Cytomorphological patterns and clinical features of presumptive tubercular lymphadenitis patients and their comparison with bacteriological detection methods: a cross-sectional study.

INTRODUCTION: Tuberculous lymphadenitis (TBLN) is an infection of the lymph node caused by Mycobacterium tuberculosis. Histological diagnoses of presumptive patients are often accompanied by cytomorphological features. However, the sensitivities of these features are often precluded by the variable degrees of narrative similarities compared to other diagnostic modalities. OBJECTIVE: The aim of this study was to investigate and compare the cytomorphological and clinical features of presumptive TBLN patients with bacteriological detection methods. METHODS: A similar cohort of TBLN patients from our previous study who were enrolled prospectively from the ALERT Specialized Hospital, Addis Ababa, Ethiopia, was considered for this analysis. SPSS version 26 was used for data analysis. Descriptive analysis was conducted to characterize the study population using the independent variable and presented with frequency tables. The chi-square test was used to measure the association. A P-value of < 0.05 was considered statistically significant. RESULTS: Using FNAC, 60/126 (47.6%) of the participants were reported to have features consistent with TB. Of the total FNAC-positive cases, many (30/60 and 27/60) showed pattern B (caseous necrosis only) and pattern C (epithelioid granuloma with caseous necrosis), respectively. Strong concordance was observed in Pattern A (abundant caseous necrosis with few epithelioid macrophages) followed by patterns B and C with GeneXpert and MGIT culture (P value < 0.001). Night sweats and alcohol intake were shown to correlate with positive cases as reported by FNAC (P value = 0.008 respectively), GeneXpert (P value = 0.02 & 0.001), and culture methods (P-value = < 0.001 & 0.002). CONCLUSION: Cytomorphological features, particularly patterns A, B, and C, could be considered in the diagnosis of TBLN given their comparable outcomes with bacteriological detection methods. On another note, we recommend that due care and attention be given when treating TBLN patients based solely on clinical presentation, as these diagnostics may be prone to false results, leading to inappropriate administration of anti-TB drugs and other consequences.

Mycobacterium tuberculosis antigen-specific T-cell responses in smear-negative pulmonary tuberculosis patients.

Despite recent improvements in microbial detection, smear-negative TB remains a diagnostic challenge. In this study, we investigated the potential discriminatory role of polychromatic flow cytometry of M. tuberculosis antigen-specific T cells to discriminate smear-negative TB from health controls with or without latent TB infection, and non-TB respiratory illnesses in an endemic setting. A cross-sectional study was conducted on HIV negative, newly diagnosed smear-positive PTB (n = 34), smear-negative/GeneXpert negative PTB (n = 29) patients, non-TB patients with respiratory illness (n = 33) and apparently healthy latent TB infected (n = 30) or non-infected (n = 23) individuals. The expression of activation (HLA-DR, CD-38), proliferation (Ki-67), and functional (IFN-γ, TNF-α) T-cell markers using polychromatic flow cytometry was defined after stimulation with PPD antigens. Sputum samples were collected and processed from all patients for Mtb detection using a concentrated microscopy, LJ/MGIT culture, and RD9 typing by PCR. Our study showed CD4 T cells specific for PPD co-expressed activation/proliferation markers together with induced cytokines IFN-γ or TNF-α were present at substantially higher levels among patients with smear-positive and smear-negative pulmonary TB than among healthy controls and to a lesser extent among patients with non-TB illness. Our study conclude that smear-negative TB can be distinguished from non-TB respiratory illness and healthy controls with a flow cytometric assay for PPD-specific T cells co-expressing activation/proliferation markers and cytokines.

High seroprevalence of anti-SARS-CoV-2 antibodies among Ethiopian healthcare workers.

BACKGROUND: COVID-19 pandemic has a devastating impact on the economies and health care system of sub-Saharan Africa. Healthcare workers (HWs), the main actors of the health system, are at higher risk because of their occupation. Serology-based estimates of SARS-CoV-2 infection among HWs represent a measure of HWs' exposure to the virus and could be used as a guide to the prevalence of SARS-CoV-2 in the community and valuable in combating COVID-19. This information is currently lacking in Ethiopia and other African countries. This study aimed to develop an in-house antibody testing assay, assess the prevalence of SARS-CoV-2 antibodies among Ethiopian high-risk frontline HWs. METHODS: We developed and validated an in-house Enzyme-Linked Immunosorbent Assay (ELISA) for specific detection of anti-SARS-CoV-2 receptor binding domain immunoglobin G (IgG) antibodies. We then used this assay to assess the seroprevalence among HWs in five public hospitals located in different geographic regions of Ethiopia. From consenting HWs, blood samples were collected between December 2020 and February 2021, the period between the two peaks of COVID-19 in Ethiopia. Socio-demographic and clinical data were collected using questionnaire-based interviews. Descriptive statistics and bivariate and multivariate logistic regression were used to determine the overall and post-stratified seroprevalence and the association between seropositivity and potential risk factors. RESULTS: Our successfully developed in-house assay sensitivity was 100% in serum samples collected 2- weeks after the first onset of symptoms whereas its specificity in pre-COVID-19 pandemic sera was 97.7%. Using this assay, we analyzed a total of 1997 sera collected from HWs. Of 1997 HWs who provided a blood sample, and demographic and clinical data, 51.7% were females, 74.0% had no symptoms compatible with COVID-19, and 29.0% had a history of contact with suspected or confirmed patients with SARS-CoV-2 infection. The overall seroprevalence was 39.6%. The lowest (24.5%) and the highest (48.0%) seroprevalence rates were found in Hiwot Fana Specialized Hospital in Harar and ALERT Hospital in Addis Ababa, respectively. Of the 821 seropositive HWs, 224(27.3%) of them had a history of symptoms consistent with COVID-19 while 436 (> 53%) of them had no contact with COVID-19 cases as well as no history of COVID-19 like symptoms. A history of close contact with suspected/confirmed COVID-19 cases is associated with seropositivity (Adjusted Odds Ratio (AOR) = 1.4, 95% CI 1.1-1.8; p = 0.015). CONCLUSION: High SARS-CoV-2 seroprevalence levels were observed in the five Ethiopian hospitals. These findings highlight the significant burden of asymptomatic infection in Ethiopia and may reflect the scale of transmission in the general population.

Ex vivo mRNA expression of toll-like receptors during latent tuberculosis infection.

BACKGROUND: Understanding immune mechanisms, particularly the role of innate immune markers during latent TB infection remains elusive. The main objective of this study was to evaluate mRNA gene expression patterns of toll-like receptors (TLRs) as correlates of immunity during latent TB infection and further infer their roles as potential diagnostic biomarkers. METHODS: Messenger RNA (mRNA) levels were analysed in a total of 64 samples collected from apparently healthy children and adolescents latently infected with tuberculosis (n = 32) or non-infected (n = 32). Relative expression in peripheral blood of selected genes encoding TLRs (TLR-1, TLR-2, TLR-4, TLR-6 and TLR-9) was determined with a quantitative real-time polymerase chain reaction (qRT-PCR) using specific primers and florescent labelled probes and a comparative threshold cycle method to define fold change. Data were analysed using Graph-Pad Prism 7.01 for Windows and a p-value less than 0.05 was considered statistically significant. RESULTS: An increased mean fold change in the relative expression of TLR-2 and TLR-6 mRNA was observed in LTBI groups relative to non-LTBI groups (p < 0.05), whereas a slight fold decrease was observed for TLR-1 gene. CONCLUSIONS: An increased mRNA expression of TLR-2 and TLR-6 was observed in latently infected individuals relative to those non-infected, possibly indicating the roles these biomarkers play in sustenance of the steady state interaction between the dormant TB bacilli and host immunity.

Phenotypic and functional heterogeneity of peripheral γδ T cells in pulmonary TB and HIV patients in Addis Ababa, Ethiopia.

BACKGROUND: Previous studies reported HIV infection alters the distribution and function of γδ T cells and their subsets. γδ T phenotypes in healthy and diseased individuals has received little attention in Ethiopia. We conducted this study to analyze the distribution of γδ T cells, the subsets and levels of expression of activation (CD38), exhaustion or anergy (CD95, PD1), adhesion (N-CAM/CD56 and CD103), among HIV and TB infected patients. METHOD: The distributions of total γδ T cells, Vδ1 and Vδ2 T cells subsets were analyzed in clinical samples collected from asymptomatic HIV, pulmonary TB patients and apparently healthy controls. Multicolor flow cytometry and IFN-γ ELISA were used to assess surface markers and functional responses of Vδ2 T cells to isopentenyl pyrophosphate stimulation, respectively. RESULT: A total of 52 study participants were enrolled in this study, 22 HIV + TB-, 10 HIV-TB+ and 20 healthy controls. No significant differences were observed in the distribution of total γδ T cells and in the proportion of Vδ1 subsets in all study groups, though slightly higher proportions were observed in HIV + TB- patients for the latter, of borderline statistical significance (p = 0.07). However, the proportion of Vδ2 T cells, as well as the IFN-γ response to IPP stimulation, was significantly reduced in HIV + TB- patients compared to healthy controls (p < 0.002). Expression of the activation marker CD38 (p < 0.001) and adhesion marker CD103 (αEß7) were significantly higher in the Vδ1 T cell subset among both HIV + TB- (p = 0.013) and HIV-TB+ (p = 0.006) patients compared to healthy controls. Similarly, exhaustion markers, CD95 and PD1, were significantly higher in these two T cell subsets among both HIV + TB- and HIV-TB+ patients (p < 0.01). Interestingly, we also observed an increased proportion of effector memory (CD45RA-CD27-) and effector cytotoxic (CD45RA + CD27-) Vδ2 T cell subsets in HIV negative pulmonary TB patients. CONCLUSION: In sum, HIV infection was associated with an increase in Vδ1 and a decrease in the function and frequencies of Vδ2 T cells. Moreover, increased effector Vδ2 T cells were observed among HIV negative pulmonary TB patients suggesting a potential role of these T cells in the host response to TB.

Research ethics review practices: experiences of the Armauer Hansen Research Institute/All Africa Leprosy and Tuberculosis Rehabilitation and Training Center Ethics Review Committee, Ethiopia.

The need for ethics review committees (ERCs) is imperative in the conduct of research to ensure the protection of the rights, safety and well-being of research participants. However, the capacities of most ERCs in Africa are limited in terms of trained experts, competence, resources as well as standard operating procedures. The aim of this report is to share experiences of one of the local institutional ERCs, the Armauer Hansen Research Institute (AHRI)/All Africa Leprosy and Tuberculosis Rehabilitation and Training Center (ALERT) Ethics Review Committee (AAERC), to other ERCs found in academic and research institutions in the Country. In this report, we used an empirical approach to review archived documents of the AAERC Secretariat to assess the Committee's strengths and weaknesses. The experiences of the AAERC in terms of its composition, routine work activities, learning practices and pitfalls that require general attention are summarized. In spite of this summary, the Committee strongly acknowledges the functions and roles of other ERCs in the Country. In addition, an independent assessment of the Committee's activity in general is warranted to evaluate its performance and further assess the level of awareness or oversights among researchers about the roles of ERCs.

Assessment of cost of tuberculosis to patients and their families: a cross-sectional study at Addet Health Center, Yilmana Densa District, Amhara National Regional State.

INTRODUCTION: The rising number of tuberculosis cases is putting a considerable strain on health budgets, and threatens to drain resources essential to health and welfare services. OBJECTIVES: The objective of this study was to estimate the cost of tuberculosis to outpatients and their families in a rural district health center, Addet Health Center, Yilmana Densa District, Amhara National Regional State in Ethiopia. METHODS: Cross-sectional study was conducted to estimate the cost of tuberculosis to outpatients and their families. Data were collected on diagnosis, treatment, transportation, food and other expenses, and also income losses due to tuberculosis before and after the diagnosis of tuberculosis. Data were entered to Epi-Info and transferred to SPSS 13 for analysis. Mean, median, range and standard deviation were used to describe the data. RESULT: The mean direct cost and indirect cost of tuberculosis to outpatients and their families were 1078.00 Birr and 2080.43 Birr, respectively, at the time of study. The mean total cost of tuberculosis to outpatients and their families was 3159.23 Birr. CONCLUSION: Cost of tuberculosis to patients and their families, especially before the identification of the disease was found to be very high. Therefore, consequences of tuberculosis to patients and their families are particularly serious and potentially devastating.

Tuberculosis among Addis Ababa city bus drivers and cash collectors.

BACKGROUND: The risk of transmission of tuberculosis is high in crowded conditions. Addis Ababa has a relatively high burden of tuberculosis and its city buses are often filled with commuters. Tuberculosis is a potential occupational hazard for city bus drivers and cash collectors. OBJECTIVES: The objective of this study was to estimate the proportion of tuberculosis among city bus drivers and cash collectors. METHODS: We estimated the proportion of tuberculosis of all forms among city bus drivers and cash collectors of the Addis Ababa City Bus Organization, from January 2003 to December 2004. Study participants were screened with clinical, bacteriological and chest X-ray examination from January 2003 to December 2004. RESULTS: Sixteen cases of tuberculosis were identified among 903 study participants (466 city bus drivers and 437 cash collectors) examined, of whom 12 were already on anti-TB treatment and 4 were diagnosed during the study. The proportion of all forms of tuberculosis, smear-positive pulmonary tuberculosis and extra-pulmonary tuberculosis was 16/903 (1772/100,000), 4/903 (443/100,000) and 3/903(332/100,000), respectively. CONCLUSION AND RECOMMENDATIONS: The proportion of all forms of tuberculosis among the study population was higher than the notification case rates for Addis Ababa reported in 2003, which indicates the need for a routine screening of city bus drivers and cash collectors. Measures such as opening windows and reducing crowding in buses are recommended as a means of reducing the risk of exposure to bus drivers and cash collectors.

Human immunodeficiency virus infection among new smear positive pulmonary tuberculosis patients in Addis Ababa, Ethiopia.

BACKGROUND: It has been few years since the launching of provider-initiated HIV counselling and testing (PICT) for all tuberculosis (TB) suspected patients and patients presenting with signs and symptoms of TB. However, little is known about the prevalence of HIV in new smear positive confirmed TB cases in Addis Ababa. OBJECTIVE: To determine the proportion of HIV among newly diagnosed smear positive TB cases, who were screened between February 2007 and July 2010 in Addis Ababa. METHODS: A total of 418 pulmonary TB patients and 188 HIV positive non-TB cases were recruited from different health centres in Addis Ababa. All TB patients were tested for HIV. RESULTS: Of the total 418 new smear positive TB patients tested for HIV, 97 (23.2%) were HIV positive. The occurrence of HIV among TB patients was significantly higher in females, 50/182 (27.7%) compared to males, 47/236 (19.7%) (P < 0.05). The mean CD4 lymphocyte count among HIV positive active TB cases was significantly lower (P < 0.05) (210 +/- 23.9 cells/microL) compared to the counts among non-TB HIV positive cases (407.01 +/- 31.3 cells/microL). The proportion of HIV was significantly higher in the age group 31-40 (46.3%) and > 41 (42.2%) year (p < 0.001) compared to younger, 18-20 (3.75%) and 21-30 (17.8%) years of age groups. CONCLUSION: The occurrence of HIV in smear positive TB cases is high, with a higher proportion seen among females compared to males.

Characterization of the etiological agents of tuberculous lymphadenitis in Dera Woreda, North Showa, Ethiopia.

BACKGROUND: Tuberculous lymphadenitis (TBLN) is a common form of extra pulmonary tuberculosis where lymph nodes particularly from cervical, axillary and inguinal sites are mostly involved, however, its diagnosis poses a major challenge in resource limited settings. OBJECTIVE: To identify the etiological species of Mycobacteria responsible for TBLN in Derra area, a rural district in Ethiopia, where the status of TBLN is unknown. MATERIALS AND METHODS: A total of 153 patients who were clinically suspected for TBLN, between the periods of August 2004 and February 2005 were included in the study. Fine needle aspirates (FNA) were collected and processed from 145 participants and further analyzed using Ziehl Neelsen staining, culture, cytology and polymerase chain reaction (PCR) using sets of primers, targeting the IS6110 insertion sequence and the pncA gene allelic variation at position 169. RESULTS: Out of the 145 FNA samples, 66 (45.5%) demonstrated growth on Lowenstein-Jensen (LJ) medium and 115 (79.3%) cases were confirmed as TBLN by a combination of results from acid fast bacilli (AFB) smear examination, culture, cytology and PCR. From the 145 clinically suspected TBLN cases, 108 (75%) were identified by PCR at complex level of which 107/108 (99.1%) were positive for M. tuberculosis and 1/108 (0.9%) was positive for M. bovis using pncA primers. CONCLUSION: The study indicates that M. tuberculosis is the major cause of tuberculous lymphadenitis in Dera area.

T cell response to alpha crystallin and Mycobacterium tuberculosis specific antigens using ex-vivo elispot assay for detecting latent tuberculosis infection in Addis Ababa, Ethiopia.

BACKGROUND: Mycobacterium tuberculosis (Mtb) persists in a state of non-replication or stationary phase, but resulting in active tuberculosis (TB) when the immune system is suppressed. Alpha-crystallin (ACR) is one of the bacterial antigens characterized known to be related to shifting of the bacilli from growth to a non-replicating persistent state. OBJECTIVE: To compare the ex-vivo responsiveness of active TB patients, close household contacts and healthy controls to specific Mtb antigens. METHODOLOGY: Antigen-specific interferon-gamma (IFN-g) responses were measured to a 16kDa-alpha crystallin (ACR) antigen along with its peptides and other Mtb antigens (ESAT-6, CFP-10, PPD, TB10.3 and Ag85A) in 39 active TB patients, 23 close household contacts and 25 community controls, using ex-vivo ELISPOT RESULT: The proportion of responders to ACR was 36% in active TB patients (76 +/- 14 spot forming cells), 48% in close household contacts (123 +/- 31 spot forming cells) and 76% in community controls (165 +/- 29 spot forming cells) indicating the presence of latency more in the community controls compared to the other groups. Sixty percent of community controls (131 +/- 27 spot forming cells), 61% of healthy household contacts (138 +/- 3 spot forming cells) and 54% of TB patients (198 +/- 37 spot forming cells) showed ESAT-6-specific T cell responses. CONCLUSION: Antigen specific T cell response based on ex-vivo ELISPOT assay using combined ACR and ESAT-6/ CFP-10 antigens can be used as indicator of underlying latent TB infection in tropical setting where tuberculosis is endemic.

Chronic meningitis in immunocompromised adult Ethiopians visiting Tikur Anbessa Teaching Hospital and Ye'huleshet Clinic from 2003-2004.

BACKGROUND: Chronic meningitis is inflammation of the meninges where signs and symptoms develop and last for at least four weeks without alleviation. Little is known about the current etiology and incidence of the disease in adults living in developing countries. OBJECTIVE: The objective of this study was to elucidate the most common etiologies of chronic meningitis in adult Ethiopian patients and give an aid in the empiric therapy. METHODOLOGY: A total of 53 adult patients (median age 32 years) having chronic meningitis and who were admitted at Tikur Anbessa Teaching Hospital and Ye'huleshet Clinic, Addis Ababa, Ethiopia were recruited between 2003 and 2004. Of the 53 patients, bacteriological, molecular and immunological investigations were done for 52 of the study participants to detect Cryptococcus neoformans, Mycobacterium tuberculosis, Toxoplasma gondii, Brucella and Neisseria meningitides infections. RESULTS: Forty eight of the participants were HIV positive and 15% (8/52) of the CSF were positive with Cryptococcal latex antigen detection test; in addition, M. tuberculosis DNA was detected using PCR from CSF ofpatients infew of the patients. Multiple infections were observed in studyparticipants with < 0.1 to 1 CD4 to CD8 ratio. CONCLUSION: Chronic meningitis mostly occurred in HIV infected patients, where most of the infections were attributed to Cryptococcus neoformans whereas M. tuberculosis appeared secondary.

A pilot study on detection and genotyping of humanpapilloma virus isolated from clinically diagnosed Ethiopian women having cervical intraepithelial neoplasia.

BACKGROUND: Human Papilloma virus associated cervical cancers are more prevalent in developing countries compared to developed countries. Cervical cancer is reported as the most frequent malignancy among women visiting hospitals in Ethiopia. This study is a pilot study designed to examine the prevalence and genotypes of HPV in twenty Ethiopian women, clinically diagnosed to have cervical neoplasia, while visiting gynecology unit of a tertiary level referral hospital in Addis Ababa. The objective of this study was to detect the presence of HPV L1 gene and respective genotypes among women clinically diagnosed with different grades of cervical neoplasia. METHODOLOGY: A total of 20 fresh biopsy samples were collected from clinically diagnosed cases, DNA extracted and further amplified using PCR for HPV L1 and beta globin genes. The PCR amplicons were denatured and allowed for hybridization onto a nitrocellulose strip containing the type-specific probes for 27 HPV genotypes representing both high and low risk groups as well as beta globin genes. Socio-demographic characteristics and clinical findings of the participants were recorded on structured questionnaires. RESULTS: Amplification of HPV L1 gene by PCR detected 17 cases out of 20. Based on reverse line blot hybridization assay, the most frequent genotype identified was HPV16 (13/20). Mixed infection of HPV 16 with HPV 33, HPV 35, HPV 45 and HPV 58 was detected from other four study participants. CONCLUSION: Human papilloma virus type 16 was the most prevalent genotype identified from the subjects screened. Further investigation with statistically sound sample size would help to clearly visualize the existing trend in Ethiopia regarding factors for high risk HPV positivity and multiple gravidity, young age at first coitus and cervical neoplasia.

Recent trends of cutaneous leishmaniasis in Alert Hospital, Addis Ababa.

BACKGROUND: Cutaneous leishmaniasis is endemic to many parts of the world and has re-emerged in a number of endemic countries in recent years. Environmental changes, immune status of the host and treatment failure are the three most important risk factors associated with the re-emerging and spread of Leishmaniasis. Cutaneous leishmaniasis (CL) ranges from localized, self-healing type to the disfiguring mucocutaneous and diffuse cutaneous type. OBJECTIVE: To access the trend of CL patient flow in ALERT Hospital, Addis Ababa, Ethiopia. METHODS: Patients' clinical and laboratory records were collected retrospectively for 1651 leishmaniasis suspected individuals from ALERT Hospital, from January 1, 2007 to December 30, 2010. RESULTS: From the suspected individuals, 234 cases were positive for Leishmania species with Giemsa stain and/or histopathology and confirmed for CL, of whom 30 (12.8%) were diagnosed in 2007, 29 (12.4%) in 2008, 75 (32.1%) in 2009, and 100 (42.7%) were in 2010. CONCLUSIONS AND RECOMMENDATIONS: The overall proportion of cases with leishmaniasis among the suspected cases was 234/1651 (14.2%). The distribution of CL reports was higher for patients coming from Addis Ababa surrounding areas and Oromia region, 96/234 (41.03%) and 71/234 (30.34%), respectively. In general, the trend of leishmaniasis in and around Addis Ababa seems to be increasing, which calls for further detailed epidemiological studies, including vector and reservoir host studies, to help in the prevention and control of the disease.

Protein Expression of TLR2, TLR4, and TLR9 on Monocytes in TB, HIV, and TB/HIV.

Toll-like receptors (TLRs) have a critical role in recognizing pathogenic patterns and initiating immune responses against TB and HIV. Previously, studies described the gene expression of TLRs in patients with TB and HIV. Here, we demonstrated TLRs protein expressions and their association with clinical status and plasma markers in TB, HIV, and TB/HIV coinfection. The phenotyping of TLR2, TLR4, and TLR9 on CD14+ monocytes and their subsets were determined by multicolor flow cytometry. Host plasma biomarkers and microbial indices were measured using Luminex Multiplex assay and standard of care tools, respectively. TLR2 expression significantly enhanced in TB, slightly increased in HIV but slightly reduced in TB/HIV coinfection compared to apparently health controls (HC). On the other hand, TLR4 expression was significantly increased in TB, HIV, and TB/HIV compared to HC. Expression of TLR4 was equally enhanced on classical and intermediate monocytes while higher TLR2 expression on intermediate than classical monocytes. TLR4 had a positive correlation pattern with plasma biomarkers while TLR2 had an inverse correlation pattern. TLR4 is associated with disease severity while TLR2 is with the immune-competent status of patients. Our findings demonstrated that the pattern of TLR expression is disease as well as monocyte subset specific and distinct factors drive these differences.

Clinical and Imaging Characteristics of Smear Negative Pulmonary Tuberculosis Patients: A Comparative Study.

Background: Prevalence surveys in Ethiopia indicate smear negative pulmonary tuberculosis (SNPTB) taking the major share of the overall TB burden. It has also been a diagnostic dilemma worldwide leading to diagnostic delays and difficulty in monitoring treatment outcomes. This study determines and compares the clinical and imaging findings in SNPTB and smear positive PTB (SPPTB). Methodology. A case-control study was conducted on 313 PTB (173 SNPTB) patients. Data and sputum samples were collected from consented patients. Smear microscopy, GeneXpert, and culture analyses were performed on sputum samples. Data were analyzed using Stata version 17; a P value < 0.05 was considered statistically significant. Results: Of the 173 SNPTB patients, 42% were culture positive with discordances between test results reported by health facilities and Armauer Hansen Research Institute laboratory using concentrated smear microscopy. A previous history of TB and fewer cavitary lesions were significantly associated with SNPTB. Conclusions: Though overall clinical presentations of SNPTB patients resemble those seen in SPPTB patients, a prior history of TB was strongly associated with SNPTB. Subject to further investigations, the relatively higher discrepancies seen in TB diagnoses reflect the posed diagnostic challenges in SNPTB patients, as a higher proportion of these patients are also seen in Ethiopia.

Correction: Evaluation of the diagnostic performance of PanbioTM Abbott SARS-CoV-2 rapid antigen test for the detection of COVID-19 from suspects attending ALERT center.

[This corrects the article DOI: 10.1371/journal.pone.0277779.].

The Ethiopian National Immunization Technical Advisory Group (E-NITAG): Establishment, Achievements and the Future.

The National Immunization Program (NIP) was introduced in Ethiopia in 1980. The NIP has expanded the number of vaccines from six to more than 14 in 2023. However, decisions on new vaccine introduction and other vaccine-related matters were not systematically deliberated nationally. Thus, the need to establish a national body to deliberate on vaccine and vaccination matters, in addition to the global immunization advisory groups, has been emphasized in the last decade. This article presents the establishment and achievements of the Ethiopian NITAG. The E-NITAG was established in 2016 and maintained its active role in providing recommendations for new vaccine introduction and improving the delivery of routine vaccines. The external assessment indicated the E-NITAG was highly functional and played a critical role in enhancing the vaccination practice in Ethiopia, especially during the COVID-19 pandemic. The absence of a dedicated secretariat staff was the major bottleneck to expanding the role of the E-NITAG beyond responding to MOH requests. The E-NITAG must be strengthened by establishing a secretariat that can eventually grow as an independent institution to address complex vaccine-related issues the NIP needs to address.

Rare Variable M. tuberculosis Antigens induce predominant Th17 responses in human infection.

CD4 T cells are essential for immunity to M. tuberculosis (Mtb), and emerging evidence indicates that IL-17-producing Th17 cells contribute to immunity to Mtb. While identifying protective T cell effector functions is important for TB vaccine design, T cell antigen specificity is also likely to be important. To identify antigens that induce protective immunity, we reasoned that as in other pathogens, effective immune recognition drives sequence diversity in individual Mtb antigens. We previously identified Mtb genes under evolutionary diversifying selection pressure whose products we term Rare Variable Mtb Antigens (RVMA). Here, in two distinct human cohorts with recent exposure to TB, we found that RVMA preferentially induce CD4 T cells that express RoRγt and produce IL-17, in contrast to 'classical' Mtb antigens that induce T cells that produce IFNγ. Our results suggest that RVMA can be valuable antigens in vaccines for those already infected with Mtb to amplify existing antigen-specific Th17 responses to prevent TB disease.

Parasitic infection may be associated with discordant responses to QuantiFERON and tuberculin skin test in apparently healthy children and adolescents in a tuberculosis endemic setting, Ethiopia.

BACKGROUND: M. tuberculosis remains one of the world's deadliest pathogens in part because of its ability to establish persistent, latent infections, which can later reactivate to cause disease. In regions of the globe where disease is endemic, as much as 50% of the population is thought to be latently infected, complicating diagnosis and tuberculosis control. The tools most commonly used for diagnosis of latent M. tuberculosis infection are the tuberculin skin test and the newer interferon-gamma release assays, both of which rely on an antigen-specific memory response as an indicator of infection. It is clear that the two tests, do not always give concordant results, but the factors leading to this are only partially understood. METHODS: In this study we examined 245 healthy school children aged from 12 to 20 years from Addis Ababa, a tuberculosis-endemic region, characterised them with regard to response in the tuberculin skin test and QuantIFERON™ test and assessed factors that might contribute to discordant responses. RESULTS: Although concordance between the tests was generally fair (90% concordance), there was a subset of children who had a positive QuantIFERON™ result but a negative tuberculin skin test. After analysis of multiple parameters the data suggest that discordance was most strongly associated with the presence of parasites in the stool. CONCLUSIONS: Parasitic gut infections are frequent in most regions where M. tuberculosis is endemic. This study, while preliminary, suggests that the tuberculin skin test should be interpreted with caution where this may be the case.