Tolossa Chaka

Dr. Tolossa Chaka

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Research Focus & Metrics

Academic Career Length

10Years (2017-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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9 June 2020 in Scientific Reports
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MAMusa Mohammed Ali
Musa Mohammed Ali
DADaniel Asrat
Daniel Asrat
DFDemissie Assegu Fenta
Demissie Assegu Fenta
TCTolossa Chaka
Tolossa Chaka
YWYimtubezinash Woldeamanuel
Yimtubezinash Woldeamanuel
Rectovaginal area of pregnant women can be colonized transiently with group B Streptococcus (GBS) without causing disease. The bacteria can be transmitted to the newborn before and during birth and cause early-onset neonatal disease. In this study, we aimed to determine the GBS colonization rate among pregnant women before delivery and their newborns and serotypes distribution of GBS. Two hundred-eighty pregnant women along with their newborns were screened for GBS colonization from June 2014 to October 2014 at Adama Hospital Medical College. Rectovaginal swabs from pregnant women before delivery and specimen from nasal area, external ear, umbilical cord and throat of newborns were collected and cultured. The serotyping of GBS was performed by using serotype-specific antisera. To collect sociodemographic and clinical data we employed a structured questionnaire. GBS colonization among pregnant women and their newborns were 13.2% 95% CI (8.9–17.5) and 7.4% 95% CI (4.6–10.6). Out of 37 GBS strains recovered from pregnant women, the prevalent serotypes were Ia 6(16.2%), Ib 8(21.6%), II 10(27%), III 3(8.1%), and V 8(21.6%). Out of 21 GBS strains recovered from newborns, prevalent serotypes were Ia 3(14.3%), Ib 6(28.6%), II 6(28.6%), III 4(19%), and V 1(4.8%). This study indicated the existence of primary risk factors for neonatal disease in Adama area. Serotype II was the common serotype detected in this study which is followed by serotype Ib, Ia, and V. As colonizing GBS serotypes could cause invasive disease among newborns, vaccine formulation which includes serotype II, Ia, V, Ib, and III can prevent of invasive disease caused by GBS in the study area.

28 March 2019 in Journal of Clinical Medicine
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BTBirkneh Tilahun Tadesse
Birkneh Tilahun Tadesse
BFByron Alexander Foster
Byron Alexander Foster
AWAdugna Wari
Adugna Wari
TCTolossa Chaka
Tolossa Chaka
TBtemesgen bizuayehu
temesgen bizuayehu
EAEleni Aklillu
Eleni Aklillu
Background: Persistent dyslipidemia in children is associated with risks of cardiovascular accidents and poor combination antiretroviral therapy (cART) outcome. We report on the first evaluation of prevalence and associations with dyslipidemia due to HIV and cART among HIV-infected Ethiopian children. Methods: 105 cART naïve and 215 treatment experienced HIV-infected children were enrolled from nine HIV centers. Demographic and clinical data, lipid profile, cART type, adherence to and duration on cART were recorded. Total, low density (LDLc) and high density (HDLc) cholesterol values >200 mg/dL, >130 mg/dL, 150 mg/dL defined cases of dyslipidemia. Prevalence and predictors of dyslipidemia were compared between the two groups. Results: prevalence of dyslipidemia was significantly higher among cART experienced (70.2%) than treatment naïve (58.1%) children (p = 0.03). Prevalence of low HDLc (40.2% versus 23.4%, p = 0.006) and hypertriglyceridemia (47.2% versus 35.8%, p = 0.02) was higher among cART experienced than naïve children. There was no difference in total hypercholesterolemia and high LDLc levels. Nutrition state was associated with dyslipidemia among cART naïve children (p = 0.01). Conclusion: high prevalence of cART-associated dyslipidemia, particularly low HDLc and hypertriglyceridemia was observed among treatment experienced HIV-infected children. The findings underscore the need for regular follow up of children on cART for lipid abnormalities.

1 April 2019 in HIV/AIDS - Research and Palliative Care
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TCTolossa Chaka
Tolossa Chaka
TATilaye Workneh Abebe
Tilaye Workneh Abebe
RKRoza Kassa
Roza Kassa
Background: Vertical HIV transmission from mother-to-child accounts for more than 90% of pediatric HIV/AIDS infection. Virtual elimination of mother-to-child transmission (MTCT) of HIV is possible by giving comprehensive prevention of HIV/AIDS mother-to-child transmission (PMTCT) care. The objective of this study was to assess Option B+ (initiation of antiretroviral therapy for all pregnant mothers) PMTCT service intervention and outcomes in selected health facilities of Adama town, Ethiopia. Methods: A retrospective study was employed. A total of 248 medical records of mother–infant cohorts were included. Data wer collected from logbooks and/or records and individual medical records using a data abstraction tool. Results: Mean±SD age of mothers was 26.8±4.3 years. Half (50.8%) of the mothers were enrolled in PMTCT at 13–24 weeks of gestational age. The majority (79.6%) of mothers’ CD4 counts were ≥351/mm3,. Most of the mothers (71%) were on a tenofovir–lamivudine–evafrenz regimen. One-quarter of mothers were prescribed co-trimoxazole prophylactic therapy. Loss to follow-up from the Option B+ continuum was 10 (4.2%). Almost all (98.4%) of the infants were prescribed nevirapine prophylaxis. Nearly 90% (n=223) of the HIV-exposed infants were discharged as HIV negative. Conclusions: The Option B+ PMTCT service can minimize the chances of MTCT of HIV infection if used optimally. The magnitudes of loss to follow-up and death were lower than in comparable studies. Initiating all pregnant mothers on antiretroviral therapy irrespective of their clinical stage and CD4 count may have contributed to the optimal retention in care and near elimination of MTCT of HIV infection.

19 September 2019 in Viruses
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BTBirkneh Tilahun Tadesse
Birkneh Tilahun Tadesse
OTOlivia Tsai
Olivia Tsai
AWAdugna Wari
Adugna Wari
TCTolossa Chaka
Tolossa Chaka
TETemesgen Eromo
Temesgen Eromo
CBChanson J Brumme
Chanson J Brumme
Pediatric human immunodeficiency virus (HIV) care in resource-limited settings remains a major challenge to achieving global HIV treatment and virologic suppression targets, in part because the administration of combination antiretroviral therapies (cART) is inherently complex in this population and because viral load and drug resistance genotyping are not routinely available in these settings. Children may also be at elevated risk of transmission of drug-resistant HIV as a result of suboptimal antiretroviral administration for prevention of mother-to-child transmission. We investigated the prevalence and the correlates of pretreatment HIV drug resistance (PDR) among HIV-infected, cART-naive children in Ethiopia. We observed an overall PDR rate of 14%, where all cases featured resistance to non-nucleoside reverse transcriptase inhibitors (NNRTIs): ~9% of participants harbored resistance solely to NNRTIs while ~5% harbored resistance to both NNRTIs and nucleoside reverse transcriptase inhibitors (NRTIs). No resistance to protease inhibitors was observed. No sociodemographic or clinical parameters were significantly associated with PDR, though limited statistical power is noted. The relatively high (14%) rate of NNRTI resistance in cART-naive children supports the use of non-NNRTI-based regimens in first-line pediatric treatment in Ethiopia and underscores the urgent need for access to additional antiretroviral classes in resource-limited settings.

24 September 2019 in Pathogens
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BTBirkneh Tilahun Tadesse
Birkneh Tilahun Tadesse
AWAdugna Wari
Adugna Wari
JMJackson K. Mukonzo
Jackson K. Mukonzo
TCTolossa Chaka
Tolossa Chaka
STSintayehu Tadesse
Sintayehu Tadesse
EAEleni Aklillu
Eleni Aklillu
There is limited data on virologic outcome and its correlates among HIV-infected children in resource-limited settings. We investigated rate and correlates of virologic outcome among treatment naïve HIV-infected Ethiopian children initiating cART, and were followed prospectively at baseline, 8, 12, 24 and 48 weeks using plasma viral load, clinical examination, laboratory tests and pretreatment HIV drug resistance (PDR) screening. Virologic outcome was assessed using two endpoints–virological suppression defined as having “undetectable” plasma viral load < 150 RNA copies/mL, and rebound defined as viral load ≥150 copies/mL after achieving suppression. Cox Proportional Hazards Regression was employed to assess correlates of outcome. At the end of follow up, virologic outcome was measured for 110 participants. Overall, 94(85.5%) achieved virological suppression, of which 36(38.3%) experienced virologic rebound. At 48 weeks, 9(8.2%) children developed WHO-defined virological treatment failure. Taking tenofovir-containing regimen (Hazard Ratio (HR) 3.1-[95% confidence interval (95%CI) 1.0–9.6], p = 0.049) and absence of pretreatment HIV drug resistance (HR 11.7-[95%CI 1.3–104.2], p = 0.028) were independently associated with earlier virologic suppression. In conclusion, PDR and cART regimen type correlate with rate of virologic suppression which was prominent during the first year of cART initiation. However, the impact of viral rebound in 38.3% of the children needs evaluation.

Verified
Journal Article
Open access
PDF file
AWAdugna Wari
Adugna Wari
BTBirkneh Tilahun Tadesse
Birkneh Tilahun Tadesse
TCTolossa Chaka
Tolossa Chaka
JMJackson K. Mukonzo
Jackson K. Mukonzo
EKEliford Ngaimisi Kitabi
Eliford Ngaimisi Kitabi
EAEleni Aklillu
Eleni Aklillu
(1) Background: Efavirenz plasma concentration displays wide between-patient variability partly due to pharmacogenetic variation and autoinduction. Pediatric data on efavirenz pharmacokinetics and the relevance of pharmacogenetic variation are scarce, particularly from sub-Saharan Africa, where >90% of HIV-infected children live and population genetic diversity is extensive. We prospectively investigated the short- and long-term effects of efavirenz auto-induction on plasma drug exposure and the influence of pharmacogenetics among HIV-infected Ethiopian children. (2) Method: Treatment-naïve HIV-infected children aged 3–16 years old (n = 111) were enrolled prospectively to initiate efavirenz-based combination antiretroviral therapy (cART). Plasma efavirenz concentrations were quantified at 4, 8, 12, 24, and 48 weeks of cART. Genotyping for CYP2B6, CYP3A5, UGT2B7, ABCB1, and SLCO1B1 common functional variant alleles was performed. (3) Results: The efavirenz plasma concentration reached a peak at two months, declined by the 3rd month, and stabilized thereafter, with no significant difference in geometric mean over time. On average, one-fourth of the children had plasma efavirenz concentrations ≥4 µg/mL. On multivariate analysis, CYP2B6*6 and ABCB1c.3435 C > T genotypes and low pre-treatment low-density lipoprotein (LDL) were significantly associated with higher plasma efavirenz concentration regardless of treatment duration. Duration of cART, sex, age, nutritional status, weight, and SLCO1B, CYP3A5, UGT2B7, and ABCB1 rs3842 genotypes were not significant predictors of efavirenz plasma exposure. (4) Conclusion: Pre-treatment LDL cholesterol and CYP2B6*6 and ABCB1c.3435 C > T genotypes predict efavirenz plasma exposure among HIV-infected children, but treatment-duration-dependent changes in plasma efavirenz exposure due to auto-induction are not statistically significant.