Last data update: May 13, 2024. (Total: 46773 publications since 2009)
Records 1-10 (of 10 Records) |
Query Trace: Tsegaye T[original query] |
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Evidence for a role of Anopheles stephensi in the spread of drug and diagnosis-resistant malaria in Africa
Emiru T , Getachew D , Murphy M , Sedda L , Ejigu LA , Bulto MG , Byrne I , Demisse M , Abdo M , Chali W , Elliott A , Vickers EN , Aranda-Díaz A , Alemayehu L , Behaksera SW , Jebessa G , Dinka H , Tsegaye T , Teka H , Chibsa S , Mumba P , Girma S , Hwang J , Yoshimizu M , Sutcliffe A , Taffese HS , Bayissa GA , Zohdy S , Tongren JE , Drakeley C , Greenhouse B , Bousema T , Tadesse FG . Nat Med 2023 29 (12) 3203-3211 Anopheles stephensi, an Asian malaria vector, continues to expand across Africa. The vector is now firmly established in urban settings in the Horn of Africa. Its presence in areas where malaria resurged suggested a possible role in causing malaria outbreaks. Here, using a prospective case-control design, we investigated the role of An. stephensi in transmission following a malaria outbreak in Dire Dawa, Ethiopia in April-July 2022. Screening contacts of patients with malaria and febrile controls revealed spatial clustering of Plasmodium falciparum infections around patients with malaria in strong association with the presence of An. stephensi in the household vicinity. Plasmodium sporozoites were detected in these mosquitoes. This outbreak involved clonal propagation of parasites with molecular signatures of artemisinin and diagnostic resistance. To our knowledge, this study provides the strongest evidence so far for a role of An. stephensi in driving an urban malaria outbreak in Africa, highlighting the major public health threat posed by this fast-spreading mosquito. |
Anopheles stephensi Mosquitoes as Vectors of Plasmodium vivax and falciparum, Horn of Africa, 2019
Tadesse FG , Ashine T , Teka H , Esayas E , Messenger LA , Chali W , Meerstein-Kessel L , Walker T , Wolde Behaksra S , Lanke K , Heutink R , Jeffries CL , Mekonnen DA , Hailemeskel E , Tebeje SK , Tafesse T , Gashaw A , Tsegaye T , Emiru T , Simon K , Bogale EA , Yohannes G , Kedir S , Shumie G , Sabir SA , Mumba P , Dengela D , Kolaczinski JH , Wilson A , Churcher TS , Chibsa S , Murphy M , Balkew M , Irish S , Drakeley C , Gadisa E , Bousema T . Emerg Infect Dis 2021 27 (2) 603-607 Anopheles stephensi mosquitoes, efficient vectors in parts of Asia and Africa, were found in 75.3% of water sources surveyed and contributed to 80.9% of wild-caught Anopheles mosquitoes in Awash Sebat Kilo, Ethiopia. High susceptibility of these mosquitoes to Plasmodium falciparum and vivax infection presents a challenge for malaria control in the Horn of Africa. |
Bacteriologically-confirmed pulmonary tuberculosis in an Ethiopian prison: Prevalence from screening of entrant and resident prisoners
Tsegaye Sahle E , Blumenthal J , Jain S , Sun S , Young J , Manyazewal T , Woldeamanuel H , Teferra L , Feleke B , Vandenberg O , Rey Z , Briggs-Hagen M , Haubrich R , Amogne W , McCutchan JA . PLoS One 2019 14 (12) e0226160 BACKGROUND: Pulmonary Tuberculosis (PTB) is a major health problem in prisons. Multiple studies of TB in regional Ethiopian prisons have assessed prevalence and risk factors but have not examined recently implemented screening programs for TB in prisons. This study compares bacteriologically-confirmed PTB (BC-PTB) prevalence in prison entrants versus residents and identifies risk factors for PTB in Kality prison, a large federal Ethiopian prison located in Addis Ababa, through a study of an enhanced TB screening program. METHODS: Participating prisoners (n = 13,803) consisted of 8,228 entrants screened continuously and 5,575 residents screened in two cross-sectional waves for PTB symptoms, demographics, TB risk factors, and medical history. Participants reporting at least one symptom of PTB were asked to produce sputum which was examined by microscopy for acid-fast bacilli, Xpert MTB/RIF assay and MGIT liquid culture. Prevalence of BC-PTB, defined as evidence of Mycobacterium tuberculosis (MTB) in sputum by the above methods, was compared in entrants and residents for the study. Descriptive analysis of prevalence was followed by bivariate and multivariate analyses of risk factors. RESULTS: Prisoners were mainly male (86%), young (median age 26 years) and literate (89%). Prevalence of TB symptoms by screening was 17% (2,334/13,803) with rates in residents >5-fold higher than entrants. Prevalence of BC-PTB detected by screening in participating prisoners was 0.16% (22/13,803). Prevalence in residents increased in the second resident screening compared to the first (R1 = 0.10% and R2 = 0.39%, p = 0.027), but remained higher than in entrants (4.3-fold higher during R1 and 3.1-fold higher during R2). Drug resistance (DR) was found in 38% (5/13) of culture-isolated MTB. Risk factors including being ever diagnosed with TB, history of TB contact and low Body Mass Index (BMI) (<18.5) were significantly associated with BC-PTB (p<0.05). CONCLUSIONS: BC-PTB prevalence was strikingly lower than previously reported from other Ethiopian prisons. PTB appears to be transmitted within this prison based on its higher prevalence in residents than in entrants. Whether a sustained program of PTB screening of entrants and/or residents reduces prevalence of PTB in prisons is not clear from this study, but our findings suggest that resources should be prioritized to resident, rather than entrant, screening due to higher BC-PTB prevalence. Detection of multi- and mono-DR TB in both entrant and resident prisoners warrants regular screening for active TB and adoption of methods to detect drug resistance. |
Glucose-6-phosphate dehydrogenase (G6PD) deficiency in Ethiopia: absence of common African and Mediterranean allelic variants in a nationwide study
Assefa A , Ali A , Deressa W , Tsegaye W , Abebe G , Sime H , Kebede A , Jima D , Kassa M , Abreha T , Teka H , Solomon H , Malone J , Shi YP , Zhou Z , Reithinger R , Hwang J . Malar J 2018 17 (1) 388 BACKGROUND: Building on the declining trend of malaria in Ethiopia, the Federal Ministry of Health aims to eliminate malaria by 2030. As Plasmodium falciparum and Plasmodium vivax are co-endemic in Ethiopia, the use of primaquine is indicated for both transmission interruption and radical cure, respectively. However, the limited knowledge of the local prevalence of glucose-6-phosphate dehydrogenase (G6PD) deficiency and its associated variants has hindered the use of primaquine. METHODS: Some 11,138 dried blood spot (DBS) samples were collected in 2011 as part of a national, household Malaria Indicator Survey, a multi-stage nationally representative survey of all malaria-endemic areas of Ethiopia. A randomly selected sub-set of 1414 DBS samples was successfully genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. Considering the geographical position and ethnic mix of the country, three common variants: G6PD*A (A376G), G6PD*A- (G202A) and Mediterranean (C563T) were investigated. RESULTS: Of the 1998 randomly selected individuals, 1429 (71.5%) DBS samples were genotyped and merged to the database, of which 53.5% were from females. G6PD*A (A376G) was the only genotype detected. No sample was positive for either G6PD*A- (G202A) or Mediterranean (C563T) variants. The prevalence of G6PD*A (A376G) was 8.9% [95% confidence interval (CI) 6.7-11.2] ranging from 12.2% in the Southern Nations, Nationalities and Peoples' (95% CI 5.7-18.7) to none in Dire Dawa/Harari Region. CONCLUSION: The common G6PD*A- (G202A) or Mediterranean (C563T) variants were not observed in this nationwide study. The observed G6PD*A (A376G) mutation has little or no clinical significance. These findings supported the adoption of primaquine for P. falciparum transmission interruption and radical cure of P. vivax in Ethiopia. As the presence of other clinically important, less common variants cannot be ruled out, the implementation of radical cure will be accompanied by active haematological and adverse events monitoring in Ethiopia. |
Sero-prevalence of yellow fever and related Flavi viruses in Ethiopia: a public health perspective
Mengesha Tsegaye M , Beyene B , Ayele W , Abebe A , Tareke I , Sall A , Yactayo S , Shibeshi ME , Staples E , Belay D , Lilay A , Alemu A , Alemu E , Kume A , HMariam A , Ronveaux O , Tefera M , Kassa W , Bekele Weyessa A , Jima D , Kebede A , Tayachew A . BMC Public Health 2018 18 (1) 1011 BACKGROUND: Yellow fever (YF) is a viral hemorrhagic fever, endemic in the tropical forests of Africa and Central and South America. The disease is transmitted by mosquitoes infected with the yellow fever virus (YFV). Ethiopia was affected by the largest YF outbreak since the vaccination era during 1960-1962. The recent YF outbreak occurred in 2013 in Southern part of the country. The current survey of was carried out to determine the YF seroprevalence so as to make recommendations from YF prevention and control in Ethiopia. METHODOLOGY: A multistage cluster design was utilized. Consequently, the country was divided into 5 ecological zones and two sampling towns were picked per zone randomly. A total of 1643 serum samples were collected from human participants. The serum samples were tested for IgG antibody against YFV using ELISA. Any serum sample testing positive by ELISA was confirmed by plaque reduction neutralization test (PRNT). In addition, differential testing was performed for other flaviviruses, namely dengue, Zika and West Nile viruses. RESULT: Of the total samples tested, 10 (0.61%) were confirmed to be IgG positive against YFV and confirmed with PRNT. Nine (0.5%) samples were antibody positive for dengue virus, 15(0.9%) forWest Nile virus and 7 (0.4%) for Zika virus by PRNT. Three out of the five ecological zones namely zones 1, 3 and 5 showed low levels (< 2%) of IgG positivity against YFV. A total of 41(2.5%) cases were confirmed to be positive for one of flaviviruses tested. CONCLUSION: Based on the seroprevalence data, the level of YFV activity and the risk of a YF epidemic in Ethiopia are low. However additional factors that could impact the likelihood of such an epidemic occurring should be considered before making final recommendations for YF prevention and control in Ethiopia. Based on the results of the serosurvey and other YF epidemic risk factors considered, a preventive mass vaccination campaign is not recommended, however the introduction of YF vaccine in routine EPI is proposed nationwide, along with strong laboratory based YF surveillance. |
Early impact of rotavirus vaccine in under 5year old children hospitalized due to diarrhea, Swaziland
Maphalala G , Phungwayo N , Masona G , Lukhele N , Tsegaye G , Dube N , Sindisiwe D , Khumalo L , Daniel F , Katsande R , Tate JE , Mwenda JM , Weldegebriel G . Vaccine 2017 36 (47) 7210-7214 BACKGROUND: Swaziland introduced rotavirus vaccine in the National Immunization Program, in May 2015, with the objective of reducing the burden of rotavirus diarrheal disease. We monitored the early impact of the vaccine in reducing rotavirus diarrhea. METHODS: We conducted sentinel rotavirus surveillance from January 2013 to December 2016 in children under five years of age admitted due to diarrhea attending Mbabane Government Referral Hospital in the Hhohho Region and Raleigh Fitkin Memorial Hospital in the Manzini Region. All cases had stool samples collected and tested for rotavirus antigen by enzyme immunoassay. RESULTS: Between 2013 and 2016, 596 samples were collected and tested. Rotavirus positivity reduced from average of 50.8% (172/338) (in 2013-2014 (pre vaccine period)) to 29% (24/82) in 2016, post-vaccine introduction. The median age of children with rotavirus infection increased from average of 10months in 2013-2014 to 13.7months in 2016. The peak season for all-cause diarrhea and rotavirus-specific hospitalizations among children under five years of age was June-August in all years with a blunting of the peak season in 2016. Rotavirus positivity among children 0-11months reduced from an average of 49% in 2013-2014 (116/236) to 33% (15/45) in 2016, a 33% reduction following rotavirus vaccine introduction. CONCLUSION: There has been a rapid reduction of all-cause diarrhea and rotavirus hospitalizations in Swaziland, particularly in young children and during the rotavirus season, after the introduction rotavirus vaccine. Continued surveillance is needed to monitor the long-term impact of rotavirus vaccine introduction. |
Repeated vaginal SHIV challenges in macaques receiving oral or topical Pre-Exposure Prophylaxis induce virus-specific T cell responses
Tsegaye TS , Butler K , Luo W , Radzio J , Srinivasan P , Sharma S , Aubert RD , Hanson DL , Dobard C , Garcia-Lerma JG , Heneine W , McNicholl JM , Kersh EN . J Acquir Immune Defic Syndr 2015 69 (4) 385-94 BACKGROUND: Pre-Exposure Prophylaxis (PrEP) for HIV prevention is a novel biomedical prevention method. We have previously modeled PrEP during rectal SHIV exposures in macaques and identified that SHIV-specific T cell responses were induced in the presence of antiretroviral drugs, an observation previously termed T cell chemo-vaccination. This report expands those initial findings by examining a larger group of macaques that were given oral or topical PrEP during repeated vaginal virus exposure. METHODS: Thirty-six female pigtail macaques received up to 20 repeat low-dose vaginal inoculations with wild type (WT) SHIVSF162P3 (n=24) or a clonal derivative with the tenofovir K65R drug resistant mutation (n=12). PrEP consisted of oral Truvada (n=6, WT), tenofovir vaginal gel (n=6, K65R), or tenofovir intra-vaginal ring (n=6, WT). The remaining animals were PrEP-inexperienced controls (n=12, WT; n=6, K65R). SHIV-specific T cells were identified and characterized using IFNgamma ELISPOT and multi-parameter flow cytometry. RESULTS: Of nine animals that were on PrEP and remained uninfected during WT SHIV vaginal challenges, eight (88.9%) developed virus-specific T cell responses. T cells were in CD4 and CD8 compartments, reached up to 4,900 IFNgamma producing cells per million PBMCs, and primarily pol directed. In contrast, the replication impaired K65R virus did not induce detectable T cell responses, likely reflecting the need for adequate replication. CONCLUSION: Virus-specific T cell responses occur frequently in oral or topical PrEP-protected pigtail macaques after vaginal exposure to WT SHIV virus. The contribution of such immune responses to protection from infection during and following PrEP warrants further investigation. |
Rectal application of a highly osmolar personal lubricant in a macaque model induces acute cytotoxicity but does not increase risk of SHIV infection
Vishwanathan SA , Morris MR , Wolitski RJ , Luo W , Rose CE , Blau DM , Tsegaye T , Zaki SR , Garber DA , Jenkins LT , Henning TC , Patton DL , Hendry RM , McNicholl JM , Kersh EN . PLoS One 2015 10 (4) e0120021 BACKGROUND: Personal lubricant use is common during anal intercourse. Some water-based products with high osmolality and low pH can damage genital and rectal tissues, and the polymer polyquaternium 15 (PQ15) can enhance HIV replication in vitro. This has raised concerns that lubricants with such properties may increase STD/HIV infection risk, although in vivo evidence is scarce. We use a macaque model to evaluate rectal cytotoxicity and SHIV infection risk after use of a highly osmolar (>8,000 mOsm/kg) water-based lubricant with pH of 4.4, and containing PQ15. METHODS: Cytotoxicity was documented by measuring inflammatory cytokines and epithelial tissue sloughing during six weeks of repeated, non-traumatic lubricant or control buffer applications to rectum and anus. We measured susceptibility to SHIVSF162P3 infection by comparing virus doses needed for rectal infection in twenty-one macaques treated with lubricant or control buffer 30 minutes prior to virus exposure. RESULTS: Lubricant increased pro-inflammatory cytokines and tissue sloughing while control buffer (phosphate buffered saline; PBS) did not. However, the estimated AID50 (50% animal infectious dose) was not different in lubricant- and control buffer-treated macaques (p = 0.4467; logistic regression models). CONCLUSIONS: Although the test lubricant caused acute cytotoxicity in rectal tissues, it did not increase susceptibility to infection in this macaque model. Thus neither the lubricant-induced type/extent of inflammation nor the presence of PQ15 affected infection risk. This study constitutes a first step in the in vivo evaluation of lubricants with regards to HIV transmission. |
Lack of prophylactic efficacy of oral maraviroc in macaques despite high drug concentrations in rectal tissues
Massud I , Aung W , Martin A , Bachman S , Mitchell J , Aubert R , Tsegaye TS , Kersh E , Pau CP , Heneine W , Garcia-Lerma JG . J Virol 2013 87 (16) 8952-61 Maraviroc (MVC) is a potent CCR5 co-receptor antagonist that is in clinical testing for daily oral pre-exposure prophylaxis (PrEP) for HIV prevention. We used a macaque model consisting of weekly SHIV162p3 exposures to evaluate the efficacy of oral MVC in preventing rectal SHIV transmission. MVC dosing was informed by the pharmacokinetic profile seen in blood and rectal tissues, and consisted of a human-equivalent dose given 24h before virus exposure followed by a booster post-exposure dose. In rectal secretions, MVC peaked at 24h (10,242 ng/ml) with concentrations at 48h that were about 40 times those required to block SHIV infection of PBMCs in vitro. Median MVC concentrations in rectal tissues at 24h (1,404 ng/g) were 30 and 10 times those achieved in vaginal or lymphoid tissues, respectively. MVC significantly reduced MIP-1beta-induced CCR5 internalization in rectal mononuclear cells, an indication of efficient binding to CCR5 in rectal lymphocytes. The half-life of CCR5-bound MVC in PBMCs was 2.6 days. Despite this favorable profile, 5/6 treated macaques were infected during 5 rectal SHIV exposures as were 3/4 controls. MVC treatment was associated with a significant increase in the percentage of CD3+/CCR5+ cells in blood. We show that high and durable MVC concentrations in rectal tissues are not sufficient to prevent SHIV infection in macaques. The increases in CD3+/CCR5+ cells seen during MVC treatment point to unique immunological effects of CCR5 inhibition by MVC. The implications of these immunological effects on PrEP with MVC require further evaluation. |
Launch of the international podoconiosis initiative
Davey G , Bockarie M , Wanji S , Addiss D , Fuller C , Fox L , Mycoskie M , Gruin M , Tsegaye A , Ayele FT , Newport M . Lancet 2012 379 (9820) 1004 In the past 5 years, important progress in podoconiosis research and control has been made. The global distribution of this ascending, geochemical lymphoedema has been updated, advances have been made in disease assessment and treatment, and advocacy has successfully brought podoconiosis to the global stage. We highlight some of this progress here, and announce the launch of a new international initiative. | Wanji and colleagues1 and Ruberanziza and colleagues2 have shown elephantiasis in the absence of filarial parasites during mapping in Cameroon and Rwanda, respectively. A new staging system for podoconiosis has been developed and validated, and used to assess the simple treatment regimen developed by a patient-led and community-based control programme in southern Ethiopia.3 Ethical approaches to research in the remote communities in which podoconiosis patients are usually found have been developed,4 and issues related to community attitudes, quality of life, and stigma have been documented.5 Ongoing research in Ethiopia and Cameroon aims to identify the locus of a susceptibility gene and to characterise the minerals that trigger podoconiosis. Other studies are investigating immunological changes associated with podoconiosis, documenting overlaps with other common tropical diseases, and exploring behavioural issues that will be vital to understand as prevention programmes increase shoe distribution to high-risk children. |
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