Biology subjects

Tsegaye, A. T.

Publications and source records attributed to Tsegaye, A. T..

4 recordsLinked to original sources

bioRxiv2025

Genital herpes shedding episodes associate with alterations in the spatial organization and activation of mucosal immune cells

Herpes Simplex Virus 2 (HSV-2) infection results in variable rates of local viral shedding in anogenital skin. The impact of episodic viral exposures on immune cells in adjacent mucosal tissues, including the genital tract, is unknown. However, any immune responses at this site could impact protective mucosal immunity, tissue homeostasis, and adverse health outcomes. To investigate the impact of HSV-2 on cervicovaginal tract immunity, we applied flow cytometry, immunofluorescent imaging, analysis of soluble immune factors, and spatial transcriptomics to cervicovaginal tissue and blood samples provided by a total of 232 HSV-2 seropositive and seronegative participants, with genital HSV-2 shedding evaluated at the time of biopsy. This unique dataset was used to define and spatially map immune cell subsets and localized gene expression via spatial transcriptomics. HSV-2 seropositivity alone was associated with minimal differences in cervicovaginal and circulating T cell phenotypes. However, the vaginal mucosa during active HSV-2 shedding was associated with alterations in T cell, macrophage, and dendritic cell localization and gene expression consistent with increased immune surveillance, with immune activating and suppressing signals potentially reinforcing mucosal tissue homeostasis. SummaryIn context of episodic HSV-2 shedding, immune cells mobilize and co-localize in the vaginal epithelium, expressing cytotoxic and inflammatory genes and immunoregulatory genes that collectively may promote tissue homeostasis in settings of episodic viral shedding to limit damage.

immunology↗

bioRxiv2024

Bacterial vaginosis-driven changes in vaginal T cell phenotypes and their implications for HIV susceptibility

Bacterial vaginosis (BV) is a dysbiosis of the vaginal microbiome that is prevalent among reproductive-age females worldwide. Adverse health outcomes associated with BV include an increased risk of sexually-acquired HIV, yet the immunological mechanisms underlying this association are not well understood. To investigate BV-driven changes to cervicovaginal tract (CVT) and circulating T cell phenotypes, participants with or without BV provided vaginal tract (VT) and ectocervical (CX) tissue biopsies and PBMC samples. High-parameter flow cytometry revealed an increased frequency of cervical conventional CD4+ T cells (Tconv) expressing CCR5. However, we found no difference in number of CD3+CD4+CCR5+ cells in the CX or VT of BV+ vs BV- individuals, suggesting that BV-driven increased HIV susceptibility may not be solely attributed to increased CVT HIV target cell abundance. Flow cytometry also revealed that individuals with BV have an increased frequency of dysfunctional CX and VT CD39+ Tconv and CX tissue-resident CD69+CD103+ Tconv, reported to be implicated in HIV acquisition risk and replication. Many soluble immune factor differences in the CVT further support that BV elicits diverse and complex CVT immune alterations. Our comprehensive analysis expands on potential immunological mechanisms that may underlie the adverse health outcomes associated with BV including increased HIV susceptibility.

immunology↗

bioRxiv2022

Population Structure and Ecology of the African elephant (Loxodonta africana, Blumenbach, 1797) in Chebera Churchura National Park, Ethiopia.

An investigation on population structure and ecology of the African elephants (Loxodonta africana) was carried out in Chebera Churchura National Park, Ethiopia during the wet and dry seasons of 2020 -2021. Sample counts using distance sampling of the African elephants were carried out in an area of 1, 410 km2. The total population estimated was 756 individuals, and the mean population density estimated was 0.53/km2. Among these, females constituted 52.12% and males 36.07%. The remaining 11.8% of the population was young of both sexes. It was difficult to categorize the young into male and female in the field, as their primary sexual characteristics were not easily visible. Male to female sex ratio was 1.00:-1.42. Age structure was dominated by adults, which constituted 53.83% of the total population. Sub-adults comprised 19.11%, juveniles contributed 15.18% and calves accounted for 12.11% of the population. The herd size ranged from 1 to 149 individuals and the mean herd size during wet and dry seasons were 16.5 and 50.25, respectively. The African elephants were distributed in four habitat types: grassland, woodland, montane forest and riverine habitats in the study area. They were observed more in the riverine vegetation types during the dry season. Relative abundance of food resources, green vegetation cover and water availability in the area were the major factors governing their distribution in the present study area.

ecology↗

bioRxiv2019

Incidence of mortality and its predictors among adult Visceral Leishmaniasis patients at University of Gondar Comprehensive Specialized Hospital, Ethiopia

BackgroundVisceral leishmaniasis (VL) is a neglected tropical disease resulting in a huge burden of mortality and impact on development of a country. Even though anti-leishmanial drugs reduce the incidence of mortality among VL patients, still there is a death of VL patients while on treatment. However, study on incidence of mortality and its predictors among these patients while on treatment is scarce in Ethiopia.\n\nObjectiveThe aim of this study was to determine incidence of mortality and its predictors among adult VL patients at University of Gondar Hospital.\n\nMethodsInstitution based retrospective follow up study was conducted from 2013 to 2018 at University of Gondar Hospital. Data were collected from patients chart and analyzed using Stata 14. Kaplan Meier failure curve and Log Rank test was used to compare survival probability of patients with categorical variables. Multivariable stratified Cox model was used to identify predictors of mortality among VL patients. P[≤] 0.05 was employed to declare statistically significant factors. Adjusted Hazard Ratio (AHR) and its 95% confidence interval (95% CI) was estimated for potential risk factors included in the multivariable model.\n\nResultsA total of 586 VL patients were included in the study. The median age of patients was 23 years. The incidence of mortality was 6.6 (95% CI: 5.2 - 8.4) per 1000 person-days of observation. Independent predictors of mortality were: presence of comorbidity (AHR=2.29 (95% CI: 1.27-4.11)), relapse VL (AHR=3.03 (95% CI: 1.25-7.35)), toxicity of treatment drug (AHR=5.87 (95% CI:3.30-10.44)), nasal bleeding (AHR=2.58 (95%CI: 1.48-4.51)), jaundice (AHR=2.84 (95% CI: 1.57-5.16)) and being bedridden (AHR=3.26 (95 % CI: 1.86-5.73)).\n\nConclusionThe incidence of mortality among VL patients was high. Mortality was higher among VL patients with concomitant disease, relapse, toxicity during treatment, nasal bleeding, jaundice, and bedridden patients. Therefore, strict follow up and treatment of VL patients who have comorbidity, relapse VL, toxicity, nasal bleeding and jaundice were crucial so as to reduce the risk of mortality.\n\nAuthors summaryVisceral leishmaniasis is a neglected tropical disease caused by a protozoa parasite. Over 90% of global burden of VL occurs in poor rural and suburban areas in seven countries including our country, Ethiopia. If not appropriately treated, over 95% of VL cases will eventually die. The emergence of VL in Ethiopia places a huge burden on society as it affects poor, young and productive age group of its population. However, there is scarcity of data about incidence of mortality and its predictors among adult VL patients in Ethiopia.\n\nIn this study, a registry of VL patients at Gondar University Hospital was taken to determine the incidence of VL mortality and its predictors. Mortality rate was higher among VL patients with concomitant disease, relapse, drug toxicity, nasal bleeding and jaundice. Therefore, strict follow up and treatment of VL patients who had comorbidity, relapse VL, drug toxicity, nasal bleeding and jaundice were crucial.

microbiology↗