Publications by authors named "Dawit Wolday"

Background: The ongoing emergence and spread of drug-resistant pathogens necessitate urgent solutions. Natural products from bacterial sources are recognized as a promising source of antibiotics. This study aimed to isolate and characterize soil microorganisms from extremely hot environments and to screen their secondary metabolites for antibacterial activity.

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Introduction: The GENCOV study sought to evaluate serological differences between individuals with differing COVID-19 severity and outcomes. We assessed the SARS-CoV-2 antibody response of GENCOV participants cross-sectionally 1-, 6-, and 12-months following COVID-19 diagnosis to identify patient factors associated with more robust and durable humoral immune responses.

Materials And Methods: COVID-19 patients and a control cohort of vaccinated infection-naïve participants were recruited at hospital sites across the Greater Toronto Area in Ontario, Canada.

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Hepatitis C virus (HCV) is hypothesised to be a public health problem in Ethiopia, and systematic review evidence suggested 1%-3% seroprevalence. We aimed to estimate the seroprevalence of HCV overall and across regions of Ethiopia. We estimated HCV seroprevalence using the 2016 Ethiopian Demographic and Health Survey (EDHS-2016).

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Introduction: Although wastewater-based epidemiology (WBE) successfully functioned as a tool for monitoring the coronavirus disease 2019 (COVID-19) pandemic globally, relatively little is known about its utility in low-income countries. This study aimed to quantify severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA in wastewater, estimate the number of infected individuals in the catchment areas, and correlate the results with the clinically reported COVID-19 cases in Addis Ababa, Ethiopia.

Methods: A total of 323 influent and 33 effluent wastewater samples were collected from three Wastewater Treatment Plants (WWTPs) using a 24-h composite Moore swab sampling method from February to November 2023.

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Unlabelled: Antimicrobial resistance is a growing global concern exacerbated by the scarcity of new medications and resistance to current antibiotics. Microbes from unexplored habitats are promising sources of natural products to combat this challenge. This study aimed to isolate bacteria producing secondary metabolites and assess their antimicrobial efficacy against human pathogens.

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In Ethiopia, dengue virus (DENV) infections have been reported in several regions, however, little is known about the circulating genetic diversity. Here, we conducted clinical surveillance for DENV during the 2023 nationwide outbreak and sequenced DENV whole genomes for the first time in Ethiopia. We enrolled patients at three sentinel hospital sites.

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Article Synopsis
  • - Ethiopia faces significant public health challenges due to the high prevalence of Hepatitis B virus (HBV) and its co-infections with hepatitis C virus (HCV) and HIV-1, particularly affecting vulnerable populations.
  • - A study analyzing 7,789 blood samples found that 815 were HBV positive, with a notable 67.30% showcasing mixed HBV genotypes A/E/F, alongside co-infection rates of 13.02% for HBV/HIV, 3.31% for HBV/HCV, and 2.07% for triple infections.
  • - The findings emphasize the need for targeted health interventions and improved patient care strategies to address the complexities of viral co-infections and curb ongoing
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Background: Diagnosis of visceral leishmaniasis (VL) in resource-limited endemic regions is currently based on serological testing with rK39 immunochromatographic tests (ICTs). However, rK39 ICT frequently has suboptimal diagnostic accuracy. Furthermore, treatment monitoring and detection of VL relapses is reliant on insensitive and highly invasive tissue aspirate microscopy.

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Background: GENCOV is a prospective, observational cohort study of COVID-19-positive adults. Here, we characterize and compare side effects between COVID-19 vaccines and determine whether reactogenicity is exacerbated by prior SARS-CoV-2 infection.

Methods: Participants were recruited across Ontario, Canada.

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The lack of accurate and feasible diagnostic tests poses a significant challenge to visceral leishmaniasis (VL) healthcare services in endemic areas. To date, various VL diagnostic tests have been or are being developed, and their diagnostic performances need to be assessed. In the present study, the diagnostic performances of rk39 RDT, the direct agglutination test (DAT), microscopy, loop-mediated isothermal amplification (LAMP), and miniature direct-on-blood polymerase chain reaction-nucleic acid lateral flow immunoassay (mini-dbPCR-NALFIA) were assessed using quantitative polymerase chain reaction (qPCR) as the reference test in an endemic region of Ethiopia.

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The GENCOV study aims to identify patient factors which affect COVID-19 severity and outcomes. Here, we aimed to evaluate patient characteristics, acute symptoms and their persistence, and associations with hospitalization. Participants were recruited at hospital sites across the Greater Toronto Area in Ontario, Canada.

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Purpose: To evaluate the role of C-reactive protein (CRP) in predicting severe COVID-19 patients.

Methods: A prospective observational cohort study was conducted from July 15 to October 28, 2020, at Kuyha COVID-19 isolation and treatment center hospital, Mekelle City, Northern Ethiopia. A total of 670 blood samples were collected serially.

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Differences in SARS-CoV-2-specific immune responses have been observed between individuals following natural infection or vaccination. In addition to already known factors, such as age, sex, COVID-19 severity, comorbidity, vaccination status, hybrid immunity, and duration of infection, inter-individual variations in SARS-CoV-2 immune responses may, in part, be explained by structural differences brought about by genetic variation in the human leukocyte antigen (HLA) molecules responsible for the presentation of SARS-CoV-2 antigens to T effector cells. While dendritic cells present peptides with HLA class I molecules to CD8+ T cells to induce cytotoxic T lymphocyte responses (CTLs), they present peptides with HLA class II molecules to T follicular helper cells to induce B cell differentiation followed by memory B cell and plasma cell maturation.

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Disseminated Strongloides stercoralis is a common phenomenon among patients with immunosuppression. In this report, we present a case of disseminated Strongloides stercoralis presenting as a gastric mass in a 42-year-old male patient with a known history of HIV-1 infection and type 2 diabetes mellitus (T2DM). The patient presented with symptoms and signs suggestive of acute on chronic erosive gastritis, which included persistent vomiting.

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Background: Serological testing for SARS-CoV-2 plays an important role for epidemiological studies, in aiding the diagnosis of COVID-19, and assess vaccine responses. Little is known on dynamics of SARS-CoV-2 serology in African settings. Here, we aimed to characterize the longitudinal antibody response profile to SARS-CoV-2 in Ethiopia.

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Background: Visceral Leishmaniasis (VL) is a severely neglected disease affecting millions of people with high mortality if left untreated. In Ethiopia, the primary laboratory diagnosis of VL is by using an antigen from a 39-amino acid sequence repeat of a kinesin-related (rK39) of leishmania donovani complex (L. donovani), rapid diagnostic tests (RDT).

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Background: The coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus (SARS-CoV-2) and became pandemic after emerging in Wuhan, China, in December 2019. Several studies have been conducted to understand the key features of COVID-19 and its public health impact. However, the prognostic factors of COVID-19 are not well studied in the African setting.

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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection results in a spectrum of clinical presentations. Evidence from Africa indicates that significantly less COVID-19 patients suffer from serious symptoms than in the industrialized world. We and others previously postulated a partial explanation for this phenomenon, being a different, more activated immune system due to parasite infections.

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Article Synopsis
  • The study assessed the effectiveness of a loop-mediated isothermal amplification (LAMP) assay for diagnosing visceral leishmaniasis (VL) in Ethiopia, showing a high sensitivity of 95.9% and specificity of 98.0%.
  • LAMP demonstrated strong performance against existing methods, detecting 94.3% of microscopy-positive cases and 94.2% of rK39-positive cases, with particularly high sensitivity in HIV-positive patients (100%).
  • Combining rK39 serology with LAMP could achieve a remarkable sensitivity of 99.2% and retains a specificity of 98.0%, showcasing LAMP as a rapid and reliable diagnostic option for VL, even in HIV co-in
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Chronic immune activation has been considered as the driving force for CD4 T cell depletion in people infected with HIV-1. Interestingly, the normal immune profile of adult HIV-negative individuals living in Africa also exhibit chronic immune activation, reminiscent of that observed in HIV-1 infected individuals. It is characterized by increased levels of soluble immune activation markers, such as the cytokines interleukin (IL)-4, IL-10, TNF-α, and cellular activation markers including HLA-DR, CD-38, CCR5, coupled with reduced naïve and increased memory cells in CD4 and CD8 subsets.

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Background: The rapid diagnostic test (RDT) rK39 is currently being used for routine diagnosis of visceral leishmaniasis (VL) in East Africa. However, continuous monitoring of the performance of the assay, in particular its impact on the clinical decision in initiating anti-leishmanial treatment and outcomes remains needed as there are concerns about the diagnostic performance of this test.

Methods: VL patients prospectively enrolled in a diagnostic trial and with rK39 RDT were included.

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