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Yared S, Gebressilasie A, Worku A, Mohammed A, Gunarathna I, Rajamanickam D, Waymire E, Balkew M, Carter TE. Breeding habitats, bionomics and phylogenetic analysis of Aedes aegypti and first detection of Culiseta longiareolata, and Ae. hirsutus in Somali Region, eastern Ethiopia. PLoS One 2024; 19:e0296406. [PMID: 38165914 PMCID: PMC10760653 DOI: 10.1371/journal.pone.0296406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 12/12/2023] [Indexed: 01/04/2024] Open
Abstract
INTRODUCTION Arboviral diseases, such as dengue, chikungunya, yellow fever, and Zika, are caused by viruses that are transmitted to humans through mosquito bites. However, the status of arbovirus vectors in eastern Ethiopia is unknown. The aim of this study was to investigate distribution, breeding habitat, bionomics and phylogenetic relationship of Aedes aegypti mosquito species in Somali Regional State, Eastern Ethiopia. METHODS Entomological surveys were conducted in four sites including Jigjiga, Degehabur, Kebridehar and Godey in 2018 (October to December) to study the distribution of Ae. aegypti and with a follow-up collection in 2020 (July-December). In addition, an investigation into the seasonality and bionomics of Ae. aegypti was conducted in 2021 (January-April) in Kebridehar town. Adult mosquitoes were collected from indoor and outdoor locations using CDC light traps (LTs), pyrethrum spray collection (PSCs), and aspirators. Larvae and pupae were also collected from a total of 169 water-holding containers using a dipper between October and November 2020 (rainy season) in Kebridehar town. The species identification of wild caught and reared adults was conducted using a taxonomic key. In addition, species identification using mitochondrial and nuclear genes maximum likelihood-based phylogenetic analysis was performed. RESULTS In the 2018 collection, Ae. aegypti was found in all study sites (Jigjiga, Degahabour, Kebridehar and Godey). In the 2020-2021 collection, a total of 470 (Female = 341, Male = 129) wild caught adult Ae. aegypti mosquitoes were collected, mostly during the rainy season with the highest frequency in November (n = 177) while the lowest abundance was in the dry season (n = 14) for both February and March. The majority of Ae. aegypt were caught using PSC (n = 365) followed by CDC LT (n = 102) and least were collected by aspirator from an animal shelter (n = 3). Aedes aegypti larval density was highest in tires (0.97 larvae per dip) followed by cemented cisterns (0.73 larvae per dip) and the Relative Breeding Index (RBI) was 0.87 and Container Index (CI) was 0.56. Genetic analysis of ITS2 and COI revealed one and 18 haplotypes, respectively and phylogenetic analysis confirmed species identification. The 2022 collection revealed no Ae. aegpti, but two previously uncharacterized species to that region. Phylogenetic analysis of these two species revealed their identities as Ae. hirsutus and Culiseta longiareolata. CONCLUSION Data from our study indicate that, Ae. aegypti is present both during the wet and dry seasons due to the availability of breeding habitats, including water containers like cemented cisterns, tires, barrels, and plastic containers. This study emphasizes the necessity of establishing a national entomological surveillance program for Aedes in Somali region.
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Affiliation(s)
- Solomon Yared
- Department of Biology, Jigjiga University, Jigjiga, Ethiopia
| | - Araya Gebressilasie
- Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Amha Worku
- Department of Biology, Jigjiga University, Jigjiga, Ethiopia
| | - Abas Mohammed
- Department of Biology, Jigjiga University, Jigjiga, Ethiopia
| | - Isuru Gunarathna
- Department of Biology, College of Arts and Sciences, Baylor University, Waco, TX, United States of America
| | - Dhivya Rajamanickam
- Department of Biology, College of Arts and Sciences, Baylor University, Waco, TX, United States of America
| | - Elizabeth Waymire
- Department of Biology, College of Arts and Sciences, Baylor University, Waco, TX, United States of America
| | - Meshesha Balkew
- Abt Associates, PMI VectorLink Ethiopia Project, Addis Ababa, Ethiopia
| | - Tamar E. Carter
- Department of Biology, College of Arts and Sciences, Baylor University, Waco, TX, United States of America
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Yared S, Abera T, Ali SM, Muhummed AM, Ibrahim M, Hassan A, Hattendorf J, Zinsstag J, Tschopp R. A community based seroprevalence of SARS-CoV-2 antibodies in Somali Region, Eastern Ethiopia. Immun Inflamm Dis 2024; 12:e1148. [PMID: 38270297 PMCID: PMC10777752 DOI: 10.1002/iid3.1148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 12/25/2023] [Accepted: 12/28/2023] [Indexed: 01/26/2024] Open
Abstract
BACKGROUND Coronavirus disease 19 (COVID-19) is life-threatening infectious disease caused by SARS-CoV-2 virus that caused a global pandemic. SARS-CoV-2 has been widely transmitted throughout Ethiopia, with over 501,060 cases confirmed and 7574 deaths until November 2023. This study assessed for the first time the seroprevalence SARS-CoV-2 in the general population of the Somali Region during the COVID-19 pandemic. METHODS A cross-sectional study design was conducted from May to June 2021 in 14 districts of Somali Region. Blood samples were collected in 820 participants in addition to administering a questionnaire that included sociodemographic characteristics and history of clinical symptoms of COVID-19. Blood samples were tested for the presence or absence of anti-SARS-CoV-2 using a commercial Enzyme-Linked Immunosorbent Assay (ELISA) kit (Euroimmun). RESULTS Overall, 477 (58.2%) were male and 343 (41.8%) were female. The majority of the participants (N = 581; 70.9%) were between 18 and 34 years old and not vaccinated against COVID-19 (N = 793; 96.7%). The overall seroprevalence of SARS-CoV-2 antibodies was 41.7% (95% CI: 33.3%-47.6%). The highest prevalence was found in Goljano district (70%) and the lowest in Gunagado district (22.5%). Only age was found to be associated with COVID-19 seropositivity. CONCLUSION Prevalence of SARS-CoV-2 antibodies was the highest ever reported in Ethiopia, indicating that a large proportion of the population had been infected 14 months after the start of the outbreak in the country. Such studies are important to swiftly reassess and improve specific COVID-19 preventive and control measures to reduce transmissions within the community in a given setting.
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Affiliation(s)
- Solomon Yared
- Department of Biology, College of Natural and Computational SciencesJigjiga UniversityJigjigaEthiopia
| | - Tsegalem Abera
- Department of Veterinary Microbiology and Public Health, College of Veterinary MedicineJigjiga UniversityJigjigaEthiopia
| | - Seid Mohammed Ali
- Department of Animal and Range Sciences, College of Dryland AgricultureJigjiga UniversityJigjigaEthiopia
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health InstituteUniversity of BaselBaselSwitzerland
| | - Abdifatah Muktar Muhummed
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health InstituteUniversity of BaselBaselSwitzerland
- School of Medicine, College of Medicine and Health SciencesJigjiga UniversityJigjigaEthiopia
| | - Mohammed Ibrahim
- Department of Veterinary Microbiology and Public Health, College of Veterinary MedicineJigjiga UniversityJigjigaEthiopia
| | - Abdullahi Hassan
- School of Medicine, College of Medicine and Health SciencesJigjiga UniversityJigjigaEthiopia
| | - Jan Hattendorf
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health InstituteUniversity of BaselBaselSwitzerland
| | - Jakob Zinsstag
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health InstituteUniversity of BaselBaselSwitzerland
| | - Rea Tschopp
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health InstituteUniversity of BaselBaselSwitzerland
- One Health UnitArmauer Hansen Research InstituteAddis AbabaEthiopia
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Yared S, Gebresilassie A, Aklilu E, Abdulahi E, Kirstein OD, Gonzalez-Olvera G, Che-Mendoza A, Bibiano-Marin W, Waymire E, Lines J, Lenhart A, Kitron U, Carter T, Manrique-Saide P, Vazquez-Prokopec GM. Building the vector in: construction practices and the invasion and persistence of Anopheles stephensi in Jigjiga, Ethiopia. Lancet Planet Health 2023; 7:e999-e1005. [PMID: 38056970 DOI: 10.1016/s2542-5196(23)00250-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 10/26/2023] [Accepted: 10/30/2023] [Indexed: 12/08/2023]
Abstract
Anopheles stephensi is a major vector of malaria in Asia and the Arabian Peninsula, and its recent invasion into Africa poses a major threat to malaria control and elimination efforts on the continent. The mosquito is well adapted to urban environments, and its presence in Africa could potentially lead to an increase in malaria transmission in cities. Most of the knowledge about An stephensi ecology in Africa has been generated from studies conducted during the rainy season, when vectors are most abundant. Here, we provide evidence from the peak of the dry season in the city of Jigjiga in Ethiopia, and report An stephensi immature stages infesting predominantly in water reservoirs made to support construction operations (ie, in construction sites or associated with brick-manufacturing businesses). Political and economic changes in Ethiopia (particularly the Somali Region) have fuelled an unprecedented construction boom since 2018 that, in our opinion, has been instrumental in the establishment, persistence, and propagation of An stephensi via the year-round availability of perennial larval habitats associated with construction. We argue that larval source management during the dry season might provide a unique opportunity for focused control of An stephensi in Jigjiga and similar areas.
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Affiliation(s)
- Solomon Yared
- Department of Biology, Jigjiga University, Jigjiga, Ethiopia
| | - Araya Gebresilassie
- Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Esayas Aklilu
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
| | - Elyas Abdulahi
- Population, Resources and Environmental Economics, Jigjiga University, Jigjiga, Ethiopia
| | | | - Gabriela Gonzalez-Olvera
- Collaborative Unit for Entomological Bioassays, Autonomous University of Yucatan, Mérida, Mexico
| | - Azael Che-Mendoza
- Collaborative Unit for Entomological Bioassays, Autonomous University of Yucatan, Mérida, Mexico
| | - Wilbert Bibiano-Marin
- Collaborative Unit for Entomological Bioassays, Autonomous University of Yucatan, Mérida, Mexico
| | | | - Jo Lines
- London School of Public Health, London, UK
| | - Audrey Lenhart
- Entomology Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Uriel Kitron
- Department of Environmental Sciences, Emory University, Atlanta, GA, USA
| | - Tamar Carter
- Department of Biology, Baylor University, Wako, TX, USA
| | - Pablo Manrique-Saide
- Collaborative Unit for Entomological Bioassays, Autonomous University of Yucatan, Mérida, Mexico
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Gonzalez-Olvera G, Yared S, Aklilu E, Gebresilassie A, Bibiano-Marin W, Che-Mendoza A, Kirstein O, Vazquez-Prokopec GM, Manrique-Saide P. Laboratory Evaluation of Efficacy of the Larvicide Spinosad Against AnophelesStephensi in Jigjiga, Ethiopia. J Am Mosq Control Assoc 2023; 39:284-287. [PMID: 38078512 DOI: 10.2987/23-7141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
We report the efficacy of a commercial formulation of the insecticide spinosad against larvae of Anopheles stephensi populations found in the city of Jigjiga, Somali Region, eastern Ethiopia. Batches of 25 larvae (late III to early IV instars) collected from large water storage reservoirs associated with construction sites (the primary An. stephensi larval site in the dry season) were tested under laboratory conditions against each insecticide at a dose recommended by the manufacturer (Natular® G30, 0.02 g/5 liter), following World Health Organization guidelines. Mortality at 24-48 h postexposure was 100%. Results show that spinosad is effective against An. stephensi larvae and suggest that it may be a useful tool as part of larval source management plans aimed at controlling this invasive malaria vector in Ethiopia.
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Samake JN, Lavretsky P, Gunarathna I, Follis M, Brown JI, Ali S, Yared S, Carter TE. Population genomic analyses reveal population structure and major hubs of invasive Anopheles stephensi in the Horn of Africa. Mol Ecol 2023; 32:5695-5708. [PMID: 37795951 DOI: 10.1111/mec.17136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 08/15/2023] [Accepted: 09/04/2023] [Indexed: 10/06/2023]
Abstract
Anopheles stephensi invasion in the Horn of Africa (HoA) poses a substantial risk of increased malaria disease burden in the region. An understanding of the history of introduction(s), establishment(s) and potential A. stephensi sources in the HoA is needed to predict future expansions and establish where they may be effectively controlled. To this end, we take a landscape genomic approach to assess A. stephensi origins and spread throughout the HoA, information essential for vector control. Specifically, we assayed 2070 genome-wide single nucleotide polymorphisms across 214 samples spanning 13 populations of A. stephensi from Ethiopia and Somaliland collected in 2018 and 2020, respectively. Principal component and genetic ancestry analyses revealed clustering that followed an isolation-by-distance pattern, with genetic divergence among the Ethiopian samples significantly correlating with geographical distance. Additionally, genetic relatedness was observed between the northeastern and east central Ethiopian A. stephensi populations and the Somaliland A. stephensi populations. These results reveal population differentiation and genetic connectivity within HoA A. stephensi populations. Furthermore, based on genetic network analysis, we uncovered that Dire Dawa, the site of a spring 2022 malaria outbreak, was one of the major hubs from which sequential founder events occurred in the rest of the eastern Ethiopian region. These findings can be useful for the selection of sites for heightened control to prevent future malaria outbreaks. Finally, we did not detect significant genotype-environmental associations, potentially due to the recency of their colonization and/or other anthropogenic factors leading to the initial spread and establishment of A. stephensi. Our study highlights how coupling genomic data at landscape levels can shed light into even ongoing invasions.
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Affiliation(s)
| | - Philip Lavretsky
- Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, USA
| | | | - Madison Follis
- Department of Biology, Baylor University, Waco, Texas, USA
| | - Joshua I Brown
- Department of Life, Earth, and Environmental Sciences, West Texas A&M University, Canyon, Texas, USA
| | - Said Ali
- Ministry of Health Somaliland, Hargeisa, Somalia
| | - Solomon Yared
- Department of Biology, Jigjiga University, Jigjiga, Ethiopia
| | - Tamar E Carter
- Department of Biology, Baylor University, Waco, Texas, USA
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Ismail A, Yared S, Dugassa S, Abera A, Animut A, Erko B, Gebresilassie A. Sero-prevalence of visceral leishmaniasis and its associated factors among asymptomatic individuals visiting Denan health center, southeastern Ethiopia. Trop Dis Travel Med Vaccines 2023; 9:8. [PMID: 37430336 DOI: 10.1186/s40794-023-00196-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 06/12/2023] [Indexed: 07/12/2023] Open
Abstract
BACKGROUND In the Somali region of Ethiopia, visceral leishmaniasis (VL) is a public health concern. However, VL epidemiology and sand fly vectors have not been well studied in various areas of the regional state, including Denan district. Therefore, this study was conducted to determine the sero-prevalence, associated factors, and distribution of sand fly vectors of VL in Denan district, south-eastern Ethiopia. METHODS A facility-based cross-sectional study was conducted from April to September 2021 among VL patients with classic signs and symptoms visiting Denan Health Center in south-eastern Ethiopia. Using a convenience sampling method, 187 blood samples were collected from individuals who visited Denan Health Center during the study period. Blood samples were subjected to Direct Agglutination Test for the detection of antibodies to VL. A pre-tested structured questionnaire was also used to gather information on risk factors and other characteristics of knowledge and attitude assessment. Sand flies were also collected from indoor, peri-domestic, mixed forest, and termite mounds using light and sticky traps to determine the fauna and abundance. RESULTS The overall sero-prevalence rate was 9.63% (18/187). The sero-prevalence was significantly associated with outdoor sleeping (OR = 2.82), the presence of damp floors (OR = 7.76), and sleeping outdoor near animals (OR = 3.22). Around 53.48% of the study participants had previously heard about VL. Study participants practiced different VL control methods, including bed nets (42%), insecticide spraying (32%), smoking plant parts (14%), and environmental cleaning (8%). In total, 823 sand fly specimens, comprising 12 species in two genera (Phlebotomus and Sergentomyia), were trapped and identified. The most abundant species was Sergentomyia clydei (50.18%), followed by Phlebotomus orientalis (11.42%). Also, a higher proportion of P. orientalis was found in termite mounds (65.43%), followed by mixed forest (37.8%) and peri-domestic (20.83%) habitats. CONCLUSION The study demonstrated a 9.63% sero-positivity of VL and a remarkable gap in knowledge, attitude, and practices towards VL. P. orientalis was also detected, which could be a probable vector in this area. Thus, public education should be prioritized to improve the community's awareness of VL and its public health impact. In addition, detailed epidemiological and entomological studies are recommended.
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Affiliation(s)
- Ahmed Ismail
- College of Veterinary Medicine, Jigjiga University, Jigjiga, Ethiopia
| | - Solomon Yared
- Department of Biology, Jigjiga University, Jigjiga, Ethiopia
| | - Sisay Dugassa
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
| | - Adugna Abera
- Malaria and Neglected Tropical Diseases Research Team, Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | - Abebe Animut
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
| | - Berhanu Erko
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
| | - Araya Gebresilassie
- Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
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Aklilu E, Yared S, Gebresilassie A, Legesse B, Hailu A. Phlebotomine sandflies (Diptera: Psychodidae) of Ethiopia. Heliyon 2023; 9:e14344. [PMID: 36925525 PMCID: PMC10011004 DOI: 10.1016/j.heliyon.2023.e14344] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 02/17/2023] [Accepted: 03/02/2023] [Indexed: 03/11/2023] Open
Abstract
Phlebotomine sandflies have a long history of association with humans, which makes them the only proven natural vectors of Leishmania species, the parasitic protozoans that cause leishmaniases in humans and animals. In Ethiopia, the three forms of leishmaniases, viz., visceral, dermal and mucocutaneous are endemic in different parts of the country. Since the first report of phlebotomine sandflies in Ethiopia in 1936, the distribution of different species and their role in the transmission of leishmaniases have been extensively studied. The objective of this review was to summarize the patchy information and give an updated list of phlebotomine sandfly species in Ethiopia and their known geographical distribution in the country. Peer-reviewed literature search was conducted using online databases. All articles published which focus on distribution and medical importance of Phlebotomus and Sergentomyia species of Ethiopia starting from 1936 up to 2022 were reviewed. Until July 2022, 65 phlebotomine sandfly species have been reported, belonging to the genus Phlebotomus and Sergentomyia. The genus Phlebotomus in Ethiopia is represented by six subgenera such as Adlerius, Anaphlebotomus, Larroussius, Paraphlebotomus Phlebotomus and Synphlebotomus, whereas the genus Sergentomyia is represented by six subgenera, namely Grassomyia, Parrotomyia, Parvidens, Rondanomyia, Sergentomyia, and Sintonius.
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Affiliation(s)
- Esayas Aklilu
- Vector Biology and Control Unit, Aklilu Lema Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
| | - Solomon Yared
- Department of Biology, Jigjiga University, Jigjiga, Ethiopia
| | - Araya Gebresilassie
- Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Behailu Legesse
- Department of Geography, Madda Walabu University, Bale-Robe, Ethiopia
| | - Asrat Hailu
- Department of Microbiology, Immunology and Parasitology, Faculty of Medicine, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
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Waymire E, Duddu S, Yared S, Getachew D, Dengela D, Bordenstein SR, Balkew M, Zohdy S, Irish SR, Carter TE. Wolbachia 16S rRNA haplotypes detected in wild Anopheles stephensi in eastern Ethiopia. Parasit Vectors 2022; 15:178. [PMID: 35610655 PMCID: PMC9128127 DOI: 10.1186/s13071-022-05293-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 04/22/2022] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND About two out of three Ethiopians are at risk of malaria, a disease caused by the parasites Plasmodium falciparum and Plasmodium vivax. Anopheles stephensi, an invasive vector typically found in South Asia and the Middle East, was recently found to be distributed across eastern and central Ethiopia and is capable of transmitting both P. falciparum and P. vivax. The detection of this vector in the Horn of Africa (HOA) coupled with widespread insecticide resistance requires that new methods of vector control be investigated in order to control the spread of malaria. Wolbachia, a naturally occurring endosymbiotic bacterium of mosquitoes, has been identified as a potential vector control tool that can be explored for the control of malaria transmission. Wolbachia could be used to control the mosquito population through suppression or potentially decrease malaria transmission through population replacement. However, the presence of Wolbachia in wild An. stephensi in eastern Ethiopia is unknown. This study aimed to identify the presence and diversity of Wolbachia in An. stephensi across eastern Ethiopia. METHODS DNA was extracted from An. stephensi collected from eastern Ethiopia in 2018 and screened for Wolbachia using a 16S targeted PCR assay, as well as multilocus strain typing (MLST) PCR assays. Haplotype and phylogenetic analysis of the sequenced 16S amplicons were conducted to compare with Wolbachia from countries across Africa and Asia. RESULTS Twenty out of the 184 mosquitoes screened were positive for Wolbachia, with multiple haplotypes detected. In addition, phylogenetic analysis revealed two superclades, representing Wolbachia supergroups A and B (bootstrap values of 81 and 72, respectively) with no significant grouping of geographic location or species. A subclade with a bootstrap value of 89 separates the Ethiopian haplotype 2 from other sequences in that superclade. CONCLUSIONS These findings provide the first evidence of natural Wolbachia populations in wild An. stephensi in the HOA. They also identify the need for further research to confirm the endosymbiotic relationship between Wolbachia and An. stephensi and to investigate its utility for malaria control in the HOA.
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Affiliation(s)
| | - Sowmya Duddu
- Department of Biology, Baylor University, Waco, TX USA
| | | | | | - Dereje Dengela
- PMI VectorLink Ethiopia Project, Abt Associates, Addis Ababa, Ethiopia
| | | | - Meshesha Balkew
- PMI VectorLink Ethiopia Project, Abt Associates, Addis Ababa, Ethiopia
| | - Sarah Zohdy
- U.S. President’s Malaria Initiative and Entomology Branch, Centers for Disease Control and Prevention, Atlanta, GA USA
| | - Seth R. Irish
- U.S. President’s Malaria Initiative and Entomology Branch, Centers for Disease Control and Prevention, Atlanta, GA USA
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Carter TE, Gebresilassie A, Hansel S, Damodaran L, Montgomery C, Bonnell V, Lopez K, Janies D, Yared S. Analysis of the Knockdown Resistance Locus (kdr) in Anopheles stephensi, An. arabiensis, and Culex pipiens s.l. for Insight Into the Evolution of Target-site Pyrethroid Resistance in Eastern Ethiopia. Am J Trop Med Hyg 2022; 106:632-638. [PMID: 35008054 PMCID: PMC8832926 DOI: 10.4269/ajtmh.20-1357] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 10/08/2021] [Indexed: 11/23/2022] Open
Abstract
The malaria vector, Anopheles stephensi, which is typically restricted to South Asia and the Middle East, was recently detected in the Horn of Africa. Addressing the spread of this vector could involve integrated vector control that considers the status of insecticide resistance of multiple vector species in the region. Previous reports indicate that the knockdown resistance mutations (kdr) in the voltage-gated sodium channel (vgsc) are absent in both pyrethroid-resistant and pyrethroid-sensitive An. stephensi in eastern Ethiopia; however, similar information about other vector species in the same areas is limited. In this study, kdr and the neighboring intron were analyzed in An. stephensi, An. arabiensis, and Culex pipiens s.l. collected between 2016 and 2017 to determine the evolutionary history of kdr in eastern Ethiopia. A sequence analysis revealed that all of Cx. pipiens s.l. (N = 42) and 71.6% of the An. arabiensis (N = 67) carried kdr L1014F, which is known to confer target-site pyrethroid resistance. Intronic variation was only observed in An. stephensi (six segregating sites, three haplotypes), which was previously shown to have no kdr mutations. In addition, no evidence of non-neutral evolutionary processes was detected at the An. stephensi kdr intron, thereby further supporting the target-site mechanism not being a major resistance mechanism in this An. stephensi population. Overall, these results show key differences in the evolution of target-site pyrethroid/dichlorodiphenyltrichloroethane resistance mutations in populations of vector species from the same region. Variations in insecticide resistance mechanism profiles between eastern Ethiopian mosquito vectors may lead to different responses to insecticides used in integrated vector control.
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Affiliation(s)
| | - Araya Gebresilassie
- 2Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Shantoy Hansel
- 3Department of Bioinformatics and Genomics, University of North Carolina at Charlotte, Charlotte, North Carolina
| | | | - Callum Montgomery
- 3Department of Bioinformatics and Genomics, University of North Carolina at Charlotte, Charlotte, North Carolina
| | - Victoria Bonnell
- 5Department of Molecular Biology and Biochemistry, Pennsylvania State University, State College, Pennsylvania
| | - Karen Lopez
- 3Department of Bioinformatics and Genomics, University of North Carolina at Charlotte, Charlotte, North Carolina
| | - Daniel Janies
- 3Department of Bioinformatics and Genomics, University of North Carolina at Charlotte, Charlotte, North Carolina
| | - Solomon Yared
- 6Department of Biology, Jigjiga University, Jigjiga, Ethiopia
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Carter TE, Yared S, Getachew D, Spear J, Choi SH, Samake JN, Mumba P, Dengela D, Yohannes G, Chibsa S, Murphy M, Dissanayake G, Flately C, Lopez K, Janies D, Zohdy S, Irish SR, Balkew M. Genetic diversity of Anopheles stephensi in Ethiopia provides insight into patterns of spread. Parasit Vectors 2021; 14:602. [PMID: 34895319 PMCID: PMC8665610 DOI: 10.1186/s13071-021-05097-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 11/12/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The recent detection of the South Asian malaria vector Anopheles stephensi in the Horn of Africa (HOA) raises concerns about the impact of this mosquito on malaria transmission in the region. Analysis of An. stephensi genetic diversity and population structure can provide insight into the history of the mosquito in the HOA to improve predictions of future spread. We investigated the genetic diversity of An. stephensi in eastern Ethiopia, where detection suggests a range expansion into this region, in order to understand the history of this invasive population. METHODS We sequenced the cytochrome oxidase subunit I (COI) and cytochrome B gene (CytB) in 187 An. stephensi collected from 10 sites in Ethiopia in 2018. Population genetic, phylogenetic, and minimum spanning network analyses were conducted for Ethiopian sequences. Molecular identification of blood meal sources was also performed using universal vertebrate CytB sequencing. RESULTS Six An. stephensi COI-CytB haplotypes were observed, with the highest number of haplotypes in the northeastern sites (Semera, Bati, and Gewana towns) relative to the southeastern sites (Kebridehar, Godey, and Degehabur) in eastern Ethiopia. We observed population differentiation, with the highest differentiation between the northeastern sites compared to central sites (Erer Gota, Dire Dawa, and Awash Sebat Kilo) and the southeastern sites. Phylogenetic and network analysis revealed that the HOA An. stephensi are more genetically similar to An. stephensi from southern Asia than from the Arabian Peninsula. Finally, molecular blood meal analysis revealed evidence of feeding on cows, goats, dogs, and humans, as well as evidence of multiple (mixed) blood meals. CONCLUSION We show that An. stephensi is genetically diverse in Ethiopia and with evidence of geographical structure. Variation in the level of diversity supports the hypothesis for a more recent introduction of An. stephensi into southeastern Ethiopia relative to the northeastern region. We also find evidence that supports the hypothesis that HOA An. stephensi populations originate from South Asia rather than the Arabian Peninsula. The evidence of both zoophagic and anthropophagic feeding support the need for additional investigation into the potential for livestock movement to play a role in vector spread in this region.
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Affiliation(s)
- Tamar E Carter
- Department of Biology, Baylor University, Waco, TX, USA.
| | - Solomon Yared
- Department of Biology, Jigjiga University, Jigjiga, Ethiopia
| | | | - Joseph Spear
- Department of Biology, Baylor University, Waco, TX, USA
| | - Sae Hee Choi
- Department of Biology, Baylor University, Waco, TX, USA
| | | | - Peter Mumba
- USAID, Addis Ababa, Ethiopia
- Abt Associates, PMI VectorLink Ethiopia Project, Addis Ababa, Ethiopia
| | - Dereje Dengela
- Abt Associates, PMI VectorLink Project, Rockville, MD, USA
| | - Gedeon Yohannes
- Abt Associates, PMI VectorLink Ethiopia Project, Addis Ababa, Ethiopia
| | - Sheleme Chibsa
- U.S President's Malaria Initiative (PMI) Program, Addis Ababa, Ethiopia
| | - Matthew Murphy
- USAID, Bureau for Global Health, Office of Infectious Disease, Malaria Division, 2100 Crystal Drive| 10082B, Arlington, VA, 22202, USA
| | | | - Cecilia Flately
- Abt Associates, PMI VectorLink Ethiopia Project, Addis Ababa, Ethiopia
| | - Karen Lopez
- Department of Bioinformatics and Genomics, University of North Carolina at Charlotte, Charlotte, NC, USA
| | - Daniel Janies
- Department of Bioinformatics and Genomics, University of North Carolina at Charlotte, Charlotte, NC, USA
| | - Sarah Zohdy
- U.S. President's Malaria Initiative and Entomology Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Seth R Irish
- U.S. President's Malaria Initiative and Entomology Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Meshesha Balkew
- Abt Associates, PMI VectorLink Ethiopia Project, Addis Ababa, Ethiopia
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Balkew M, Mumba P, Yohannes G, Abiy E, Getachew D, Yared S, Worku A, Gebresilassie A, Tadesse FG, Gadisa E, Esayas E, Ashine T, Ejeta D, Dugassa S, Yohannes M, Lemma W, Yewhalaw D, Chibsa S, Teka H, Murphy M, Yoshimizu M, Dengela D, Zohdy S, Irish S. Correction to: An update on the distribution, bionomics, and insecticide susceptibility of Anopheles stephensi in Ethiopia, 2018-2020. Malar J 2021; 20:331. [PMID: 34320989 PMCID: PMC8320088 DOI: 10.1186/s12936-021-03852-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- Meshesha Balkew
- Abt Associates, PMI VectorLink Ethiopia Project, Addis Ababa, Ethiopia
| | - Peter Mumba
- Abt Associates, PMI VectorLink Ethiopia Project, Addis Ababa, Ethiopia
| | - Gedeon Yohannes
- Abt Associates, PMI VectorLink Ethiopia Project, Addis Ababa, Ethiopia
| | - Ephrem Abiy
- Abt Associates, PMI VectorLink Ethiopia Project, Addis Ababa, Ethiopia
| | | | | | | | | | | | | | | | | | | | | | | | | | | | - Sheleme Chibsa
- US President's Malaria Initiative (PMI), Addis Ababa, Ethiopia.,United States Agency for International Development (USAID), Addis Ababa, Ethiopia
| | - Hiwot Teka
- Armauer Hansen Research Institute, Addis Ababa, Ethiopia.,US President's Malaria Initiative (PMI), Addis Ababa, Ethiopia.,United States Agency for International Development (USAID), Addis Ababa, Ethiopia
| | - Matt Murphy
- US President's Malaria Initiative (PMI), Addis Ababa, Ethiopia.,Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Melissa Yoshimizu
- US President's Malaria Initiative (PMI), Addis Ababa, Ethiopia.,US President's Malaria Initiative, USAID, Washington, DC, USA
| | - Dereje Dengela
- Abt Associates, PMI VectorLink Project, Rockville, MD, USA
| | - Sarah Zohdy
- US President's Malaria Initiative (PMI), Addis Ababa, Ethiopia.,Entomology Branch Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Seth Irish
- US President's Malaria Initiative (PMI), Addis Ababa, Ethiopia. .,Entomology Branch Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.
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12
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Balkew M, Mumba P, Yohannes G, Abiy E, Getachew D, Yared S, Worku A, Gebresilassie A, Tadesse FG, Gadisa E, Esayas E, Ashine T, Ejeta D, Dugassa S, Yohannes M, Lemma W, Yewhalaw D, Chibsa S, Teka H, Murphy M, Yoshimizu M, Dengela D, Zohdy S, Irish S. An update on the distribution, bionomics, and insecticide susceptibility of Anopheles stephensi in Ethiopia, 2018-2020. Malar J 2021; 20:263. [PMID: 34107943 PMCID: PMC8189708 DOI: 10.1186/s12936-021-03801-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 06/03/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Anopheles stephensi, an invasive malaria vector, was first detected in Africa nearly 10 years ago. After the initial finding in Djibouti, it has subsequently been found in Ethiopia, Sudan and Somalia. To better inform policies and vector control decisions, it is important to understand the distribution, bionomics, insecticide susceptibility, and transmission potential of An. stephensi. These aspects were studied as part of routine entomological monitoring in Ethiopia between 2018 and 2020. METHODS Adult mosquitoes were collected using human landing collections, pyrethrum spray catches, CDC light traps, animal-baited tent traps, resting boxes, and manual aspiration from animal shelters. Larvae were collected using hand-held dippers. The source of blood in blood-fed mosquitoes and the presence of sporozoites was assessed through enzyme-linked immunosorbent assays (ELISA). Insecticide susceptibility was assessed for pyrethroids, organophosphates and carbamates. RESULTS Adult An. stephensi were collected with aspiration, black resting boxes, and animal-baited traps collecting the highest numbers of mosquitoes. Although sampling efforts were geographically widespread, An. stephensi larvae were collected in urban and rural sites in eastern Ethiopia, but An. stephensi larvae were not found in western Ethiopian sites. Blood-meal analysis revealed a high proportion of blood meals that were taken from goats, and only a small proportion from humans. Plasmodium vivax was detected in wild-collected An. stephensi. High levels of insecticide resistance were detected to pyrethroids, carbamates and organophosphates. Pre-exposure to piperonyl butoxide increased susceptibility to pyrethroids. Larvae were found to be susceptible to temephos. CONCLUSIONS Understanding the bionomics, insecticide susceptibility and distribution of An. stephensi will improve the quality of a national response in Ethiopia and provide additional information on populations of this invasive species in Africa. Further work is needed to understand the role that An. stephensi will have in Plasmodium transmission and malaria case incidence. While additional data are being collected, national programmes can use the available data to formulate and operationalize national strategies against the threat of An. stephensi.
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Affiliation(s)
- Meshesha Balkew
- Abt Associates, PMI VectorLink Ethiopia Project, Addis Ababa, Ethiopia
| | - Peter Mumba
- Abt Associates, PMI VectorLink Ethiopia Project, Addis Ababa, Ethiopia
| | - Gedeon Yohannes
- Abt Associates, PMI VectorLink Ethiopia Project, Addis Ababa, Ethiopia
| | - Ephrem Abiy
- Abt Associates, PMI VectorLink Ethiopia Project, Addis Ababa, Ethiopia
| | | | | | | | | | | | | | | | | | | | | | | | | | | | - Sheleme Chibsa
- US President's Malaria Initiative (PMI), Addis Ababa, Ethiopia.,United States Agency for International Development (USAID), Addis Ababa, Ethiopia
| | - Hiwot Teka
- Armauer Hansen Research Institute, Addis Ababa, Ethiopia.,US President's Malaria Initiative (PMI), Addis Ababa, Ethiopia.,United States Agency for International Development (USAID), Addis Ababa, Ethiopia
| | - Matt Murphy
- US President's Malaria Initiative (PMI), Addis Ababa, Ethiopia.,Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Melissa Yoshimizu
- US President's Malaria Initiative (PMI), Addis Ababa, Ethiopia.,US President's Malaria Initiative, USAID, Washington, DC, USA
| | - Dereje Dengela
- Abt Associates, PMI VectorLink Project, Rockville, MD, USA
| | - Sarah Zohdy
- US President's Malaria Initiative (PMI), Addis Ababa, Ethiopia.,Entomology Branch Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Seth Irish
- US President's Malaria Initiative (PMI), Addis Ababa, Ethiopia. .,Entomology Branch Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.
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Aklilu E, Kindu M, Gebresilassie A, Yared S, Tekie H, Balkew M. Environmental Factors Associated with Larval Habitats of Anopheline Mosquitoes (Diptera: Culicidae) in Metema District, Northwestern Ethiopia. J Arthropod Borne Dis 2020; 14:153-161. [PMID: 33365343 PMCID: PMC7738925 DOI: 10.18502/jad.v14i2.3733] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 05/26/2020] [Indexed: 11/24/2022] Open
Abstract
Background: Malaria is one of the major public health concerns in Ethiopia. Control options available for the management of malaria, include case detection, personal protection and larval source management. Effective control of Anopheles larvae largely depends on understanding of the habitats of the vectors. The aims of this study were to identify the breeding habitats of mosquitoes and characterize the larval habitats in Gende Wuha Town in northwestern Ethiopia. Methods: Different aquatic habitats were sampled and characterized for anopheline larvae from November 2012 to June 2013. Results: In total, 2784 larvae of Anopheles mosquitoes were collected from various breeding habitats. Microscopic identification of the III and IV instars revealed the presence of seven Anopheles species. Of the Anopheles spp, Anopheles gambiae s.l. (80%) was the most predominant species in the study area. Spearman correlation coefficient results also determined that the density of An. gambiae s.l. increased significantly with habitat temperature (r= 0.346, p< 0.01). Significantly higher An. gambiae s.l. larvae were obtained in non-shaded habitats (z= −3.120, p< 0.05) when compared with shaded habitats. Conclusion: The current study demonstrated An. gambiae s.l., the principal malaria vector in the country, is the predominant species in the larval sampling habitats. It was also noted the importance of edge of stream as larva breeding habitats for this species during the dry season of the year. Therefore, attention should be given for this breeding habitat for control of the vector during dry season.
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Affiliation(s)
- Esayas Aklilu
- Department of Biology, Mada Walabu University, Bale-Robe, Ethiopia
| | - Mizan Kindu
- Department of Parasitology, School of Medicine, Microbiology and Immunology, MadaWalabu University, Bale-Robe, Ethiopia
| | - Araya Gebresilassie
- Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Solomon Yared
- Department of Biology, Jigjiga University, Jigjiga, Ethiopia
| | - Habte Tekie
- Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Meshesha Balkew
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
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14
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Esayas E, Tufa A, Massebo F, Ahemed A, Ibrahim I, Dillu D, Bogale EA, Yared S, Deribe K. Malaria epidemiology and stratification of incidence in the malaria elimination setting in Harari Region, Eastern Ethiopia. Infect Dis Poverty 2020; 9:160. [PMID: 33222698 PMCID: PMC7682082 DOI: 10.1186/s40249-020-00773-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 11/02/2020] [Indexed: 12/13/2022] Open
Abstract
Background Ethiopia has shown notable progress in reducing the burden of malaria over the past two decades. Because of this progress, the country has shifted efforts from control to elimination of malaria. This study was conducted to analyse the malaria epidemiology and stratification of incidence in the malaria elimination setting in eastern Ethiopia. Methods A retrospective study was conducted to analyse the epidemiology of malaria by reviewing the district health office data from 2013 to 2019 in Harari Region. In addition, three years of sub-district level malaria data were used to stratify the malaria transmission intensity. Malaria interventions (Long-lasting insecticidal nets [LLIN] and indoor residual spraying [IRS]) employed were reviewed to analyse the intervention coverage at the Regional level. Descriptive statistics were used to show the malaria transmission in terms of years, season and species of the malaria parasite. Incidence rate per 1000 population and death rate per 1 000 000 population at risk were computed using the total population of each year. Results In the Harari Region, malaria incidence showed a more pronounced declining trend from 2017 to 2019. Plasmodium falciparum, P. vivax and mixed infections accounted for 69.2%, 30.6% and 0.2% of the cases, respectively. There was an increment in malaria intervention coverage and improved malaria diagnosis. In the year 2019 the coverage of LLIN and IRS in the Region were 93.4% and 85.1% respectively. The annual malaria incidence rate dropped from 42.9 cases per 1000 population in 2013 to 6.7 cases per 1000 population in 2019. Malaria-related deaths decreased from 4.7 deaths per 1 000 000 people annually in 2013 to zero, and there have been no deaths reported since 2015. The malaria risk appears to be heterogeneous and varies between districts. A higher number of malaria cases were recorded in Erer and Jenella districts, which constitute 62% of the cases in the Region. According to the sub-district level malaria stratification, there was shrinkage in the malaria transmission map and about 70% of the sub-districts have achieved elimination targets. Conclusions In the Harari Region, malaria morbidity and mortality have been significantly declined. Thus, if this achievement is sustained and scaling-up of the existing malaria prevention and control strategies by focusing on those populations living in the higher malaria transmission districts and sub-districts, planning of malaria elimination from the study area might be feasible.
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Affiliation(s)
- Endashaw Esayas
- Harari Regional Health Bureau, Malaria Control and Elimination Program, Harar, Ethiopia. .,Malaria and Neglected Tropical Diseases Research Directorate, Armauer Hansen Research Institute, Addis Ababa, Ethiopia.
| | - Asefa Tufa
- Harari Regional Health Bureau, Malaria Control and Elimination Program, Harar, Ethiopia
| | - Fekadu Massebo
- Department of Biology, Arba Minch University, Arba Minch, Ethiopia
| | - Abdulhamid Ahemed
- Harari Regional Health Bureau, Malaria Control and Elimination Program, Harar, Ethiopia
| | - Ibssa Ibrahim
- Harari Regional Health Bureau, Malaria Control and Elimination Program, Harar, Ethiopia
| | - Dereje Dillu
- Federal Ministry of Health, Addis Ababa, Ethiopia
| | - Eyuel Asemahegn Bogale
- Malaria and Neglected Tropical Diseases Research Directorate, Armauer Hansen Research Institute, Addis Ababa, Ethiopia
| | | | - Kebede Deribe
- Global Health and Infection Department, Brighton and Sussex Medical School, Brighton, 19PX, BN, UK.,School of Public Health, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
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Yared S, Gebressielasie A, Damodaran L, Bonnell V, Lopez K, Janies D, Carter TE. Insecticide resistance in Anopheles stephensi in Somali Region, eastern Ethiopia. Malar J 2020; 19:180. [PMID: 32398055 PMCID: PMC7216317 DOI: 10.1186/s12936-020-03252-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 05/04/2020] [Indexed: 11/18/2022] Open
Abstract
Background The movement of malaria vectors into new areas is a growing concern in the efforts to control malaria. The recent report of Anopheles stephensi in eastern Ethiopia has raised the necessity to understand the insecticide resistance status of the vector in the region to better inform vector-based interventions. The aim of this study was to evaluate insecticide resistance in An. stephensi in eastern Ethiopia using two approaches: (1) World Health Organization (WHO) bioassay tests in An. stephensi; and (2) genetic analysis of insecticide resistance genes in An. stephensi in eastern Ethiopia. Methods Mosquito larvae and pupae were collected from Kebri Dehar. Insecticide susceptibility of An. stephensi was tested with malathion 5%, bendiocarb 0.1%, propoxur 0.1%, deltamethrin 0.05%, permethrin 0.75%, pirimiphos-methyl 0.25% and DDT 4%, according to WHO standard protocols. In this study, the knockdown resistance locus (kdr) in the voltage gated sodium channel (vgsc) and ace1R locus in the acetylcholinesterase gene (ace-1) were analysed in An. stephensi. Results All An. stephensi samples were resistant to carbamates, with mortality rates of 23% and 21% for bendiocarb and propoxur, respectively. Adult An. stephensi was also resistant to pyrethroid insecticides with mortality rates 67% for deltamethrin and 53% for permethrin. Resistance to DDT and malathion was detected in An. stephensi with mortality rates of 32% as well as An. stephensi was resistance to pirimiphos-methyl with mortality rates 14%. Analysis of the insecticide resistance loci revealed the absence of kdr L1014F and L1014S mutations and the ace1R G119S mutation. Conclusion Overall, these findings support that An. stephensi is resistant to several classes of insecticides, most notably pyrethroids. However, the absence of the kdr L1014 gene may suggest non-target site resistance mechanisms. Continuous insecticide resistance monitoring should be carried out in the region to confirm the documented resistance and exploring mechanisms conferring resistance in An. stephensi in Ethiopia.
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Affiliation(s)
- Solomon Yared
- Department of Biology, Jigjiga University, Jigjiga, Ethiopia.
| | - Araya Gebressielasie
- Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | | | - Victoria Bonnell
- Department of Molecular Biology and Biochemistry, Pennsylvania State University, State College, PA, USA
| | - Karen Lopez
- Department of Bioinformatics and Genomics, University of North Carolina at Charlotte, Charlotte, NC, USA
| | - Daniel Janies
- Department of Bioinformatics and Genomics, University of North Carolina at Charlotte, Charlotte, NC, USA
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16
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Balkew M, Mumba P, Dengela D, Yohannes G, Getachew D, Yared S, Chibsa S, Murphy M, George K, Lopez K, Janies D, Choi SH, Spear J, Irish SR, Carter TE. Geographical distribution of Anopheles stephensi in eastern Ethiopia. Parasit Vectors 2020; 13:35. [PMID: 31959237 PMCID: PMC6971998 DOI: 10.1186/s13071-020-3904-y] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 01/09/2020] [Indexed: 01/29/2023] Open
Abstract
Background The recent detection of the South Asian malaria vector Anopheles stephensi in Ethiopia and other regions in the Horn of Africa has raised concerns about its potential impact on malaria transmission. We report here the findings of a survey for this species in eastern Ethiopia using both morphological and molecular methods for species identification. Methods Adult and larval/pupal collections were conducted at ten sites in eastern Ethiopia and Anopheles specimens were identified using standard morphological keys and genetic analysis. Results In total, 2231 morphologically identified An. stephensi were collected. A molecular approach incorporating both PCR endpoint assay and sequencing of portions of the internal transcribed spacer 2 (ITS2) and cytochrome c oxidase subunit 1 (cox1) loci confirmed the identity of the An. stephensi in most cases (119/124 of the morphologically identified An. stephensi confirmed molecularly). Additionally, we observed Aedes aegypti larvae and pupae at many of the An. stephensi larval habitats. Conclusions Our findings show that An. stephensi is widely distributed in eastern Ethiopia and highlight the need for further surveillance in the southern, western and northern parts of the country and throughout the Horn of Africa.
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Affiliation(s)
- Meshesha Balkew
- Abt Associates, PMI VectorLink Ethiopia Project, Addis Ababa, Ethiopia.
| | - Peter Mumba
- Abt Associates, PMI VectorLink Ethiopia Project, Addis Ababa, Ethiopia
| | - Dereje Dengela
- Abt Associates, PMI VectorLink Project, Rockville, MD, USA
| | - Gedeon Yohannes
- Abt Associates, PMI VectorLink Ethiopia Project, Addis Ababa, Ethiopia
| | | | | | - Sheleme Chibsa
- US President's Malaria Initiative (PMI), Addis Ababa, Ethiopia.,United States Agency for International Development (USAID), Addis Ababa, Ethiopia
| | - Matthew Murphy
- US President's Malaria Initiative (PMI), Addis Ababa, Ethiopia.,Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Kristen George
- US President's Malaria Initiative (PMI), Addis Ababa, Ethiopia.,Bureau for Global Health, Office of Infectious Disease, Malaria Division, USAID, Arlington, VA, USA
| | - Karen Lopez
- University of North Carolina at Charlotte, Charlotte, NC, USA
| | - Daniel Janies
- University of North Carolina at Charlotte, Charlotte, NC, USA
| | | | | | - Seth R Irish
- US President's Malaria Initiative (PMI), Addis Ababa, Ethiopia.,Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, USA
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17
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Gebresilassie A, Yared S, Aklilu E. Sandfly fauna and ecological analysis of Phlebotomus orientalis and Phlebotomus martini in the lowland foci of visceral leishmaniasis in Somali Regional State, southeast Ethiopia. ASIAN PAC J TROP MED 2020. [DOI: 10.4103/1995-7645.273572] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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18
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Yared S, Gebresilassie A, Abbasi I, Aklilu E, Kirstein OD, Balkew M, Brown AS, Clouse RM, Warburg A, Hailu A, Gebre-Michael T. A molecular analysis of sand fly blood meals in a visceral leishmaniasis endemic region of northwestern Ethiopia reveals a complex host-vector system. Heliyon 2019; 5:e02132. [PMID: 31384683 PMCID: PMC6661399 DOI: 10.1016/j.heliyon.2019.e02132] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 05/01/2019] [Accepted: 07/18/2019] [Indexed: 11/04/2022] Open
Abstract
Background Visceral leishmaniasis (VL, or “kala-azar”) is a major cause of disability and death, especially in East Africa. Its vectors, sand flies (Diptera: Psychodidae: Phlebotominae), are poorly controlled and guarded against in these regions, owing in part to a lack of understanding about their feeding behavior. Methods A total of 746 freshly fed female sand flies were collected in five population centers in Kafta Humera (northwestern Ethiopia), where VL is endemic. Flies were collected from habitats that ranged from inside houses to open fields, using light traps and sticky traps. Sources of sand fly blood meals were identified using enzyme-linked immunosorbent assays (ELISA) and DNA amplification with reverse-line blot analysis (PCR-RLB); 632 specimens were screened using ELISA, 408 of which had identifiable blood meals, and 114 were screened using PCR-RLB, 53 of which yielded identifications. Fly species determinations were based on morphology, and those specimens subjected to PCR-RLB were also screened for Leishmania parasites using conventional PCR to amplify the nuclear marker ITS1 (internal transcribed spacer 1) with Leishmania-specific primers. Results More than three-fourths of all sand flies collected were Phlebotomus orientalis, and the remaining portion was comprised of nine other species. Nearly two-thirds of P. orientalis specimens were collected at village peripheries. The most common blood source for all flies was donkey (33.9% of all identifications), followed by cow (24.2%), human (17.6%), dog (11.8%), and goat or sheep (8.6%); mixtures of blood meals from different sources were found in 28.2% of all flies screened. Unidentified blood meals, presumably from wildlife, not domestic animals, were significantly higher in farm fields. Leishmania parasites were not detected in any of the 114 flies screened, not surprising given an expected infection rate of 1–5 out of 1,000. Meals that included a mixture of human and cow blood were significantly more frequent relative to all cow meals than human blood meals were to non-cow meals, suggesting a zoopotentiative interaction between cows and humans in this system. Conclusions Habitat and host preferences of sand fly vectors in Kafta Humera confirmed the finding of previous reports that the main vector in the region, Phlebotomus orientalis, is a highly opportunistic feeder that prefers large animals and is most commonly found at village peripheries. These results were similar to those of a previous study conducted in a nearby region (Tahtay Adiabo), except for the role of cattle on the prevalence of human blood meals. Preliminary examinations of blood meal data from different settings point to the need for additional surveys and field experiments to understand the role of livestock on biting risks.
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Affiliation(s)
- Solomon Yared
- Department of Biology, Jigjiga University, Jigjiga, Ethiopia
| | - Araya Gebresilassie
- Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Ibrahim Abbasi
- The Kuvin Center for the Study of Infectious and Tropical Diseases, Institute for Medical Research, The Hebrew University, Israel
| | - Essayas Aklilu
- Department of Biology, Mada Walabu University, Bale-Robe, Ethiopia
| | - Oscar D Kirstein
- The Kuvin Center for the Study of Infectious and Tropical Diseases, Institute for Medical Research, The Hebrew University, Israel
| | - Meshesha Balkew
- President's Malaria Initiative (PMI) Vector Link Project, Ethiopia
| | - Adam S Brown
- Harvard University, Department of Biomedical Informatics, Boston, MA, United States
| | - Ronald M Clouse
- American Museum of Natural History, New York, NY, United States
| | - Alon Warburg
- The Kuvin Center for the Study of Infectious and Tropical Diseases, Institute for Medical Research, The Hebrew University, Israel
| | - Asrat Hailu
- Department of Microbiology, Immunology & Parasitology, School of Medicine; Addis Ababa University, Addis Ababa, Ethiopia
| | - Teshome Gebre-Michael
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
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Carter TE, Yared S, Hansel S, Lopez K, Janies D. Sequence-based identification of Anopheles species in eastern Ethiopia. Malar J 2019; 18:135. [PMID: 30992003 PMCID: PMC6469081 DOI: 10.1186/s12936-019-2768-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 04/04/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The recent finding of a typically non-African Anopheles species in eastern Ethiopia emphasizes the need for detailed species identification and characterization for effective malaria vector surveillance. Molecular approaches increase the accuracy and interoperability of vector surveillance data. To develop effective molecular assays for Anopheles identification, it is important to evaluate different genetic loci for the ability to characterize species and population level variation. Here the utility of the internal transcribed spacer 2 (ITS2) and cytochrome oxidase I (COI) loci for detection of Anopheles species from understudied regions of eastern Ethiopia was investigated. METHODS Adult mosquitoes were collected from the Harewe locality (east) and Meki (east central) Ethiopia. PCR and Sanger sequencing were performed for portions of the ITS2 and COI loci. Both NCBI's Basic Local Alignment Search tool (BLAST) and phylogenetic analysis using a maximum-likelihood approach were performed to identify species of Anopheles specimens. RESULTS Two species from the east Ethiopian collection, Anopheles arabiensis and Anopheles pretoriensis were identified. Analyses of ITS2 locus resulted in delineation of both species. In contrast, analysis of COI locus could not be used to delineate An. arabiensis from other taxa in Anopheles gambiae complex, but could distinguish An. pretoriensis sequences from sister taxa. CONCLUSION The lack of clarity from COI sequence analysis highlights potential challenges of species identification within species complexes. These results provide supporting data for the development of molecular assays for delineation of Anopheles in east Ethiopia.
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Affiliation(s)
- Tamar E Carter
- Department of Biology, Baylor University, Waco, TX, USA.
| | - Solomon Yared
- Department of Biology, Jigjiga University, Jigjiga, Ethiopia
| | - Shantoy Hansel
- Department of Bioinformatics and Genomics, University of North Carolina at Charlotte, Charlotte, NC, USA
| | - Karen Lopez
- Department of Bioinformatics and Genomics, University of North Carolina at Charlotte, Charlotte, NC, USA
| | - Daniel Janies
- Department of Bioinformatics and Genomics, University of North Carolina at Charlotte, Charlotte, NC, USA
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Yared S, Gebresilassie A, Akililu E, Deribe K, Balkew M, Warburg A, Hailu A, Gebre-Michael T. Diversity and altitudinal distribution of phlebotomine sand flies (Diptera: Psychodidae) in visceral leishmaniasis endemic areas of northwest Ethiopia. Acta Trop 2017; 176:1-10. [PMID: 28712974 PMCID: PMC5590723 DOI: 10.1016/j.actatropica.2017.07.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 06/29/2017] [Accepted: 07/09/2017] [Indexed: 10/24/2022]
Abstract
BACKGROUND The Leishmaniases are caused by the protozoan parasites of the genus Leishmania and are transmitted to humans by the bite of infected female phlebotomine sand flies. Both visceral and cutaneous leishmaniases are widely distributed in different parts of Ethiopia. The aim of this study was to determine the diversity and altitudinal distribution of phlebotomine sand flies from Kafta Humera to Gondar town in northwest Ethiopia. METHODS Seven localities were selected with distinct altitudinal variations between 550m above sea level (m a.s.l) and 2300m a.s.l. In each locality, sand flies were collected using standard CDC light traps and sticky traps during the active sand fly season from December 2012 to May 2013. Shannon-Weiner species diversity index and Jaccard's coefficient were used to estimate species diversity and similarity between altitudes and localities, respectively. RESULTS A total of 89,044 sand flies (41,798 males and 47, 246 females) were collected from the seven localities/towns throughout the study period. Twenty-two species belonging to 11 species in the genus Phlebotomus and 11 species in the genus Sergentomyia were documented. Of these, Sergentomyia clydei (25.87%), S. schwetzi (25.21%), S. africana (24.65%), S. bedfordi (8.89%), Phlebotomus orientalis (6.43%), and S. antennata (4.8%) were the most prevalent species. The remaining 10 Phlebotomus species and six Sergentomyia were less frequent catches. In CDC light trap and sticky trap, higher species diversity and richness for both male and female sand flies was observed at low altitude ranging from 550 to 699m a.s.l in Adebay village in Kafta Humera district whereas low species richness and high evenness of both sexes were also observed in an altitude 1950-2300m a.s.l. CONCLUSION The results revealed that the presence of leishmaniasis vectors such as P. orientalis, P. longipes, P. papatasi, and P. duboscqi in different altitudes in northwest Ethiopia. P. orientalis a vector of L. donovani, occurred between altitude 500-1100m a.s.l, the area could be at high risk of VL. P. longipes a vector of L. aethiopica, was recorded in the highland area in Tikil-Dingay and Gondar town, implicating the possibility of CL transmission. Hence, further investigation into vector competence in relation to leishmaniasis (VL and CL) in the region is very vital.
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Aklilu E, Gebresilassie A, Yared S, Kindu M, Tekie H, Balkew M, Warburg A, Hailu A, Gebre-Michael T. Comparative study on the nocturnal activity of phlebotomine sand flies in a highland and lowland foci of visceral leishmaniasis in north-western Ethiopia with special reference to Phlebotomus orientalis. Parasit Vectors 2017; 10:393. [PMID: 28830569 PMCID: PMC5568301 DOI: 10.1186/s13071-017-2339-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 08/17/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Leishmania donovani, the causative agent of visceral leishmaniasis (VL), is most probably vectored by Phlebotomus orientalis in north-western Ethiopia. The aim of this study was to determine and compare the nocturnal activity patterns of Ph. orientalis in VL endemic foci of Libo-Kemkem (highland) and Metema (lowland) districts of north-western Ethiopia. METHODS Sampling of sand flies was conducted bimonthly from January-May 2012 in the highland and from March-June 2013 in the lowland. Sand flies were sampled using two CDC light traps placed in compounds occupied by both cattle and humans. Sampling of sand flies started at 18:00 h and ended at 06:00 h. Every hour, a cage was replaced by another cage. RESULTS In total, 9479 nocturnally active sand flies were collected from both study areas. Six Phlebotomus species (Ph. orientalis, Ph. duboscqi, Ph. papatasi, Ph. bergeroti, Ph. rodhaini and Ph. martini) and several Sergentomyia spp. were identified. In both areas, of the six Phlebotomus spp., Ph. orientalis was the preponderate. In the highland, the hourly activity pattern of Ph. orientalis females was higher before midnight with a peak in density between 22:00-23:00 h, whereas in the lowland after midnight between 03:00-04:00 h. CONCLUSIONS The present study showed that Ph. orientalis females exhibited different nocturnal activity patterns with a peak in the early part of the night in the highland and in the latter part of the night in the lowland areas. As the risk of acquiring L. donovani infections vary in the two areas, appropriate control strategies should be developed according to the activity of Ph. orientalis in the respective areas.
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Affiliation(s)
- Esayas Aklilu
- Department of Biology, Mada Walabu University, Bale-Robe, Ethiopia.
| | | | - Solomon Yared
- Department of Biology, Jigjiga University, Jigjiga, Ethiopia
| | - Mizan Kindu
- Department of Microbiology and Parasitology, Mada Walabu University, Bale-Robe, Ethiopia
| | - Habte Tekie
- Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Meshesha Balkew
- Aklilu Lemma Institutes of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
| | - Alon Warburg
- Faculty of Medicine, The Hebrew University, Hadassah Medical School, Jerusalem, Israel
| | - Asrat Hailu
- Department of Microbiology, Immunology and Parasitology, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Teshome Gebre-Michael
- Aklilu Lemma Institutes of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
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Aklilu E, Gebresilassie A, Yared S, Kindu M, Tekie H, Balkew M, Warburg A, Hailu A, Gebre-Michael T. Studies on sand fly fauna and ecological analysis of Phlebotomus orientalis in the highland and lowland foci of kala-azar in northwestern Ethiopia. PLoS One 2017; 12:e0175308. [PMID: 28384307 PMCID: PMC5383282 DOI: 10.1371/journal.pone.0175308] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 03/23/2017] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Visceral leishmaniasis (VL) also known as kala-azar is a growing health problem in Ethiopia with an estimated annual VL incidence between 3700 and 7400. The disease is mainly endemic in northwestern parts of the country. The aim of the current study was to determine the sand fly fauna and ecology of Phlebotomus orientalis in two endemic and ecologically distinct areas of northwestern Ethiopia. METHODS Sand flies were collected using CDC light traps, sticky traps and pyrethrum spray catches from peri-domestic, mixed forest, farm field and indoor habitats from both Libo-Kemkem (May 2011-April 2012) and Metema (October 2012-September 2013) districts. RESULTS A total of 51,411 sand fly specimens were collected and identified (10,776 from highland and 40, 635 from the lowland areas). Seven species were found in the highland area: two Phlebotomus spp. (P. orientalis and P. rodhaini) and five Sergentomyia species. Whereas 19 species were found in the lowland area: six Phlebotomus (P. orientalis, P. rodhaini, P. bergeroti, P. duboscqi, P. papatasi and P. martini) and 13 Sergentomyia species. Of the Phlebotomus spp., P. orientalis was the predominant species in both the highland (99.9%) and lowland (93.7%) areas. Indoor collections using pyrethrum spray catches and sticky traps indicated that P. orientalis has a strong exophilic and exophagic behaviors in both districts. In both areas, this species showed seasonal occurrence and showing abundance during the dry months (March-May/June) of the year and increasing in numbers till the rain season, when numbers dropped dramatically. Mean density of P. orientalis in the two areas had positive and significant correlation with mean temperature in light trap collections (P<0.05). However, mean density of P. orientalis in the two areas in sticky trap collections had positive and insignificant association with the temperature (P>0.05). Regarding the rainfall pattern, density of P. orientalis had negative and statistically insignificant correlation (for light trap collections for both areas) and significant correlation (for sticky trap collections for lowland area). CONCLUSIONS The current study indicated the variation in sand fly fauna between the highland and lowland districts, wherein, P. orientalis was found to be the most abundant Phlebotomus species. The study also determined that P. orientalis exhibits distinct seasonality, where its abundance increases during the dry season and disappears when the rainy period starts in both study areas. This entomological observation on the bionomics of P. orientalis provides significant evidence for considering vector control or preventive measures in the areas studied.
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Affiliation(s)
- Esayas Aklilu
- Department of Biology, Mada Walabu University, Bale-Robe, Ethiopia
- * E-mail:
| | | | - Solomon Yared
- Department of Biology, Jigjiga University, Jigjiga, Ethiopia
| | - Mizan Kindu
- Department of Biology, Mada Walabu University, Bale-Robe, Ethiopia
| | - Habte Tekie
- Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Meshesha Balkew
- Aklilu Lemma Institutes of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
| | - Alon Warburg
- Department of Microbiology and Molecular Genetics, The Institute of Medical Research Israel-Canada The Kuvin Center for the Study of Infectious and Tropical Diseases, Faculty of Medicine, The Hebrew University, Hadassah Medical School, Jerusalem, Israel
| | - Asrat Hailu
- Department of Microbiology, Immunology and Parasitology, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Teshome Gebre-Michael
- Aklilu Lemma Institutes of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
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Yared S, Gebresilassie A, Akililu E, Balkew M, Warburg A, Hailu A, Gebre-Michael T. Habitat preference and seasonal dynamics of Phlebotomus orientalis in urban and semi-urban areas of kala-azar endemic district of Kafta Humera, northwest Ethiopia. Acta Trop 2017; 166:25-34. [PMID: 27771421 DOI: 10.1016/j.actatropica.2016.10.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 10/06/2016] [Accepted: 10/18/2016] [Indexed: 10/20/2022]
Abstract
Visceral leishmaniasis is a significant public health problem in northwest Ethiopia, particularly in Kafta Humera district. The study was designed to determine the species composition and population dynamics of sand flies in five villages representing urban and semi-urban areas of Kafta Humera district namely, Setit Humera, Mykadra, Rawyan, Bereket and Adebay. Sand flies were collected for two to three nights monthly from May 2011 to April 2012 using CDC light-traps and sticky traps. Traps were placed in villages, at periphery of villages and farm fields. Sticky traps were also used for sampling indoor active sand flies. In total, 13,097 sand fly specimens of eight Phlebotomus species and 91,949 Sergentomyia specimens were collected. Among the Phlebotomus, P. orientalis was the predominant species (58.1%) followed by P. papatasi (29.6%), P. lesleyae (5.6%), P. bergeroti (3.8%), P. duboscqi (2.1%), P. alexandri (0.4%), P. heischi (0.2%) and P. rodhaini (0.2%). Significantly, higher number of P. orientalis was caught in Adebay village and the least in Setit Humera town. Seasonal abundance of P. orientalis increased during the dry season (January-May) and dropped drastically in the wet season (late June-September). Significant positive correlation was found between monthly abundance of P. orientalis and the monthly average air and surface soil temperature, while a negative correlation was found with monthly average rainfall and relative humidity. Higher number of P. orientalis was collected outdoors, especially in the farm fields followed by periphery of villages. Thus, various observations strongly suggested P. orientalis to be the principal vector in the study areas, where farm lands and periphery of villages were identified as the most risky habitats, whereas the indoors were the least ones. Appropriate control methods should be designed and implemented according to the knowledge of P. orientalis habitat preferences and seasonal dynamics in the district.
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Gebresilassie A, Abbasi I, Aklilu E, Yared S, Kirstein OD, Moncaz A, Tekie H, Balkew M, Warburg A, Hailu A, Gebre-Michael T. Host-feeding preference of Phlebotomus orientalis (Diptera: Psychodidae) in an endemic focus of visceral leishmaniasis in northern Ethiopia. Parasit Vectors 2015; 8:270. [PMID: 25963759 PMCID: PMC4432826 DOI: 10.1186/s13071-015-0883-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 05/04/2015] [Indexed: 11/16/2022] Open
Abstract
Background Blood-feeding behavior studies are important for estimating the efficiency of pathogen transmission and assessing the relative human disease risk. However, in Ethiopia and other parts of East Africa there are large remaining gaps in identifying the feeding habits of Phlebotomus orientalis, the vector of Leishmania donovani. The aim of the study was to determine the blood feeding patterns of P. orientalis in Tahtay Adiyabo district, northern Ethiopia. Methods For bloodmeal analysis, sandflies were collected from three different villages of Tahtay Adiyabo district using CDC light traps, sticky traps, and pyrethrum spray catches. Bloodmeal of engorged female sandflies was identified using cytochrome (cyt) b-PCR and reverse-line blotting (RLB) and enzyme linked immunosorbent assay (ELISA) assays. Results Most (637/641) of the females analyzed were P. orientalis. Successful identification of the host from bloodmeals was achieved in 83.03 and 92.1 % using cyt b PCR-RLB and ELISA, respectively. Bloodmeal analysis of P. orientalis females revealed that they have a range of hosts with predominant preference to bovines followed by donkey, human, goat, sheep, dog, and camel. Conclusion Results obtained from bloodmeal analyses demonstrate that the feeding preference of P. orientalis is mainly zoophilic, which could vary depending on the availability of hosts.
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Affiliation(s)
- Araya Gebresilassie
- Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia. .,Department of Biology, College of Natural Science, Jigjiga University, Jigjiga, Ethiopia.
| | - Ibrahim Abbasi
- Department of Microbiology and Molecular Genetics, The Institute of Medical Research Israel-Canada The Kuvin Center for the Study of Infectious and Tropical Diseases, Faculty of Medicine, The Hebrew University, Hadassah Medical School, Jerusalem, Israel.
| | - Essayas Aklilu
- Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Solomon Yared
- Department of Biology, College of Natural Science, Jigjiga University, Jigjiga, Ethiopia.
| | - Oscar David Kirstein
- Department of Microbiology and Molecular Genetics, The Institute of Medical Research Israel-Canada The Kuvin Center for the Study of Infectious and Tropical Diseases, Faculty of Medicine, The Hebrew University, Hadassah Medical School, Jerusalem, Israel.
| | - Aviad Moncaz
- Department of Microbiology and Molecular Genetics, The Institute of Medical Research Israel-Canada The Kuvin Center for the Study of Infectious and Tropical Diseases, Faculty of Medicine, The Hebrew University, Hadassah Medical School, Jerusalem, Israel.
| | - Habte Tekie
- Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Meshesha Balkew
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Alon Warburg
- Department of Microbiology and Molecular Genetics, The Institute of Medical Research Israel-Canada The Kuvin Center for the Study of Infectious and Tropical Diseases, Faculty of Medicine, The Hebrew University, Hadassah Medical School, Jerusalem, Israel.
| | - Asrat Hailu
- Department of Microbiology, Immunology and Parasitology, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Teshome Gebre-Michael
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.
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Gebresilassie A, Kirstein OD, Yared S, Aklilu E, Moncaz A, Tekie H, Balkew M, Warburg A, Hailu A, Gebre-Michael T. Species composition of phlebotomine sand flies and bionomics of Phlebotomus orientalis (Diptera: Psychodidae) in an endemic focus of visceral leishmaniasis in Tahtay Adiyabo district, Northern Ethiopia. Parasit Vectors 2015; 8:248. [PMID: 25907252 PMCID: PMC4438477 DOI: 10.1186/s13071-015-0849-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 04/09/2015] [Indexed: 11/10/2022] Open
Abstract
Background Visceral leishmaniasis (VL) is a neglected tropical disease, which is strongly associated with poverty. VL caused by Leishmania donovani and transmitted by Phlebotomus orientalis is endemic in various remote areas of north and north-west Ethiopia. The present study was designed to determine the sand fly fauna and bionomics of P. orientalis in the VL endemic focus of Tahtay Adiyabo district. Methods Sand flies were collected using CDC light traps (n = 602), sticky traps (n = 9,350) and indoor pyrethrum spray catches (n = 578 house visits) from indoor, peri-domestic and agricultural field habitats between May 2011 to April 2012. All sand fly specimens collected were identified to species level and counted. Results In total, 100,772 sand fly specimens, belonging to 25 sand fly species (nine Phlebotomus and sixteen Sergentomyia) were collected and identified. S. africana and P. orientalis made up 59.1% and 23.5% of the collected sand flies, respectively. As it could be determined from the proportion of collections from outdoor (peri-domestic and agricultural fields) and indoor locations, P. orientalis appears to exhibit increased exophilic behavior. The outdoor to indoor index was 79:1 on m2 of sticky traps. Mean density of P. orientalis caught was significantly higher on horizontally placed sticky traps (mean = 60 ± 14.56/m2/night) than vertically deployed sticky traps (12 ± 3.57/m2/night). The highest abundance of P. orientalis occurred between March and April. Through July to September, there was a sharp decline in abundance of P. orientalis population. Regarding climatic variables, P. orientalis density in light traps and on sticky traps showed a significant positive and negative association with temperature and relative humidity, respectively. However, non-significant negative correlation was observed with rainfall pattern. Conclusions Overall, P. orientalis was found to be the most abundant Phlebotomus species, showing marked seasonal abundance that mainly peaks during the dry season (March to April). Likewise, the people in the area usually sleep in compounds during these months that potentially expose them to a high risk of peri-domestic VL transmission.
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Affiliation(s)
- Araya Gebresilassie
- Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia. .,Department of Biology, College of Natural Science, Jigjiga University, Jigjiga, Ethiopia.
| | - Oscar David Kirstein
- Department of Microbiology and Molecular Genetics, The Institute of Medical Research Israel-Canada The Kuvin Center for the Study of Infectious and Tropical Diseases, Faculty of Medicine, The Hebrew University, Hadassah Medical School, Jerusalem, Israel.
| | - Solomon Yared
- Department of Biology, College of Natural Science, Jigjiga University, Jigjiga, Ethiopia. .,Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Essayas Aklilu
- Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Aviad Moncaz
- Department of Microbiology and Molecular Genetics, The Institute of Medical Research Israel-Canada The Kuvin Center for the Study of Infectious and Tropical Diseases, Faculty of Medicine, The Hebrew University, Hadassah Medical School, Jerusalem, Israel.
| | - Habte Tekie
- Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Meshesha Balkew
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Alon Warburg
- Department of Microbiology and Molecular Genetics, The Institute of Medical Research Israel-Canada The Kuvin Center for the Study of Infectious and Tropical Diseases, Faculty of Medicine, The Hebrew University, Hadassah Medical School, Jerusalem, Israel.
| | - Asrat Hailu
- Department of Microbiology, Immunology and Parasitology, College of Health Science, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Teshome Gebre-Michael
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.
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Gebresilassie A, Yared S, Aklilu E, Kirstein OD, Moncaz A, Tekie H, Balkew M, Warburg A, Hailu A, Gebre-Michael T. Host choice of Phlebotomus orientalis (Diptera: Psychodidae) in animal baited experiments: a field study in Tahtay Adiyabo district, northern Ethiopia. Parasit Vectors 2015; 8:190. [PMID: 25885333 PMCID: PMC4389315 DOI: 10.1186/s13071-015-0807-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2014] [Accepted: 03/17/2015] [Indexed: 12/21/2022] Open
Abstract
Background Host choice and feeding success of sand fly vectors of visceral leishmaniasis (VL) are important factors in understanding the epidemiology and for developing efficient control strategies. The aim of the present study was to determine the host preference of Phlebotomus orientalis in the VL focus of Tahtay Adiyabo district, northern Ethiopia. Methods Two separate experiments were conducted testing attraction of P. orientalis to humans, domestic animals, and small wild animals. The host choice of P. orientalis and other sand fly species was assessed using tent traps baited with seven different animals (human, cow, sheep, goat, donkey, dog and chicken) and a blank control. Baited traps were rotated every night in a Latin square design for two consecutive full rounds totaling 16 trap-nights. The second set of experiments tested attraction to small wild animals including; ground squirrel (Xerus rutilus), hare (Lepus sp.), gerbil (Tatera robusta) and spiny mouse (Acomys cahirinus). Animals were caged in standard rodent traps or cylindrical wire-mesh cages. The bait animals were placed in agricultural field and the attracted sand flies were collected using unlit CDC traps for 10 trapping nights. Sand fly specimens collected from each of the experiments were identified to species level and counted. Results Significant difference (P < 0.05) was observed in the attraction and feeding rate of P. orientalis to different baits. In the first experiment, cow-baited tent traps attracted the highest mean number of P. orientalis (mean = 510 flies). The engorgement rate of P. orientalis on donkey was the highest followed by cow, and much lower on goat, sheep, dog and chicken. In the case of smaller wild animals, more numbers of P. orientalis females were attracted to squirrels followed by hares, gerbils and the spiny rat. However, the engorgement rates for P. orientalis in the smaller animals were very low (1.08%) compared with larger domestic animals (30.53%). Conclusion The tendency of female P. orientalis to engorge in large numbers on certain species of domestic as well as wild animals strongly indicated that the species is primarily zoophilic in its host preference with feeding habits that may vary depending on the availability of hosts.
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Affiliation(s)
- Araya Gebresilassie
- Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia. .,Department of Biology, College of Natural Science, Jigjiga University, Jigjiga, Ethiopia.
| | - Solomon Yared
- Department of Biology, College of Natural Science, Jigjiga University, Jigjiga, Ethiopia. .,Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Essayas Aklilu
- Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Oscar David Kirstein
- Department of Microbiology and Molecular Genetics, The Institute of Medical Research Israel-Canada The Kuvin Center for the Study of Infectious and Tropical Diseases, Faculty of Medicine, The Hebrew University, Hadassah Medical School, Jerusalem, Israel.
| | - Aviad Moncaz
- Department of Microbiology and Molecular Genetics, The Institute of Medical Research Israel-Canada The Kuvin Center for the Study of Infectious and Tropical Diseases, Faculty of Medicine, The Hebrew University, Hadassah Medical School, Jerusalem, Israel.
| | - Habte Tekie
- Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Meshesha Balkew
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Alon Warburg
- Department of Microbiology and Molecular Genetics, The Institute of Medical Research Israel-Canada The Kuvin Center for the Study of Infectious and Tropical Diseases, Faculty of Medicine, The Hebrew University, Hadassah Medical School, Jerusalem, Israel.
| | - Asrat Hailu
- Department of Microbiology, Immunology and Parasitology, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Teshome Gebre-Michael
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.
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Gebresilassie A, Kirstein OD, Yared S, Aklilu E, Moncaz A, Tekie H, Balkew M, Warburg A, Hailu A, Gebre-Michael T. Nocturnal periodicity of Phlebotomus (Larroussius) orientalis (Diptera: Psychodidae) in an endemic focus of visceral leishmaniasis in Northern Ethiopia. Parasit Vectors 2015; 8:186. [PMID: 25889314 PMCID: PMC4381670 DOI: 10.1186/s13071-015-0804-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Accepted: 03/17/2015] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Phlebotomus orientalis is the major vector of the intramacrophage protozoa, Leishmania donovani, the etiological agent of visceral leishmaniasis (VL) in northern Ethiopia and Sudan. The objective of this study was to determine the nocturnal periodicity of P. orientalis in the VL endemic focus of Tahtay Adiyabo district, northern Ethiopia. METHODS Sandflies were collected using CDC light traps by changing collecting bags at an hourly interval from dusk to dawn for six months (January-June 2013) from outdoors (i.e. peri-domestic and agricultural fields). Sandfly specimens collected in the study were identified to species level and counted. RESULTS In total, 21,716 nocturnally active sandfly specimens, which belong to two genera (i.e., Phlebotomus and Sergentomyia) were collected and identified. In the collection, P. orientalis, the dominant species in the genus Phlebotomus, constituted 33.79% while Sergentomyia spp. comprised 65.44%. Analysis of data showed that activity of P. orientalis females increased from 18:00 to 24:00 hours, with a peak after midnight (24:00-03:00 hrs). Likewise, activity of parous P. orientalis females was found to be unimodal, peaking at 24-01:00 hrs. CONCLUSION P. orientalis females had marked nocturnal activity, which peak after midnight. Similarly, the epidemiologically dangerous parous females generally were more active after midnight. Therefore, humans are at risk of L. donovani infections through the bite of P. orientalis possibly between midnight and dawn.
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Affiliation(s)
- Araya Gebresilassie
- Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
- Department of Biology, College of Natural Science, Jigjiga University, Jigjiga, Ethiopia.
| | - Oscar David Kirstein
- Department of Microbiology and Molecular Genetics, The Institute of Medical Research Israel-Canada The Kuvin Center for the Study of Infectious and Tropical Diseases, Faculty of Medicine, The Hebrew University, Hadassah Medical School, Jerusalem, Israel.
| | - Solomon Yared
- Department of Biology, College of Natural Science, Jigjiga University, Jigjiga, Ethiopia.
| | - Essayas Aklilu
- Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Aviad Moncaz
- Department of Microbiology and Molecular Genetics, The Institute of Medical Research Israel-Canada The Kuvin Center for the Study of Infectious and Tropical Diseases, Faculty of Medicine, The Hebrew University, Hadassah Medical School, Jerusalem, Israel.
| | - Habte Tekie
- Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Meshesha Balkew
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Alon Warburg
- Department of Microbiology and Molecular Genetics, The Institute of Medical Research Israel-Canada The Kuvin Center for the Study of Infectious and Tropical Diseases, Faculty of Medicine, The Hebrew University, Hadassah Medical School, Jerusalem, Israel.
| | - Asrat Hailu
- Department of Microbiology, Immunology and Parasitology, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Teshome Gebre-Michael
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.
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Lemma W, Tekie H, Yared S, Balkew M, Gebre-Michael T, Warburg A, Hailu A. Sero-prevalence of Leishmania donovani infection in labour migrants and entomological risk factors in extra-domestic habitats of Kafta-Humera lowlands - kala-azar endemic areas in the northwest Ethiopia. BMC Infect Dis 2015; 15:99. [PMID: 25884167 PMCID: PMC4347912 DOI: 10.1186/s12879-015-0830-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 02/11/2015] [Indexed: 01/07/2023] Open
Abstract
Background Visceral leishmaniasis (VL) or kala-azar cases in seasonal labour migrants from highland areas are addressed to travel history to the Metema–Humera lowlands, northwestern Ethiopia. Factors that affect the incidence of VL in extra-domestic habitats were not evaluated. The aim of this study was to evaluate sero-prevalence of Leishmania donovani infection in randomly selected labour migrant workers and entomological risk factors which might affect the incidence of kala-azar. Methods Sero-prevalence of L. donovani infection in labour migrants was obtained from Direct Agglutination Test (DAT) using blood samples. Logistic regression analysis was used to correlate the possible risk factors with L. donovani infection. The season for L. donovani infection or Phlebotomus orientalis bite was estimated from the study of population dynamic of P. orientalis in areas where the blood was sampled. Result A total of 7, 443 P. orientalis (1,748 female and 5,695 male) were collected from agricultural fields and thickets of Acacia seyal using 461 CDC light traps. The highest mean number of P. orientalis/trap in the thickets of A. seyal and agricultural fields were 46.9 and 43.9 in March and April respectively. The mean P. orientalis/trap for November – May dry season in agricultural fields (11.39) and thickets of A. seyal (25.30) were higher compared to 0.66 in fields and 3.92 in thickets during June – August weeding season. Of the total 359 labour migrants screened using DAT, 45 (12.5%) were DAT-positive (≥1:800) for L. donovani infections. Very high titers (1:12800) were found in 3 (0.8%) individuals who had the risk of kala-azar development. Statistically significant p-values and odd ratio (OR) for staying in the areas both in the weeding and harvesting seasons (p = 0.035; OR = 2.83) and sleeping in the agricultural fields (p = 0.01; OR = 15.096) were positively correlated with L. donovani infection. Night harvest (p = 0.028; OR = 0.133) and knowledge about sign or symptoms (p = 0.042; OR = 0.383) were negatively associated with this infection. Conclusions Sleeping in open agricultural fields was related with L. donovani infections in labour migrants during June-August weeding season.
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Affiliation(s)
- Wossenseged Lemma
- Department of Medical Parasitology, School of Biomedical and Laboratory Sciences, College of Medicine and Health Sciences, University of Gondar, Gondar, Ethiopia. .,Department of Zoological Sciences, College of Natural Science, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Habte Tekie
- Department of Zoological Sciences, College of Natural Science, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Solomon Yared
- Department of Biology, College of Natural Science, Jigjiga University, Jigjiga, Ethiopia.
| | - Meshesha Balkew
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Teshome Gebre-Michael
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Alon Warburg
- Department of Microbiology and Molecular Genetics, The Institute for Medical Research Israel-Canada, The Kuvin Centre for the Study of Infectious & Tropical Diseases, The Hebrew University - Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, 91120, Israel.
| | - Asrat Hailu
- Department of Microbiology, Immunology & Parasitology, Faculty of Medicine, Addis Ababa University, Addis Ababa, Ethiopia.
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Gebresilassie A, Yared S, Aklilu E, Kirstein OD, Moncaz A, Tekie H, Balkew M, Warburg A, Hailu A, Gebre-Michael T. The influence of moonlight and lunar periodicity on the efficacy of CDC light trap in sampling Phlebotomus (Larroussius) orientalis Parrot, 1936 and other Phlebotomus sandflies (Diptera: Psychodidae) in Ethiopia. Parasit Vectors 2015; 8:106. [PMID: 25889659 PMCID: PMC4335511 DOI: 10.1186/s13071-015-0723-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 02/08/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Phlebotomus orientalis is the main sandfly vector of visceral leishmaniasis in the north and northwest of Ethiopia. CDC light traps and sticky traps are commonly used for monitoring sandfly populations. However, their trapping efficiency is greatly influenced by various environmental factors including moonlight and lunar periodicity. In view of that, the current study assessed the effect of moonlight and lunar periodicity on the performance of light traps in collecting P. orientalis. METHODS Trapping of P. orientalis and other Phlebotomus spp. was conducted for 7 months between December 2012 and June 2013 using CDC light traps and sticky traps from peri-domestic and agricultural fields. Throughout the trapping periods, collections of sandfly specimens were carried out for 4 nights per month, totaling 28 trapping nights that coincided with the four lunar phases (viz., first quarter, third quarter, new and full moon) distributed in each month. RESULTS In total, 13,533 sandflies of eight Phlebotomus species (P. orientalis, P. bergeroti, P. rodhaini, P. duboscqi, P. papatasi, P. martini, P. lesleyae and P. heischi) were recorded. The predominant species was P. orientalis in both trapping sites and by both methods of collection in all lunar phases. A significant difference (P < 0.05) was observed in the mean numbers of P. orientalis and other Phlebotomus spp. caught by CDC light traps among the four lunar phases. The highest mean number (231.13 ± 36.27 flies/trap/night) of P. orientalis was collected during the new moon phases, when the moonlight is absent. Fewer sandflies were attracted to light traps during a full moon. However, the number of P. orientalis and the other Phlebotomus spp. from sticky traps did not differ in their density among the four lunar phases (P = 0.122). CONCLUSION Results of the current study demonstrated that the attraction and trapping efficiency of CDC light traps is largely influenced by the presence moonlight, especially during a full moon. Therefore, sampling of sandflies using light traps to estimate population density and other epidemiological studies in the field should take the effect of moonlight and lunar periodicity into account on the trapping efficacy of light traps.
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Affiliation(s)
- Araya Gebresilassie
- Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
- Department of Biology, College of Natural Science, Jigjiga University, Jigjiga, Ethiopia.
| | - Solomon Yared
- Department of Biology, College of Natural Science, Jigjiga University, Jigjiga, Ethiopia.
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Essayas Aklilu
- Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Oscar David Kirstein
- Department of Microbiology and Molecular Genetics, The Institute of Medical Research Israel-Canada The Kuvin Center for the Study of Infectious and Tropical Diseases, Faculty of Medicine, The Hebrew University, Hadassah Medical School, Jerusalem, Israel.
| | - Aviad Moncaz
- Department of Microbiology and Molecular Genetics, The Institute of Medical Research Israel-Canada The Kuvin Center for the Study of Infectious and Tropical Diseases, Faculty of Medicine, The Hebrew University, Hadassah Medical School, Jerusalem, Israel.
| | - Habte Tekie
- Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Meshesha Balkew
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Alon Warburg
- Department of Microbiology and Molecular Genetics, The Institute of Medical Research Israel-Canada The Kuvin Center for the Study of Infectious and Tropical Diseases, Faculty of Medicine, The Hebrew University, Hadassah Medical School, Jerusalem, Israel.
| | - Asrat Hailu
- Department of Microbiology, Immunology and Parasitology, School of Medicine, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Teshome Gebre-Michael
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.
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Moncaz A, Kirstein O, Gebresellassie A, Lemma W, Yared S, Gebre-Michael T, Hailu A, Shenker M, Warburg A. Characterization of breeding sites of Phlebotomus orientalis - the vector of visceral leishmaniasis in northwestern Ethiopia. Acta Trop 2014; 139:5-14. [PMID: 25004440 DOI: 10.1016/j.actatropica.2014.06.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 06/24/2014] [Accepted: 06/27/2014] [Indexed: 11/17/2022]
Abstract
We studied breeding sites of Phlebotomus orientalis (Diptera: Psychodidae) the vector of visceral leishmaniasis in northern Ethiopia. Although numbers were rather small, 165 sand flies were captured emerging from vertisol cracks. The most productive breeding sites were cracked vertisols, dry river banks and close to trees. No sand flies were caught emerging from sandy clay loam soils in peri-domestic habitats but a few were captured emerging from gaps in a stone wall. Abiotic parameters in vertisols close to trees and in open field from which P. orientalis had emerged, were compared. Soil pH was slightly alkaline and salinity was low. Organic matter contents were similar in both sites. Temperatures and RH remained relatively stable near trees from the end of the rainy season through mid dry season, yet fluctuated markedly at the shallower depth in the open field. During the rainy season, cracks in the soil were sealed resulting in significant lowering of the oxygen concentrations near the tree. Gravimetric water content of soil near trees was lower than open field at shallow depth but similar deeper down. We conclude that ambient conditions suitable for sand fly larvae at shallow depths (45cm) are restricted to areas close to trees. However, deeper in vertisols (90cm) suitable conditions are apparently maintained throughout the dry season even in open fallow fields.
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Affiliation(s)
- Aviad Moncaz
- The Kuvin Center for the Study of Infectious and Tropical Diseases, Department of Microbiology and Molecular Genetics, The Institute of Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Hadassah Medical School, Jerusalem, Israel; Department of Soil and Water, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Oscar Kirstein
- The Kuvin Center for the Study of Infectious and Tropical Diseases, Department of Microbiology and Molecular Genetics, The Institute of Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Hadassah Medical School, Jerusalem, Israel
| | - Araya Gebresellassie
- Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Wossenseged Lemma
- Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Solomon Yared
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
| | - Teshome Gebre-Michael
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
| | - Asrat Hailu
- Department of Microbiology, Immunology & Parasitology, Faculty of Medicine, Addis Ababa University, Addis Ababa, Ethiopia
| | - Moshe Shenker
- Department of Soil and Water, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, Israel
| | - Alon Warburg
- The Kuvin Center for the Study of Infectious and Tropical Diseases, Department of Microbiology and Molecular Genetics, The Institute of Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Hadassah Medical School, Jerusalem, Israel.
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Yared S, Deribe K, Gebreselassie A, Lemma W, Akililu E, Kirstein OD, Balkew M, Warburg A, Gebre-Michael T, Hailu A. Risk factors of visceral leishmaniasis: a case control study in north-western Ethiopia. Parasit Vectors 2014; 7:470. [PMID: 25312308 PMCID: PMC4205297 DOI: 10.1186/s13071-014-0470-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 10/01/2014] [Indexed: 11/10/2022] Open
Abstract
Background Visceral leishmaniasis (VL, also called ‘’kala-azar”), is a life threatening neglected tropical infectious disease which mainly affects the poorest of the poor. VL is prevalent in Ethiopia particularly in the northwest of the country. Understanding the risk factors of VL infection helps in its prevention and control. The aim of the present study was to identify the factors associated with VL. Methods A case–control study was carried out during the period of January-July 2013 in northwest Ethiopia. Cases and controls were diagnosed using clinical presentation, the rk39 rapid diagnostic test and Direct Agglutination Test (DAT). A total of 283 (84.8% males versus 15.2% females) participants were interviewed. 90 cases and 193 controls were involved, matched by age, sex and geographical location with a ratio of 1:2 (case: controls). Univariate and backward multivariate conditional logistic regression were used to identify risk factors of VL. Results Elevated odds of VL was associated with goat ownership (OR = 6.4; 95%: confidence interval [Cl]: 1.5-28.4), living in houses with cracked wall (OR = 6.4; 95% Cl: 1.6-25.6), increased family size (OR = 1.3; 95% Cl: 1.0-1.8) and the number of days spent in the farm field (OR = 1.1; 95% Cl: 1.0-1.2). However, daily individual activities around the home and farm fields, mainly sleeping on a bed (OR = 0.2; 95%: Cl 0.03-0.9), sleeping outside the house under a bed net (OR = 0.1; 95% Cl: 0.02-0.36)] and smoking plant parts in the house during the night time (OR = 0.1; 95% Cl: 0.01-0.6) were associated with decreased odds of being VL case. Conclusion Our findings showed that use of bed net and smoke could be helpful for the prevention of VL in the area particularly among individuals who spend most of their time in the farm. VL control effort could be focused on improving housing conditions, such as sealing cracks and crevices inside and outside houses. Further research is warranted to elucidate the role of goats in the transmission of L. donovani, assess the impact of bed nets and the role of the traditional practice of smoking plants.
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Affiliation(s)
- Solomon Yared
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia. .,Department of Biology, College of Natural Science, Jigjiga University, Jigjiga, Ethiopia.
| | - Kebede Deribe
- Brighton & Sussex Medical School, Falmer, Brighton, UK. .,School of Public Health, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Araya Gebreselassie
- Department of Biology, College of Natural Science, Jigjiga University, Jigjiga, Ethiopia. .,School of Public Health, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Wessenseged Lemma
- Department of Zoological Science, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Essayas Akililu
- Department of Zoological Science, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Oscar D Kirstein
- Department of Microbiology and Molecular Genetics, The Institute of Medical Research Israel-Canada The Kuvin Center for the Study of Infectious and Tropical Diseases, Faculty of Medicine, The Hebrew University, Hadassah Medical School, Jerusalem, Israel.
| | - Meshesha Balkew
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Alon Warburg
- Department of Microbiology and Molecular Genetics, The Institute of Medical Research Israel-Canada The Kuvin Center for the Study of Infectious and Tropical Diseases, Faculty of Medicine, The Hebrew University, Hadassah Medical School, Jerusalem, Israel.
| | - Teshome Gebre-Michael
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia.
| | - Asrat Hailu
- Department of Microbiology, Immunology and Parasitology, Faculty of Medicine, Addis Ababa University, Addis Ababa, Ethiopia.
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Attum AA, Girardet R, Barbie R, Yared S, Raleigh D, Mathew T, Hymes W, Lansing A. Risks of cerebrovascular events related to open heart surgery. J Ky Med Assoc 1998; 96:290-5. [PMID: 9735641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Prevention of perioperative cerebrovascular injury in patients undergoing open heart surgery is a serious task for the surgeon, especially as age and severity of atherosclerotic disease increases. The most significant predisposing factors have been identified as existing carotid arterial disease or prior stroke, heavy calcification of the aorta, renal dysfunction, advanced age, and diabetes mellitus. We have studied a series of 600 open heart patients from 1992 to 1995 from the incidence of peri-operative stroke and mortality, evaluating 16 risk factors: heavy calcification of the ascending aorta, asymptomatic carotid disease, insulin-dependent diabetes mellitus, prior CVA, left ventricular function (ejection fraction of 20% or less), age greater than 70, renal dysfunction, transmural myocardial infarction, fluid balance index greater than 2500 ccs, smoking, type of procedure, emergency procedure, non-insulin-dependent diabetes mellitus, cardiopulmonary bypass time, gender, and hypertension Stroke occurred in 8 patients (1.3%), one of whom die postoperatively. Full or near-full recovery was experienced by 5 patients; 2 patients remained partially dysfunctional at the end of the study period. The operative mortality was 2.0% (12 patients); 10 deaths occurred in hospital and 2 following discharge within 30 days postoperatively. The risk of stroke was 15 times greater in patients over age 70; 16 times greater in older males (> or = 70 years); 5 times greater in patients with prior stroke or existing (asymptomatic) carotid artery disease; 8 times greater in patients with renal dysfunction; 4 times greater with a positive fluid balance index; and twice greater when cardiopulmonary bypass exceeded 110 minutes. Four of the stroke patients had diabetes mellitus. Two of 9 patients with heavy calcification of the aortic arch suffered cerebrovascular injury. Six or more of the risk factors studied were present in 81 patients; all 8 stroke patients (9.9%) came from this subgroup. The study suggests the importance of pre-operative evaluation of cerebrovascular atherosclerotic disease and the minimal manipulation ("minimal touch" technique) of a calcific aortic arch.
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Affiliation(s)
- A A Attum
- Department of Cardiovascular Surgery, Audubon Regional Medical Center, Louisville, KY, USA
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Girardet RE, Masri ZH, Barbie RN, Attum AA, Yared S, DeVries WC, Lansing AM. Vein graft arteriovenous fistula for long-term venous access in a heart transplant recipient lacking superficial veins: a case report. J Heart Transplant 1986; 5:484-5. [PMID: 3302183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Construction of a (radial artery) saphenous vein graft arteriovenous fistula for blood sampling after heart transplantation is presented as a solution to the problem of a patient with poor or sclerosed superficial arm veins. Satisfactory experience with one patient over a 12.5 month follow-up is presented.
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