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Dawit Wolday

Publications and source records attributed to Dawit Wolday.

At least 19 recordsLinked to original sources

Project ODIN: advancing environmental genomic surveillance for public health across sub-Saharan Africa.

Persistent SARS-CoV-2 transmission, ongoing mpox outbreaks, and the continued spread of endemic diseases such as typhoid fever and cholera underscore the urgent need for global, multiomics surveillance. In this Personal View, we present Project ODIN, a consortium of European and African partners launched in 2023 that aims to meet this challenge by deploying innovative systems for near real-time pathogen detection and actionable public health insights. The project is a collaboration between high-income and low-income countries in northern Europe and sub-Saharan Africa. Focusing on low-income and middle-income countries, ODIN integrates metagenomics with mobile laboratory systems for comprehensive pathogen monitoring across diverse environments. ODIN emphasises standardised sampling, bioinformatics pipelines, and data-sharing protocols to ensure reliable, interoperable results while addressing infrastructure and resource limitations. By bridging gaps in genomic surveillance, these initiatives seek to strengthen outbreak preparedness, improve pathogen detection, monitor antimicrobial resistance, and provide a holistic approach to One Health challenges. Together, these innovations could advance global surveillance capacity-particularly in under-resourced regions-paving the way for effective disease control and evidence-based policy making.

Humans↗

Reverse transcriptase activity for quantitation of HIV-1 subtype C in plasma: relation to RNA copy number and CD4 T-cell count.

The present study monitored the changes in human immunodeficiency virus (HIV) viral load using a reverse transcriptase (RT) assay and an HIV-1 RNA based assay, and relates these data to the dynamics of CD4 cell counts. The samples examined originate from a prospective study of HIV-1 subtype C infected, untreated Ethiopians followed twice yearly over a period of up to 5 years. The ExaVir Load test, version 1, was used for isolation and quantitation of HIV-1 RT in plasma. The RT activities recovered were compared to the HIV-1 RNA copy numbers, which had been determined previously by the NucliSens HIV-1 QT Test. There was a significant correlation between the data obtained in the two tests (r = 0.65, P < 0.0001). During follow-up, the median RT and RNA levels increased more or less in parallel up to approximately four times the values at admittance. CD4 cell counts, which had also been determined previously, decreased slowly but continuously from approximately 310 to 190 CD4 cells/ml. In the majority of individual patients, there was an inverse correlation between CD4 T-cell counts and RT activity, and with the RNA copy number, and the data obtained by either test could be used to predict CD4 T-cell counts. The ExaVir Load test thus provides data equivalent to the estimation of the number of HIV-1 RNA copies for the prediction of CD4 T-cell counts. It is based on a simple technique, can be run in any routine diagnostic laboratory, and is a competitive alternative for use in resource limited settings.

CD4 Lymphocyte Count↗

Tuberculin skin test conversion and reactivity rates among adults with and without human immunodeficiency virus in urban settings in Ethiopia.

To investigate whether low CD4+ T-cell counts in healthy and human immunodeficiency virus (HIV)-infected Ethiopians influence tuberculosis (TB) immunological memory, tuberculin skin test (TST) conversion and reactivity rates were investigated among adults with and without HIV infection in urban settings in Ethiopia. Reaction to the TST was analyzed with purified protein derivative by the Mantoux technique. A total of 1,286 individuals with TST results of > or = 5-mm (n = 851) and < or = 4-mm (n = 435) induration diameters were included. Individuals with < or = 4-mm induration sizes were followed up for 21.4 +/- 9.5 months (mean +/- standard deviation) to observe skin test conversion. The overall TST reactivity (> or = 5-mm induration diameter) was 66.2% (n = 851). Reactivity was significantly lower among HIV-positive persons (40.5%) than among HIV-negative persons (68.7%) (P < 0.001). Of the above persons, 32 incident TB patients were checked for their TST status 13.05 +/- 11.1 months before diagnosis and reactivity was found among 22 (68.7%) of them. Of the TST-negative persons with 0- to 4-mm indurations who were followed up for 3 years, the conversion rate to positivity was 17.9/100 person-years of observation (PYO) (14.4/100 PYO and 18.3/100 PYO in HIV-positive and -negative persons, respectively). Despite lower absolute CD4+ T-cell numbers in Ethiopians, higher TST conversion and reactivity rates show the presence of a higher rate of latent TB infection and/or transmission. The lower TST positivity rate before a diagnosis of TB disease showed the lower sensitivity of the test. This indicates the need for other sensitive and specific diagnostic and screening methods to detect TB infection, particularly among HIV-positive persons, so that they can be given prophylactic isoniazid therapy.

AIDS-Related Opportunistic Infections↗

Characterization of peripheral blood lymphocyte subsets in patients with acute Plasmodium falciparum and P. vivax malaria infections at Wonji Sugar Estate, Ethiopia.

We investigated the absolute counts of CD4+, CD8+, B, NK, and CD3+ cells and total lymphocytes in patients with acute Plasmodium falciparum and Plasmodium vivax malaria. Three-color flow cytometry was used for enumerating the immune cells. After slide smears were stained with 3% Giemsa stain, parasite species were detected using light microscopy. Data were analyzed using STATA and SPSS software. A total of 204 adults of both sexes (age, >15 years) were included in the study. One hundred fifty-eight were acute malaria patients, of whom 79 (50%) were infected with P. falciparum, 76 (48.1%) were infected with P. vivax, and 3 (1.9%) were infected with both malaria parasites. The remaining 46 subjects were healthy controls. The leukocyte count in P. falciparum patients was lower than that in controls (P=0.015). Absolute counts of CD4+, CD8+, B, and CD3+ cells and total lymphocytes were decreased very significantly during both P. falciparum (P<0.0001) and P. vivax (P<0.0001) infections. However, the NK cell count was an exception in that it was not affected by either P. falciparum or P. vivax malaria. No difference was found in the percentages of CD4, CD8, and CD3 cells in P. falciparum or P. vivax patients compared to controls. In summary, acute malaria infection causes a depletion of lymphocyte populations in the peripheral blood. Thus, special steps should be taken in dealing with malaria patients, including enumeration of peripheral lymphocyte cells for diagnostic purposes and research on peripheral blood to evaluate the immune status of patients.

Acute Disease↗

Intestinal microsporidiosis in diarrheal patients infected with human immunodeficiency virus-1 in Addis Ababa, Ethiopia.

Intestinal microsporidiosis is most commonly associated with persistent diarrhea in advanced AIDS cases. To determine the prevalence and clinical manifestations of this infection in HIV/AIDS patients, a single fresh stool sample and blood were collected from 243 (214 HIV-positive and 29 HIV-negative) diarrheal patients. The presence of intestinal microsporidiosis in the stool was determined by Uvitex-2B staining and a PCR-based detection method. HIV screening was done by using ELISA, and reactive samples were confirmed by Western blotting. The CD4+ cell count was analyzed using FACScan. Out of 243 diarrheal patients, 39 (16.0%) cases were positive for intestinal microsporidial infection by either of the methods used. Of the 39, only 18 cases positive by microscopy were also positive by PCR. Based on PCR and microscopic analyses the microsporidial parasites were identified as Enterocytozoon bieneusi (30), Ecephalitozoon intestinalis (6), and double infections (3). All microsporidia-positive cases were HIV-positive, and 92.3% had diarrhea for over 4 weeks. The diarrhea was watery in 79.5% of the patients. Weight loss >10% was recorded in 37 (94.9%) cases. The CD4+ cell count was <100 cells/mm(3) in 84.4% of subjects, and 59.4% of the patients had a CD4+ cell count of < or =50 cells/mm(3), with a mean of 22.8 cells/mm(3). This study revealed that intestinal microsporidiosis is a common cause of chronic diarrhea and severe weight loss in advanced AIDS patients in Ethiopia. This condition is attributable mainly to E. bieneusi. Thus, early diagnosis of intestinal microsporidiosis in HIV/AIDS patients would certainly be helpful in the understanding and management of diarrheal illness.

Adult↗

Kinetics of sedimentation rate, viral load and TNF-alpha in relation to HIV co-infection in tuberculosis.

The kinetics of potential surrogate markers in HIV-positive (HIV+) and HIV-negative (HIV-), smear-positive tuberculosis (Tb+) patients in Gondar, Ethiopia (n = 60) was investigated. Clinical symptoms, sputum conversion, sedimentation rate (SR), HIV viral load and serum levels of TNF-alpha were determined before and 8 weeks after treatment initiation. The co-infection rate of HIV was 45%. There were significantly higher initial levels of SR and TNF-alpha in HIV+/Tb+ patients (79 +/- 29 mm/h and 13.5 +/- 7.6 pg/ml), than in HIV-/Tb+ patients (60 +/- 23 mm/h and 6.8 +/- 5.9 pg/ml, P<0.001). In HIV-/Tb+ patients, there was a marked decrease in SR compared with co-infected patients (46% [33 +/- 24 mm/h at week 8] vs. 24% [61 +/- 27 mm/h at week 8]). The HIV viral load (4.99 [range 3.70-5.92] to 4.90 [range 3.96-5.78] log10 copies/ml from week 0 to 8) and TNF-alpha (13.5 +/- 7.6 to 12.0 +/- 6.0 pg/ml) remained high in HIV+/Tb+ patients. In Tb patients, SR was significantly increased in HIV+ compared with HIV- patients. Additionally, TNF-alpha and HIV viral load remained elevated in HIV+/Tb+ patients following treatment despite clinical improvement comparable to HIV-/Tb+ patients.

Adolescent↗

Surveillance technology for HIV-1 subtype C in Ethiopia: an env-based NASBA molecular beacon assay to discriminate between subcluster C and C'.

Forty-nine samples with known C2V3 sequences were used for the evaluation of an env-based molecular beacon assay to distinguish between the two genetic subclusters C and C' which characterize the HIV-1 epidemic in Ethiopia. Two subcluster C and two subcluster C' beacons targeting two different loci in the C2V3 region were developed. Using a three beacon-based (2C and 1C'=C prime), isothermal amplification assay, concordance with DNA sequencing was achieved for 43 (87.8%) samples. Sensitivity was 81.8% and specificity 97.4% for subcluster C beacons. For the subcluster C' beacon, a sensitivity of 97% and a specificity of 87.5% was achieved. Five samples were ambiguous by sequencing of which two samples were subcluster C' by the beacon assay and one subcluster C. Two of the samples remained ambiguous with different beacon-pair combinations as well. From samples with a clear C or C' phylogeny by sequencing, three were undetected by the first-line beacon genotyping assay. Genotype ambiguity was resolved in the three samples using beacon pair combinations restricted to each targeted locus. The beacons were evaluated further in a panel including all HIV-1 subtypes. Four of five subtype C isolates were identified correctly, and no cross-reactivity was observed with other subtypes.

Ethiopia↗

Low CD4 T cell counts before HIV-1 seroconversion do not affect disease progression in Ethiopian factory workers.

BACKGROUND: Human immunodeficiency virus type 1 (HIV-1)-uninfected Ethiopians have lower CD4 T cell counts than do other populations in Africa and industrialized countries. We studied whether this unique immunological profile results in shorter survival times in HIV-1-infected Ethiopians. METHODS: Data from an open cohort study of 149 HIV-1-infected factory workers in Ethiopia for 1997-2002 were used. To estimate survival times, a continuous-time Markov model was designed on the basis of CD4 T cell counts and World Health Organization clinical staging. By use of a random-effects model, decline in CD4 T cell counts was compared between HIV-1-infected Ethiopian and Dutch individuals. RESULTS: Median survival times were in the range of 9.1-13.7 years, depending on the approach used. This range is similar to that for populations in industrialized countries before the advent of antiretroviral therapy. Ethiopians had a lower annual decline in CD4 T cell counts than did Dutch individuals, which remained when groups with similar CD4 T cell count categories were compared. Moreover, the slower decline in CD4 T cell counts was not due merely to lower HIV-1 RNA loads or an absence of syncytium-inducing/X4 HIV-1 subtype C strains in Ethiopians. CONCLUSIONS: Low baseline CD4 T cell counts do not imply shorter survival times in Ethiopians than in other populations, presumably because of a slower decline in CD4 T cell counts.

Adult↗

Expression of chemokine receptors CCR5 and CXCR4 on CD4+ T cells and plasma chemokine levels during treatment of active tuberculosis in HIV-1-coinfected patients.

The pathogenesis of persistently elevated plasma HIV viremia in patients coinfected with tuberculosis (TB) during anti-TB treatment in Africans remains unknown. We examined the expression of chemokine receptors CCR5 and CXCR4 on CD4+ T cells and plasma chemokine levels of macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, regulated on activation normal T expressed and secreted (RANTES), and stromal cell-derived factor (SDF)-1alpha among TB patients with HIV coinfection during the first 2 months of anti-TB treatment. During treatment of TB, the plasma HIV-1 load and CD4+ T-cell count remained unchanged. Levels of CCR5 and CXCR4 expression on CD4+ T cells as well as plasma levels of chemokines remained persistently elevated during anti-TB treatment. Persistently elevated plasma HIV viremia also paralleled persistently elevated expressions of activated CCR5+ or CXCR4+ CD4+ T cells. These results suggest that increased expression of CCR5 and CXCR4 on an activated CD4+ T-cell population coupled with persistently elevated chemokines may provide a suitable condition for continuous replication of HIV associated with TB coinfection. This, in turn, may contribute, at least in part, to the observed persistently elevated plasma HIV viremia in coinfected patients despite anti-TB treatment.

AIDS-Related Opportunistic Infections↗

IL-8 increases transmission of HIV type 1 in cervical explant tissue.

Interleukin-8 (IL-8) is the predominant cytokine expressed in the female genital tract of women with certain infectious/inflammatory conditions. IL-8 increased HIV-1 replication in T cells and to a greater extent in monocytes/macrophages in vitro. Physiological levels of IL-8 increased susceptibility to HIV-1 infection 5- to 8-fold in cervical explant tissues. Competitive inhibition of the IL-8 receptor CXCR2 with the small molecule inhibitor SB225002 resulted in a 45-70% decrease in cervical explant susceptibility to HIV-1 infection.

Acquired Immunodeficiency Syndrome↗

Evidence of genetic variability of human immunodeficiency virus type 1 in plasma and cervicovaginal lavage in ethiopian women seeking care for sexually transmitted infections.

Most human immunodeficiency virus type 1 (HIV-1) transmission in developing countries occurs through heterosexual intercourse or during birth from mother to child. It is critical to characterize the virus of the genital tract variants as a target for the development of an HIV-1 vaccine and microbicidal therapies. We compared the C2V3 env domain genetic diversity of HIV-1 in female genital secretions and in plasma from Ethiopian women seeking care for sexually transmitted infections (STIs). Sequences within an individual differed between the plasma and cervicovaginal lavage (CLV) compartments with nucleotide and amino acid median difference values of 8.3 and 4.8%, respectively. Sequence diversity in CVL was greater than in plasma. And the V3 loop positive charge was often more elevated in CVL. These are markers of the differential evolution of the viruses in CVL and peripheral blood indicating that limited evolution at the site of contact is not the limiting factor determining the preferential transmission of macrophage tropic viruses.

Amino Acid Sequence↗

Alternative approach to blood screening using the ExaVir reverse transcriptase activity assay.

408 non-selected samples were obtained from healthy, adult individuals donating blood at the Ethiopian Red Cross Society-National Blood Transfusion Service. All samples were screened for HIV using the Vironostika Ag/Ab test, the Amplicor DNA PCR and examined for the presence of HIV reverse transcriptase (RT) using the ExaVir Load test (version 2). A panel of supplementary tests was used to evaluate the HIV status of the discordant samples and to confirm positivity. One aim was to assess an RT based test for screening for HIV in comparison with other more conventional tests. An HIV-prevalence of 3.4 % (14/408) was found. The Vironostika Ag/Ab test produced 391 negative, and according to the supplementary testing, 14 true- and three false- positive test results. The corresponding figures for the Amplicor DNA PCR test was 384 negative, 14 true- and two extra probably false -positive samples. In addition, the DNA PCR generated eight indeterminate results. The colorimetric version of the ExaVir load test exhibited 100 % specificity and detected RT in 13 of the true positive samples, but failed to detect one sample containing 200 HIV RNA copies /mL. This sample was detectable in the fluorimetric version of the test. The detection of RT activity in addition to the currently used markers would seem to have a potential for use in blood screening.

Blood Donors↗

Detection of intestinal microsporidiosis in diarrhoeal patients infected with the human immunideficiency virus (HIV-1) using PCR and Uvitex-2B stain.

A total of 105 single fresh stool samples were collected from diarrhoeal patients with (80 HIV-positive and 25 HIV-negative) from the Army and the Police hospitals, Addis Ababa. The stool samples were processed by water-ether sedimentation method; they were stained with Uvitex-2B technique for microscopic detection of intestinal microsporidium. A portion of all samples were preserved in 200microl PBS containing 2% PVPP ((Polyvinylpolypyrolidone) for confirmation with PCR. 18/105(17.2%) of the cases were positive for intestinal microsporidial infection by at least one method. 8/105 (7.6%) positive both by microscopy and PCR and 10/105 (9.5%) were positive only by PCR. All microsporidia positive cases were also HIV positive. Based on PCR analysis, 15 Enterocytozoon bieneusi and 3 Encephalitozoon intestinalis were identified. This study has shown that intestinal microsporidiosis is a common cause of chronic diarrhoea in advanced AIDS patients and this is mainly attributed to Enterocytozoon bieneusi. To the best of our knowledge, this is the first report of intestinal microsporidiosis in Ethiopia. It has an important implication for the understanding of the aetiology of diarrhoea in HIV/AIDS patients in the country.

AIDS-Related Opportunistic Infections↗

Prevalence and incidence of, and risk factors for, HIV-1 infection among factory workers in Ethiopia, 1997-2001.

The study was conducted to determine the prevalence, incidence, and risk factors for HIV infection among factory workers at two sites in Ethiopia. During February 1997-December 2001, a structured questionnaire was used for obtaining information on sociodemographics, sexual behaviour, and reported sexually transmitted infections (STIs) from a cohort of 1679 individuals. Serum samples were screened for antibodies against HIV, Treponema pallidum haemaglutination (TPHA), and herpes simplex virus type 2 (HSV-2). The overall baseline prevalence of HIV was 9.4%-8.5% among males and 12.4% among females. For both the sexes, the factors independently associated with an increased risk of HIV infection were widowhood and having had antibodies against TPHA and HSV-2. The risk factors specific for males were being orthodox Christian, having had a higher lifetime number of sexual partners, and genital discharge in the past five years. The risk factors for females, included low income, one or more rape(s) over lifetime, and casual sex in the last year. The overall incidence of HIV infection was 0.4 per 100 person-years. The highest rate of incidence was observed among young women aged less than 30 years (1 per 100 person-years). The study confirmed that high-risk sexual behaviour and STIs play major roles in the spread of HIV infection in the Ethiopians of both the sexes, but the factors, such as rape and low economic status, make women more vulnerable than men.

Adult↗

Transmission of herpes simplex virus Type 2 among factory workers in Ethiopia.

The herpes simplex virus type 2 (HSV-2) and human immunodeficiency virus (HIV) epidemics are believed to fuel each other, especially in sub-Saharan countries. In Ethiopia during 1997-2002, a retrospective study was conducted to examine risk factors for infection and transmission of HSV-2, in a cohort of 1612 factory workers. Prevalence of HSV-2 seropositivity at enrollment was 40.9%, and incidence of seroconversion was 1.8 seroconversions/100 person-years (PY), which decreased over time. Independent risk factors for seropositivity were having an HSV-2-seropositive partner, female sex, HIV antibodies, positive Treponema pallidum particle agglutination assay result, older age, low education level, and orthodox religion. These same factors were independent risk factors for HSV-2 seroconversion, with the exception of the latter 3. Most HSV-2-infected persons did not report symptoms. Among 41 monogamous HSV-2-serodiscordant heterosexual couples, incidence of HSV-2 seroconversion was 20.75 seroconversions/100 PY for women and 4.93 seroconversions/100 PY for men. The high burden of both HSV-2 and HIV infection in Ethiopia warrants stringent control measures.

Adult↗

The impact of syndromic treatment of sexually transmitted diseases on genital shedding of HIV-1.

OBJECTIVES: To examine the impact of sexually transmitted diseases (STD) syndromic treatment on genital shedding of HIV and the impact among women in whom STD treatment was not successful. DESIGN: Seventy-one HIV-infected women were included; 60 had symptomatic STD [72% with genital discharge syndrome (GDS) and 28% with genital ulcer syndrome (GUS)] and 11 controls did not have symptomatic STD. Cervical HIV load in 94% women was measured at baseline and after STD treatment. RESULTS: Cervical HIV load at entry was significantly higher in women with symptomatic STD than in controls [median, 3.15; interquartile range (IQR), 1.90-3.34 versus median, 1.90; IQR, 1.90-2.19 log10 RNA copies/swab, respectively; P = 0.024]. Women with STD were also more likely to have detectable cervical HIV RNA (68% versus 27%; P = 0.016). Cervical HIV load was significantly higher in women with GUS than in those with GDS (median 3.46; IQR, 2.84-4.18 versus median, 2.83; IQR, 1.90-3.31 log10 copies/swab; P = 0.019). There was no significant reduction in genital HIV shedding after syndromic treatment of GDS or GUS. However, significant decreases were limited to only those with clinical improvement (median, 2.91; IQR, 1.90-3.45 versus median, 2.25; IQR, 1.90-3.08 log10 RNA copies/swab, respectively; P = 0.006). GUS was significantly associated with treatment failure, independent of plasma HIV RNA load and CD4 T-cell count (odds ratio, 4.79; 95% confidence interval, 1.32-17.46). CONCLUSIONS: The fact that STD syndromic treatment impacts very little in reducing genital HIV shedding underscores the need for appropriate validation of STD syndromic diagnosis and management to control heterosexual transmission of HIV.

Adolescent↗

Development of a nucleic acid sequence-based amplification assay that uses gag-based molecular beacons to distinguish between human immunodeficiency virus type 1 subtype C and C' infections in Ethiopia.

A gag-based molecular beacon assay utilizing real-time nucleic acid sequence-based amplification technology has been developed to differentiate between the two genetic subclusters of human immunodeficiency virus type 1 (HIV-1) subtype C (C and C') circulating in Ethiopia. Of 41 samples, 36 could be classified as C or C' by sequencing of the gag gene. All 36 isolates were correctly identified by the gag beacon test. Three isolates with genomes that were recombinant in gag were unambiguously typed as belonging to the C' subcluster. Further analysis revealed that these contained the most sequence homology with a reference subcluster C' sequence in the target region of the beacon and hence were correct for the analyzed region. For one sample, sequencing and gag molecular beacon results did not match, while another isolate could not be detected at all by the beacon assay. Overall, high levels of sensitivity and specificity were achieved for both beacons (90.5% sensitivity and 100% specificity for the C beacon and 100% sensitivity and 95.2% specificity for the C' beacon). The availability of a diagnostic test which can quickly and reliably discriminate between C and C' HIV-1 infections in Ethiopia is an important first step toward studying their respective biological characteristics. As the assay is specific to the Ethiopian HIV-1 subtype C epidemic, it will contribute to characterizing the circulating viruses in this population, thereby generating the information necessary for the development of a potential efficacious HIV-1 vaccine appropriate for the Ethiopian context.

Base Sequence↗

Evaluation of rapid HIV test kits on whole blood and development of rapid testing algorithm for voluntary testing and counseling centers in Ethiopia.

Five simple and rapid HIV antibody detection assays viz. Determine, Capillus, Oraquick, Unigold and Hemastrip were evaluated to examine their performance and to develop an alternative rapid test based testing algorithm for voluntary counseling and testing (VCT) in Ethiopia. All the kits were tested on whole blood, plasma and serum. The evaluation had three phases: Primary lab review, piloting at point of service and implementation. This report includes the results of the first two phases. A total of 2,693 specimens (both whole blood and plasma) were included in the evaluation. Results were compared to double Enzyme Linked Immuno-Sorbent Assay (ELISA) system. Discordant EIA results were resolved using Western Blot. The assays had very good sensitivities and specificities, 99-100%, at the two different phases of the evaluation. A 98-100% result agreement was obtained from those tested at VCT centers and National Referral Laboratory for AIDS (NRLA), in the quality control phase of the evaluation. A testing strategy yielding 100% [95% CI; 98.9-100.0] sensitivity was achieved by the sequential use of the three rapid test kits. Direct cost comparison showed serial testing algorithm reduces the cost of testing by over 30% compared to parallel testing in the current situation. Determine, Capillus/Oraquick (presence/absence of frefrigeration) and Unigold were recommended as screening, confirmation and tiebreaker tests, respectively.

AIDS Serodiagnosis↗