) > 17 kg/m(2) (n = 282) received daily supplementation of an LNS containing whey (LNS/w), an LNS containing soy (LNS/s) or no LNS. Trough plasma concentrations of efavirenz and nevirapine were measured at 1 and 2 months. Genotyping for 516 G>T and 983 T>C polymorphisms of the cytochrome P450 (CYP) 2B6 locus was performed. Multilevel linear mixed-effects models were used to assess the associations between LNS and plasma efavirenz and nevirapine concentrations. RESULTS: In patients with BMI > 17 kg/m(2), nevirapine concentrations were lower in the LNS/w and LNS/s groups by a median of -2.3 µg/mL [interquartile range (IQR) -3.9; -0.9 µg/mL; P = 0.002] and -2.1 µg/mL (IQR -3.9; -0.9 µg/mL; P = 0.01), respectively, compared with the group not receiving supplements. There were no differences between groups with respect to efavirenz plasma concentrations. The CYP2B6 516 G>T polymorphism was associated with a 5 µg/mL higher plasma efavirenz concentration compared with the wild type (P < 0.0001), while it was not associated with plasma nevirapine concentrations. CONCLUSIONS: Intake of an LNS was associated with lower plasma nevirapine trough concentrations, indicating possible drug-LNS interactions. The clinical relevance of such reductions in nevirapine exposure is not clear. Plasma efavirenz concentration was not affected by the LNS.

Effects of albendazole on the clinical outcome and immunological responses in helminth co-infected tuberculosis patients: a double blind randomised clinical trial.

Despite several review papers and experimental studies concerning the impact of chronic helminth infection on tuberculosis in recent years, there is a scarcity of data from clinical field studies in highly endemic areas for these diseases. We believe this is the first randomised clinical trial investigating the impact of albendazole treatment on the clinical and immunological outcomes of helminth co-infected tuberculosis patients. A randomised, double-blind, placebo-controlled trial of albendazole (400mg per day for 3 days) in helminth-positive tuberculosis patients was conducted in Gondar, Ethiopia. The primary outcome was clinical improvement (ΔTB score) after 2 months. Among secondary outcomes were changes in the levels of eosinophils, CD4+ T cells, regulatory T cells, IFN-γ, IL-5 and IL-10 after 3 months. A total of 140 helminth co-infected tuberculosis patients were included with an HIV co-infection rate of 22.8%. There was no significant effect on the primary outcome (ΔTB score: 5.6±2.9 for albendazole versus 5.9±2.5 for placebo, P=0.59). The albendazole-treated group showed a decline in eosinophil cells (P=0.001) and IL-10 (P=0.017) after 3 months. In an exploratory analysis after 12 weeks, the albendazole treated group showed a trend towards weight gain compared with the placebo group (11.2±8.5 kg versus 8.2±8.7 kg, P=0.08)). The reductions in eosinophil counts and IL-10 show that asymptomatic helminth infection significantly affects host immunity during tuberculosis and can be effectively reversed by albendazole treatment. The clinical effects of helminth infection on chronic infectious diseases such as tuberculosis merit further characterisation.

Avidity of IgG antibodies against meningococcal serogroup a polysaccharide and correlations with bactericidal activity in sera from meningitis patients and controls from Ethiopia.

Meningococcal meningitis is a significant global health challenge, especially for sub-Saharan area: the African meningitis belt. Neisseria meningitidis of serogroup A (MenA) is responsible for the large number of epidemics that have been recorded in these countries. To determine the level of antibodies against meningococcal A polysaccharide (APS) that correlates with protection against MenA disease in the African meningitis belt, it may be important to consider antibody avidity along with quantity. In this study, two ELISA methods using the chaotropic agent ammonium thiocyanate were compared and employed to measure avidity indexes (AI) of IgG antibodies against APS in controls and in acute and convalescent sera from Ethiopian meningococcal patients. High statistical correlations between the AIs determined by the two methods were observed. The geometric mean AI (GMAI) increased with time from acute to convalescent sera indicating affinity maturation. GMAI was significantly higher in convalescent sera from the MenA patients and in sera from the controls than in acute sera from patients with meningococcal disease. A significant correlation between serum bactericidal activity titres (SBA) and concentration of IgG antibodies against APS was observed; however, our results did not indicate that determination of antibody avidities by the thiocyanate elution method gave a better correlation with SBA than anti-APS IgG concentrations determined by the standard ELISA method.

The Ethiopian initiative to build sustainable capacity for operational research: overview and lessons learned.

SETTING: Programme-based operational research is instrumental for the enhancement of tuberculosis (TB) control. In 2012, the Ethiopian Federal Ministry of Health launched an initiative for capacity building in operational research (OR). OBJECTIVE: To develop sustainable capacity for OR in Ethiopia in a multiyear initiative. DESIGN: The initiative was developed in collaboration with regional, national and international experts. Teams representing regions in Ethiopia conducted OR addressing national and regional priorities. To make use of local expertise and increase sustainability, a domestic mentor training programme was included. Existing capacity was enhanced through a competitive grant scheme providing TB researchers with financial and technical support. The Ethiopian Tuberculosis Research Advisory Committee was also supported in its functions. Regional ethics review bodies were strengthened or established where they did not exist. RESULTS: Fifty-two people were trained and conducted 13 OR projects, of which six have been published to date. In addition, eight protocols were supported through grants. Ethics review bodies were strengthened in all regions. CONCLUSION: The initiative trained participants from all regions and succeeded in the completion of all stages of the OR process. The success of the programme can be attributed to the team approach, 'learning while doing', integrated mentorship programme and strong national ownership.

Contexte : La recherche opérationnelle programmatique joue un rôle majeur dans la lutte contre la tuberculose (TB). En 2012, le ministère éthiopien de la santé a lancé une initiative de renforcement des capacités en recherche opérationnelle (OR).Objectif : Développer des capacités pérennes d'OR en Ethiopie dans le cadre d'une initiative s'étalant sur plusieurs années.Schéma : L'initiative a été élaborée en collaboration avec des experts régionaux, nationaux et internationaux. Des équipes représentant les régions d'Ethiopie ont réalisé une OR relative aux priorités nationales et régionales. Un programme de formation de mentors domestiques a été inclus afin d'exploiter l'expertise locale et d'accroitre la pérennité. La capacité existante a été renforcée grâce à un financement compétitif offrant aux chercheurs du domaine de la TB un soutien financier et technique. Le fonctionnement du comité de concertation éthiopien sur la recherche relative à la TB a également bénéficié d'un soutien. Les comités d'éthique régionaux ont été renforcés ou créés lorsqu'ils n'existaient pas.Résultats : Cinquante-deux personnes ont été formées et ont réalisé 13 projets d'OR, dont six ont été publiés à ce jour. De plus, huit protocoles ont été soutenus par des subventions. Les comités d'éthique ont été renforcés dans toutes les régions.Conclusion: L'initiative a formé des participants de toutes les régions et ceux-ci ont terminé avec succès toutes les étapes du processus d'OR. Le succès de ce programme peut être attribué à une approche sous forme de travail d'équipe, à un apprentissage sur le tas, au programme intégré de mentors et à une forte appropriation nationale.

Marco de referencia: La práctica de investigación operativa dentro del marco programático es importante en el fortalecimiento del control de la tuberculosis (TB). En el 2012, el Ministerio Federal de Salud de Etiopía puso en marcha una iniciativa encaminada a crear capacidad de investigación operativa (OR).Objetivo: Desarrollar capacidad sostenible de OR en el país mediante una iniciativa plurianual.Método: La iniciativa se formuló en cooperación con expertos regionales, nacionales e internacionales. Varios equipos, en representación de las regiones de Etiopía, llevaron a cabo proyectos de OR que respondían a las prioridades nacionales y regionales. Con el propósito de aprovechar las competencias locales y mejorar la sostenibilidad se incorporó al proyecto un programa interno de capacitación de tutores. Se reforzó la capacidad existente mediante un plan de subvenciones otorgadas por concurso y destinado a suministrar ayuda económica y técnica a los investigadores en el campo de la TB. Asimismo, se prestó apoyo al funcionamiento del Comité Asesor de la Investigación sobre TB en Etiopía. Se reforzaron los comités de ética existentes y donde no existían se crearon nuevos comités.Resultados: Se capacitó a 52 personas y se llevaron a cabo 13 proyectos de OR, de los cuales seis han publicado sus resultados hasta la fecha. Se financiaron además ocho protocolos por conducto de las subvenciones. Se reforzaron los comités de ética en todas las regiones.Conclusión: Gracias a esta iniciativa se capacitó a los participantes provenientes de todas las regiones y se logró la compleción de todas las etapas del proceso de OR. El éxito del programa se puede atribuir a la estrategia de equipo, el aprendizaje en la acción, la integración del programa de tutoría y a una decidida apropiación nacional de la iniciativa.

Modern lineages of Mycobacterium tuberculosis in Addis Ababa, Ethiopia: implications for the tuberculosis control programe.

BACKGROUND: The genotyping of Mycobacterium tuberculosis strains is important to have unique insights into the dissemination dynamics and evolutionary genetics of this pathogen and for TB control as it allows the detection of suspected outbreaks and the tracing of transmission chains. OBJECTIVE: To characterize M. tuberculois isolates collected from newly diagnosed pulmonary TB patients in Addis Ababa METHODS: One hundred and ninety two sputum samples were cultured on Löwenstein-Jensen (LJ) slants and isolates were heat killed for molecular genotyping. The isolates were characterized using spoligotyping and were compared with the International SpoIDB4 database. RESULT: T genotype constitutes the most predominant in our study (95, 49.5%) followed by the CAS genotype (42, 21.9%). Other genotypes found were Haarlem (H) (24, 12.5%), the LAM (3, 1.5%), the Beijing genotype (1, 0.5%); four (2.1%) isolates were designated as Unknown. CONCLUSION: All the isolates belong to the modern lineage and there is high clustering in the genotype of isolates which indicated the presence of recent TB transmission. Therefore, the Tuberculosis Control Programme needs to do more in advocating and strengthening the health system for early detection and treatment of active TB cases as delay in treatment is the key factor in disease transmission.

Bovine tuberculosis in Ethiopian wildlife.

Bovine tuberculosis (BTB) is endemic in Ethiopian cattle. However, the status of the disease in wildlife populations that often share habitat with livestock is unknown. We screened for BTB in wildlife in five regions in Ethiopia. Blood and tissue samples from 133 mammals of 28 species were collected from 2006 to 2008. We used a rapid serology test (RT) based on lateral flow technology, and performed culture of lymph node specimens inoculated onto Lowenstein-Jensen and Middlebrook 7H11 media. Acid-fast colonies were further analyzed by molecular typing. Sera from 20 of 87 animals (23%) were positive for BTB by RT; acid-fast bacilli were cultured from 29 of 89 animals (32.5%). None of the positive cultures yielded mycobacteria from the Mycobacterium tuberculosis complex but many environmental mycobacteria were isolated. Among these, Mycobacterium terrae was the most common. We demonstrated a high prevalence of environmental mycobacteria in wildlife, the role of which is unknown. Flagship rare endemic species such as the mountain nyala (Tragelaphus buxtoni) and the Ethiopian wolf (Canis simensis) may be at risk for BTB. We also assessed the utility of RT for field purposes.

Repeated cross-sectional skin testing for bovine tuberculosis in cattle kept in a traditional husbandry system in Ethiopia.

Representative repeated cross-sectional skin testing for bovine tuberculosis (TB) was conducted over a period of three years in a total of 5377 cattle in three randomly selected woredas (districts) in Ethiopia (Meskan, Woldia and Bako-Gazer) that had never previously been tested for TB. Almost all (99 per cent) of the animals included local zebus kept in traditional husbandry systems. The comparative intradermal tuberculin test with two diagnostic thresholds were used to define positive test results, one according to the World Organisation for Animal Health (OIE) recommended cut-off of more than 4 mm, and the other with a cut-off of >2 mm. Data analysis was performed using a logistic regression model with a random effect at the village level. Applying the OIE definition, the overall representative apparent prevalence of bovine TB in skin test-positive local zebus was 0.9 per cent (95 per cent confidence interval [CI] 0.6 to 1.3 per cent). Using a cut-off of more than 2 mm the overall representative prevalence increased to 4 per cent (95 per cent CI 2.4 to 4.8 per cent). Due to the low apparent prevalence, the true prevalence could be calculated only in Meskan (4.5 per cent) and Bako-Gazer (2.4 per cent) for the more than 2 mm cut-off. With the exception of Meskan, prevalence by woreda did not change significantly over the years. Mycobacterium avium reactor animals were found at all study sites, but there were significant geographical variations. Overall, bulls and oxen were more at risk of being positive reactors (odds ratio [OR] 1.6, 95 per cent CI 1.1 to 2.3; OR 2, 95 per cent CI 1.4 to 2.6, respectively), as were animals in good body condition (OR 2, 95 per cent CI 1.5 to 2.9). Similar results were found at woreda level with the exception of Woldia, where none of the analysed variables was significantly associated with a positive test result.

Leishmania donovani complex (Kinetoplastida, Trypanosomatidae): comparison of deoxyribonucleic acid based techniques for typing of isolates from Ethiopia.

In Ethiopia, visceral leishmaniasis (VL) is an increasing public health concern. Recently, a new outbreak of VL claimed the lives of hundreds of Ethiopians. Mapping its distribution and the identification of the causative Leishmania species is important for proper use of resources and for control planning. The choice of appropriate typing technique is the key for determining the infecting species. Here we compared three deoxyribonucleic acid (DNA) based markers. We used, for the first time, cpbE and cpbF (cpbE/F) PCR-RFLP and demonstrated that it clearly differentiates Leishmania donovani from Leishmania infantum. The cpbE/F PCR-RFLP gave identical banding pattern for all L. donovani strains irrespective of their geographic origin. With the K26 (primers) PCR-RFLP, the L. donovani strains gave a banding pattern different from L. infantum and showed variation with geographic origin. The Ethiopian isolates typed as L. donovani by the PCR-RFLP of the cpbE/F (gene) and K26 (primers) showed two types of patterns with the T2/B4 (primers) PCR-RFLP; one group with L. infantum-like and the other L. donovani-like pattern. Phylogenetic analysis using cpbE/F sequences showed variation with geographic origin of strains and the African strains of L. donovani are more distantly related to L. infantum. Moreover, the Ethiopian isolates were seen to be closely related to the Sudanese, Kenyan and Indian strains. Thus, we recommend the use of more than one marker to study the population genetics of L. donovani complex.

Validation of bleach-treated smears for the diagnosis of pulmonary tuberculosis.

SETTING: Health centres in Awassa, southern Ethiopia. DESIGN: Consecutive patients visiting health centre laboratories for the evaluation of suspected pulmonary tuberculosis (TB) between June and September 2006 were investigated. On-the-spot, morning and second on-the-spot sputum samples were pooled for each patient. Direct smears were stained with hot Ziehl-Neelsen (ZN) technique and aliquots cultured for mycobacteria on Löwenstein-Jensen media. The remaining sputum was treated with household bleach, aliquoted and processed with short-term digestion, centrifugation and sedimentation techniques, and stained with ZN. RESULTS: Acid-fast bacilli were detected in respectively 126 (25%), 141 (28%), 169 (34%) and 198 (40%) of the 497 pooled sputum samples processed by the direct, short-term, sedimentation and centrifugation techniques (P < 0.001). The sensitivity of the direct, short-term, sedimentation and centrifugation techniques was respectively 51.1%, 53.2%, 57.6% and 63.6%. The difference between the direct smear and centrifugation (P < 0.001) or sedimentation (P < 0.005) methods was significant. The specificity of the direct, short-term digestion, sedimentation and centrifugation techniques was respectively 97%, 93%, 86.5% and 80.8%. CONCLUSIONS: Bleach treatment of sputum and centrifugation significantly improves the sensitivity of smear microscopy for the diagnosis of TB in a health centre in a high TB burden area. It is more sensitive, but possibly less specific, than other bleach methods.

Identification and Genotyping of the Etiological Agent of Tuberculous Lymphadenitis in Ethiopia

Background: In Ethiopia; little has been done to assess how Mycobacterium bovis has contributed to human tuberculosis; though the population routinely consumes unpasteurized milk and raw meat. The aim of this study was to determine the proportion of M. tuberculosis and M. bovis as etiological agents of tuberculous lymphadenitis (TBLN). Methods: Patients with lymphadenopathy (n = 171) were included in a cross-sectional study at Butajira Hospital; Southern Ethiopia. Lymph node biopsies were cultured. Patients' HIV status was identified. DNA from positive cultures was tested by PCR to identify M. bovis and M. tuberculosis. Isolates were genotyped by multiplex ligation-dependent probe amplification (MLPA) assay. Results: Among 171 patients; 156 had culture results. Of these; 107 (69) were positive for M. tuberculosis complex (MTC). Six of the 10 HIV-positive patients were culture positive. M. tuberculosis specific sequences were identified in the DNA of each of 100 samples as assessed by RD10 targeted PCR; and each of the 95 isolates exhibited the M. tuberculosis specific TbD1 deletion by MLPA analysis. No M. bovis was identified. These results indicate that all the isolates were modern M. tuberculosis strains. Furthermore; MLPA studies confirmed that 42of the isolates showed the Haarlem genotype and 12displayed sequences compatible with INH resistance. No mutations conferring resistance to ethambutol or rifampicin were detected. Conclusions: Our data showed that M. tuberculosis strains had common characteristics with strains causing pulmonary TB; which appears to be the main etiological agent of TBLN