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Balam S, Miura K, Ayadi I, Konaté D, Incandela NC, Agnolon V, Guindo MA, Diakité SA, Olugbile S, Nebie I, Herrera SM, Long C, Kajava AV, Diakité M, Corradin G, Herrera S, Herrera MA. Cross-reactivity of r Pvs48/45, a recombinant Plasmodium vivax protein, with sera from Plasmodium falciparum endemic areas of Africa. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.10.588966. [PMID: 38659832 PMCID: PMC11042229 DOI: 10.1101/2024.04.10.588966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Background Ps48/45, a Plasmodium gametocyte surface protein, is a promising candidate for malaria transmission-blocking (TB) vaccine. Due to its relevance for a multispecies vaccine, we explored the cross-reactivity and TB activity of a recombinant P. vivax Ps48/45 protein (rPvs48/45) with sera from P. falciparum-exposed African donors. Methods rPvs48/45 was produced in Chinese hamster ovary cell lines and tested by ELISA for its cross-reactivity with sera from Burkina Faso, Tanzania, Mali, and Nigeria - In addition, BALB/c mice were immunized with the rPvs48/45 protein formulated in Montanide ISA-51 and inoculated with a crude extract of P. falciparum NF-54 gametocytes to evaluate the parasite-boosting effect on rPvs48/45 antibody titers. Specific anti-rPvs48/45 IgG purified from African sera was used to evaluate the ex vivo TB activity on P. falciparum, using standard mosquito membrane feeding assays (SMFA). Results rPvs48/45 protein showed cross-reactivity with sera of individuals from all four African countries, in proportions ranging from 94% (Tanzania) to 40% (Nigeria). Also, the level of cross-reactive antibodies varied significantly between countries (p<0.0001), with a higher antibody level in Mali and the lowest in Nigeria. In addition, antibody levels were higher in adults (≥ 17 years) than young children (≤ 5 years) in both Mali and Tanzania, with a higher proportion of responders in adults (90%) than in children (61%) (p<0.0001) in Mali, where male (75%) and female (80%) displayed similar antibody responses. Furthermore, immunization of mice with P. falciparum gametocytes boosted anti-Pvs48/45 antibody responses, recognizing P. falciparum gametocytes in indirect immunofluorescence antibody test. Notably, rPvs48/45 affinity-purified African IgG exhibited a TB activity of 61% against P. falciparum in SMFA. Conclusion African sera (exposed only to P. falciparum) cross-recognized the rPvs48/45 protein. This, together with the functional activity of IgG, warrants further studies for the potential development of a P. vivax and P. falciparum cross-protective TB vaccine.
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Affiliation(s)
- Saidou Balam
- International Center for Excellence in Research (ICER-Mali), University of Sciences, Techniques and Technologies of Bamako (USTTB), Bamako, Mali
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
| | - Imen Ayadi
- Immunobiology Department, University of Lausanne, Lausanne, Switzerland
| | - Drissa Konaté
- International Center for Excellence in Research (ICER-Mali), University of Sciences, Techniques and Technologies of Bamako (USTTB), Bamako, Mali
| | | | - Valentina Agnolon
- Division of Immunology and Allergy, Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland aaaa
| | - Merepen A Guindo
- International Center for Excellence in Research (ICER-Mali), University of Sciences, Techniques and Technologies of Bamako (USTTB), Bamako, Mali
| | - Seidina A.S. Diakité
- International Center for Excellence in Research (ICER-Mali), University of Sciences, Techniques and Technologies of Bamako (USTTB), Bamako, Mali
| | - Sope Olugbile
- Immunobiology Department, University of Lausanne, Lausanne, Switzerland
| | - Issa Nebie
- Groupe de Recherche Action Santé (GRAS), Burkina Faso, West Africa
| | | | - Carole Long
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
| | - Andrey V. Kajava
- Montpellier Cell Biology Research Center (CRBM), University of Montpellier, CNRS, France
| | - Mahamadou Diakité
- International Center for Excellence in Research (ICER-Mali), University of Sciences, Techniques and Technologies of Bamako (USTTB), Bamako, Mali
| | | | - Socrates Herrera
- Caucaseco Scientific Research Center, Cali, Colombia
- Malaria Vaccine and Drug Development Center, Cali, Colombia
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Ashine T, Eyasu A, Asmamaw Y, Simma E, Zemene E, Epstein A, Brown R, Negash N, Kochora A, Reynolds AM, Bulto MG, Tafesse T, Dagne A, Lukus B, Esayas E, Behaksra SW, Woldekidan K, Kassa FA, Deressa JD, Assefa M, Dillu D, Assefa G, Solomon H, Zeynudin A, Massebo F, Sedda L, Donnelly MJ, Wilson AL, Weetman D, Gadisa E, Yewhalaw D. Spatiotemporal distribution and bionomics of Anopheles stephensi in different eco-epidemiological settings in Ethiopia. Parasit Vectors 2024; 17:166. [PMID: 38556881 PMCID: PMC10983662 DOI: 10.1186/s13071-024-06243-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 03/11/2024] [Indexed: 04/02/2024] Open
Abstract
BACKGROUND Malaria is a major public health concern in Ethiopia, and its incidence could worsen with the spread of the invasive mosquito species Anopheles stephensi in the country. This study aimed to provide updates on the distribution of An. stephensi and likely household exposure in Ethiopia. METHODS Entomological surveillance was performed in 26 urban settings in Ethiopia from 2021 to 2023. A kilometer-by-kilometer quadrant was established per town, and approximately 20 structures per quadrant were surveyed every 3 months. Additional extensive sampling was conducted in 50 randomly selected structures in four urban centers in 2022 and 2023 to assess households' exposure to An. stephensi. Prokopack aspirators and CDC light traps were used to collect adult mosquitoes, and standard dippers were used to collect immature stages. The collected mosquitoes were identified to species level by morphological keys and molecular methods. PCR assays were used to assess Plasmodium infection and mosquito blood meal source. RESULTS Catches of adult An. stephensi were generally low (mean: 0.15 per trap), with eight positive sites among the 26 surveyed. This mosquito species was reported for the first time in Assosa, western Ethiopia. Anopheles stephensi was the predominant species in four of the eight positive sites, accounting for 75-100% relative abundance of the adult Anopheles catches. Household-level exposure, defined as the percentage of households with a peridomestic presence of An. stephensi, ranged from 18% in Metehara to 30% in Danan. Anopheles arabiensis was the predominant species in 20 of the 26 sites, accounting for 42.9-100% of the Anopheles catches. Bovine blood index, ovine blood index and human blood index values were 69.2%, 32.3% and 24.6%, respectively, for An. stephensi, and 65.4%, 46.7% and 35.8%, respectively, for An. arabiensis. None of the 197 An. stephensi mosquitoes assayed tested positive for Plasmodium sporozoite, while of the 1434 An. arabiensis mosquitoes assayed, 62 were positive for Plasmodium (10 for P. falciparum and 52 for P. vivax). CONCLUSIONS This study shows that the geographical range of An. stephensi has expanded to western Ethiopia. Strongly zoophagic behavior coupled with low adult catches might explain the absence of Plasmodium infection. The level of household exposure to An. stephensi in this study varied across positive sites. Further research is needed to better understand the bionomics and contribution of An. stephensi to malaria transmission.
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Affiliation(s)
- Temesgen Ashine
- Department of Biology, College of Natural and Computational Sciences, Arba Minch University, Arba Minch, Ethiopia.
- Malaria and NTD Research Division, Armauer Hansen Research Institute, Addis Ababa, Ethiopia.
| | - Adane Eyasu
- Tropical and Infectious Diseases Research Center, Jimma University, Jimma, Ethiopia
| | - Yehenew Asmamaw
- Malaria and NTD Research Division, Armauer Hansen Research Institute, Addis Ababa, Ethiopia
| | - Eba Simma
- Department of Biology, College of Natural Sciences, Jimma University, Jimma, Ethiopia
| | - Endalew Zemene
- School of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia
| | - Adrienne Epstein
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Rebecca Brown
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Nigatu Negash
- Malaria and NTD Research Division, Armauer Hansen Research Institute, Addis Ababa, Ethiopia
| | - Abena Kochora
- Malaria and NTD Research Division, Armauer Hansen Research Institute, Addis Ababa, Ethiopia
| | - Alison M Reynolds
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | | | - Temesgen Tafesse
- Malaria and NTD Research Division, Armauer Hansen Research Institute, Addis Ababa, Ethiopia
| | - Alemayehu Dagne
- Tropical and Infectious Diseases Research Center, Jimma University, Jimma, Ethiopia
| | - Biniyam Lukus
- Tropical and Infectious Diseases Research Center, Jimma University, Jimma, Ethiopia
| | - Endashaw Esayas
- Malaria and NTD Research Division, Armauer Hansen Research Institute, Addis Ababa, Ethiopia
| | | | - Kidist Woldekidan
- Malaria and NTD Research Division, Armauer Hansen Research Institute, Addis Ababa, Ethiopia
| | | | - Jimma Dinsa Deressa
- Malaria and NTD Research Division, Armauer Hansen Research Institute, Addis Ababa, Ethiopia
| | - Muluken Assefa
- Malaria and NTD Research Division, Armauer Hansen Research Institute, Addis Ababa, Ethiopia
| | - Dereje Dillu
- Disease Prevention and Control Directorate, Ethiopian Federal Ministry of Health, Addis Ababa, Ethiopia
| | - Gudissa Assefa
- Disease Prevention and Control Directorate, Ethiopian Federal Ministry of Health, Addis Ababa, Ethiopia
| | - Hiwot Solomon
- Disease Prevention and Control Directorate, Ethiopian Federal Ministry of Health, Addis Ababa, Ethiopia
| | - Ahmed Zeynudin
- School of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia
| | - Fekadu Massebo
- Department of Biology, College of Natural and Computational Sciences, Arba Minch University, Arba Minch, Ethiopia
| | - Luigi Sedda
- Lancaster Ecology and Epidemiology Group, Lancaster Medical School, Lancaster University, Lancaster, UK
| | - Martin James Donnelly
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Anne L Wilson
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - David Weetman
- Department of Vector Biology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, L3 5QA, UK
| | - Endalamaw Gadisa
- Malaria and NTD Research Division, Armauer Hansen Research Institute, Addis Ababa, Ethiopia
| | - Delenasaw Yewhalaw
- Tropical and Infectious Diseases Research Center, Jimma University, Jimma, Ethiopia
- School of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia
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Abossie A, Demissew A, Getachew H, Tsegaye A, Degefa T, Habtamu K, Zhong D, Wang X, Lee MC, Zhou G, King CL, Kazura JW, Yan G, Yewhalaw D. Higher outdoor mosquito density and Plasmodium infection rates in and around malaria index case households in low transmission settings of Ethiopia: Implications for vector control. Parasit Vectors 2024; 17:53. [PMID: 38321572 PMCID: PMC10848356 DOI: 10.1186/s13071-023-06088-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 12/07/2023] [Indexed: 02/08/2024] Open
Abstract
BACKGROUND Understanding the clustering of infections for persistent malaria transmission is critical to determining how and where to target specific interventions. This study aimed to determine the density, blood meal sources and malaria transmission risk of anopheline vectors by targeting malaria index cases, their neighboring households and control villages in Arjo-Didessa, southwestern Ethiopia. METHODS An entomological study was conducted concurrently with a reactive case detection (RCD) study from November 2019 to October 2021 in Arjo Didessa and the surrounding vicinity, southwestern Ethiopia. Anopheline mosquitoes were collected indoors and outdoors in index case households and their surrounding households (neighboring households), as well as in control households, using pyrethrum spray cache (PSC) and U.S. Centers for Disease Control and Prevention (CDC) light traps. Adult mosquitoes were morphologically identified, and speciation in the Anopheles gambiae complex was done by PCR. Mosquito Plasmodium infections and host blood meal sources were detected by circumsporozoite protein enzyme-linked immunosorbent assay (CSP-ELISA) and cytochrome b-based blood meal PCR, respectively. RESULTS Among the 770 anopheline mosquitoes collected, An. gambiae sensu lato (A. gambiae s.l.) was the predominant species, accounting for 87.1% (n = 671/770) of the catch, followed by the Anopheles coustani complex and Anopheles pharoensis, which accounted for 12.6% (n = 97/770) and 0.26% (n = 2/770) of the catch, respectively. From the sub-samples of An. gambiae s.l.analyzed with PCR, An. arabiensis and Anopheles amharicus were identified. The overall mean density of mosquitoes was 1.26 mosquitoes per trap per night using the CDC light traps. Outdoor mosquito density was significantly higher than indoor mosquito density in the index and neighboring households (P = 0.0001). The human blood index (HBI) and bovine blood index (BBI) of An. arabiensis were 20.8% (n = 34/168) and 24.0% (n = 41/168), respectively. The overall Plasmodium sporozoite infection rate of anophelines (An. arabiensis and An. coustani complex) was 4.4% (n = 34/770). Sporozoites were detected indoors and outdoors in captured anopheline mosquitoes. Of these CSP-positive species for Pv-210, Pv-247 and Pf, 41.1% (n = 14/34) were captured outdoors. A significantly higher proportion of sporozoite-infected mosquitoes were caught in index case households (5.6%, n = 8/141) compared to control households (1.1%, n = 2/181) (P = 0.02), and in neighboring households (5.3%, n = 24/448) compared to control households (P = 0.01). CONCLUSIONS The findings of this study indicated that malaria index cases and their neighboring households had higher outdoor mosquito densities and Plasmodium infection rates. The study also highlighted a relatively higher outdoor mosquito density, which could increase the potential risk of outdoor malaria transmission and may play a role in residual malaria transmission. Thus, it is important to strengthen the implementation of vector control interventions, such as targeted indoor residual spraying, long-lasting insecticidal nets and other supplementary vector control measures such as larval source management and community engagement approaches. Furthermore, in low transmission settings, such as the Arjo Didessa Sugarcane Plantation, providing health education to local communities, enhanced environmental management and entomological surveillance, along with case detection and management by targeting of malaria index cases and their immediate neighboring households, could be important measures to control residual malaria transmission and achieve the targeted elimination goals.
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Affiliation(s)
- Ashenafi Abossie
- Department of Medical Laboratory Sciences, College of Medicine and Health Sciences, Arba Minch University, Arba Minch, Ethiopia.
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia.
- Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia.
| | - Assalif Demissew
- Department of Medical Laboratory Sciences, College of Medicine and Health Sciences, Ambo University, Ambo, Ethiopia
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
- Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
| | - Hallelujah Getachew
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia
- Department of Medical Laboratory Technology, Arba Minch College of Health Sciences, Arba Minch, Ethiopia
- Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
| | - Arega Tsegaye
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia
- Department of Biology, College of Natural Science, Jimma University, Jimma, Ethiopia
- Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
| | - Teshome Degefa
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia
- Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
| | - Kassahun Habtamu
- Menelik II College of Health Sciences, Addis Ababa, Ethiopia
- Department of Microbial, Cellular and Molecular Biology, College of Natural Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Daibin Zhong
- Program in Public Health, University of California at Irvine, Irvine, CA, 92697, USA
| | - Xiaoming Wang
- Program in Public Health, University of California at Irvine, Irvine, CA, 92697, USA
| | - Ming-Chieh Lee
- Program in Public Health, University of California at Irvine, Irvine, CA, 92697, USA
| | - Guofa Zhou
- Program in Public Health, University of California at Irvine, Irvine, CA, 92697, USA
| | - Christopher L King
- Center for Global Health & Diseases, School of Medicine, Case Western Reserve University, Cleveland, 44106 OH, USA
| | - James W Kazura
- Center for Global Health & Diseases, School of Medicine, Case Western Reserve University, Cleveland, 44106 OH, USA
| | - Guiyun Yan
- Program in Public Health, University of California at Irvine, Irvine, CA, 92697, USA
| | - Delenasaw Yewhalaw
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia
- Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
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Real-Jaramillo S, Bustillos JJ, Moncayo AL, Neira M, Fárez L, Beltrán E, Ocaña-Mayorga S. Phenotypic resistance not associated with knockdown mutations (kdr) in Anopheles albimanus exposed to deltamethrin in southern coastal Ecuador. Malar J 2024; 23:17. [PMID: 38217047 PMCID: PMC10787486 DOI: 10.1186/s12936-023-04818-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 12/08/2023] [Indexed: 01/14/2024] Open
Abstract
BACKGROUND Decrease in malaria rates (e.g. incidence and cases) in Latin America maintains this region on track to achieve the goal of elimination. During the last 5 years, three countries have been certified as malaria free. However, the region fails to achieve the goal of 40% reduction on malaria rates and an increase of cases has been reported in some countries, including Ecuador. This scenario has been associated with multiple causes, such as decrease of funding to continue anti-malarial programmes and the development of insecticide resistance of the main malaria vectors. In Ecuador, official reports indicated phenotypic resistance in Aedes aegypti and Anopheles albimanus to deltamethrin and malathion, particularly in the coastal areas of Ecuador, however, information about the mechanisms of resistance have not been yet elucidated. This study aims to evaluate phenotypic response to deltamethrin and its relationship with kdr mutations in An. albimanus from two localities with different agricultural activities in southern coastal Ecuador. METHODS The CDC bottle assay was carried out to evaluate the phenotypic status of the mosquito's population. Sequencing the voltage gated sodium channel gene (VGSC) sought knockdown mutations (kdr) in codons 1010, 1013 and 1014 associated with resistance. RESULTS Phenotypic resistance was found in Santa Rosa (63.3%) and suspected resistance in Huaquillas (82.1%); with females presenting a higher median of knockdown rate (83.7%) than males (45.6%). No statistical differences were found between the distributions of knockdown rate for the two localities (p = 0.6048) which indicates no influence of agricultural activity. Although phenotypic resistance was confirmed, genetic analysis demonstrate that this resistance was not related with the kdr mechanism of the VGSC gene because no mutations were found in codons 1010 and 1013, while in codon 1014, 90.6% showed the susceptible sequence (TTG) and 7.3% ambiguous nucleotides (TKK and TYG). CONCLUSIONS These results highlighted the importance of continuous monitoring of resistance in malaria vectors in Ecuador, particularly in areas that have reported outbreaks during the last years. It is also important to elucidate the mechanism involved in the development of the resistance to PYs to propose alternative insecticides or strategies for vector control in areas where resistance is present.
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Affiliation(s)
- Sebasthian Real-Jaramillo
- Centro de Investigación para la Salud en América Latina, Pontificia Universidad Católica del Ecuador, Calle Pambacienda y San Pedro del Valle, Campus Nayón, 170530, Nayón, Ecuador
| | - Juan J Bustillos
- Centro de Investigación para la Salud en América Latina, Pontificia Universidad Católica del Ecuador, Calle Pambacienda y San Pedro del Valle, Campus Nayón, 170530, Nayón, Ecuador
| | - Ana L Moncayo
- Centro de Investigación para la Salud en América Latina, Pontificia Universidad Católica del Ecuador, Calle Pambacienda y San Pedro del Valle, Campus Nayón, 170530, Nayón, Ecuador
| | - Marco Neira
- Centro de Investigación para la Salud en América Latina, Pontificia Universidad Católica del Ecuador, Calle Pambacienda y San Pedro del Valle, Campus Nayón, 170530, Nayón, Ecuador
- The Cyprus Institute, Climate and Atmosphere Research Center (CARE-C), Nicosia, Cyprus
| | - Leonardo Fárez
- Laboratorio de Referencia Intermedio de Entomología CZ707D02, Ministerio de Salud Pública de Ecuador, Machala, Ecuador
| | - Efraín Beltrán
- Unidad Académica de Ciencias Químicas y de La Salud, Universidad Técnica de Machala, Machala, Ecuador
| | - Sofía Ocaña-Mayorga
- Centro de Investigación para la Salud en América Latina, Pontificia Universidad Católica del Ecuador, Calle Pambacienda y San Pedro del Valle, Campus Nayón, 170530, Nayón, Ecuador.
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Getachew H, Demissew A, Abossie A, Habtamu K, Wang X, Zhong D, Zhou G, Lee MC, Hemming-Schroeder E, Bradley L, Degefa T, Hawaria D, Tsegaye A, W Kazura J, Koepfli C, Yan G, Yewhalaw D. Asymptomatic and submicroscopic malaria infections in sugar cane and rice development areas of Ethiopia. Malar J 2023; 22:341. [PMID: 37940948 PMCID: PMC10634149 DOI: 10.1186/s12936-023-04762-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 10/22/2023] [Indexed: 11/10/2023] Open
Abstract
BACKGROUND Water resource development projects, such as dams and irrigation schemes, have a positive impact on food security and poverty reduction. However, such projects could increase prevalence of vector borne disease, such as malaria. This study investigate the impact of different agroecosystems and prevalence of malaria infection in Southwest Ethiopia. METHODS Two cross-sectional surveys were conducted in the dry and wet seasons in irrigated and non-irrigated clusters of Arjo sugarcane and Gambella rice development areas of Ethiopia in 2019. A total of 4464 and 2176 study participants from 1449 households in Arjo and 546 households in Gambella enrolled in the study and blood samples were collected, respectively. All blood samples were microscopically examined and a subset of microscopy negative blood samples (n = 2244) were analysed by qPCR. Mixed effect logistic regression and generalized estimating equation were used to determine microscopic and submicroscopic malaria infection and the associated risk factors, respectively. RESULTS Prevalence by microscopy was 2.0% (88/4464) in Arjo and 6.1% (133/2176) in Gambella. In Gambella, prevalence was significantly higher in irrigated clusters (10.4% vs 3.6%) than in non-irrigated clusters (p < 0.001), but no difference was found in Arjo (2.0% vs 2.0%; p = 0.993). On the other hand, of the 1713 and 531 samples analysed by qPCR from Arjo and Gambella the presence of submicroscopic infection was 1.2% and 12.8%, respectively. Plasmodium falciparum, Plasmodium vivax, and Plasmodium ovale were identified by qPCR in both sites. Irrigation was a risk factor for submicroscopic infection in both Arjo and Gambella. Irrigation, being a migrant worker, outdoor job, < 6 months length of stay in the area were risk factors for microscopic infection in Gambella. Moreover, school-age children and length of stay in the area for 1-3 years were significant predictors for submicroscopic malaria in Gambella. However, no ITN utilization was a predictor for both submicroscopic and microscopic infection in Arjo. Season was also a risk factor for microscopic infection in Arjo. CONCLUSION The study highlighted the potential importance of different irrigation practices impacting on submicroscopic malaria transmission. Moreover, microscopic and submicroscopic infections coupled with population movement may contribute to residual malaria transmission and could hinder malaria control and elimination programmes in the country. Therefore, strengthening malaria surveillance and control by using highly sensitive diagnostic tools to detect low-density parasites, screening migrant workers upon arrival and departure, ensuring adequate coverage and proper utilization of vector control tools, and health education for at-risk groups residing or working in such development corridors is needed.
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Affiliation(s)
- Hallelujah Getachew
- Department of Medical Laboratory Technology, Arbaminch College of Health Sciences, Arbaminch, Ethiopia.
- Department of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia.
- Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia.
| | - Assalif Demissew
- Department of Medical Laboratory Sciences, College of Medicine and Health Sciences, Ambo University, Ambo, Ethiopia
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
| | - Ashenafi Abossie
- Department of Medical Laboratory Sciences, College of Medicine and Health Science, Arbaminch University, Arbaminch, Ethiopia
- Department of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia
- Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
| | - Kassahun Habtamu
- Menelik II Medical & Health Science College, Addis Ababa, Ethiopia
- Department of Microbial, Cellular & Molecular Biology, Addis Ababa University, Addis Ababa, Ethiopia
| | - Xiaoming Wang
- Program in Public Health, University of California at Irvine, Irvine, CA92697, USA
| | - Daibin Zhong
- Program in Public Health, University of California at Irvine, Irvine, CA92697, USA
| | - Guofa Zhou
- Program in Public Health, University of California at Irvine, Irvine, CA92697, USA
| | - Ming-Chieh Lee
- Program in Public Health, University of California at Irvine, Irvine, CA92697, USA
| | - Elizabeth Hemming-Schroeder
- Center for Vector Born Infectious Diseases (CVID), Department of Microbiology Immunology and Pathology, Colorado State University, Fort Collins, USA
| | - Lauren Bradley
- Program in Public Health, University of California at Irvine, Irvine, CA92697, USA
| | - Teshome Degefa
- Department of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia
| | - Dawit Hawaria
- School of Environmental Health, Hawassa University, Hawassa, Ethiopia
| | - Arega Tsegaye
- Department of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia
- Department of Biology, College of Natural Science, Jimma University, Jimma, Ethiopia
- Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
| | - James W Kazura
- Biomedical Research Case Western Reserve University, Cleveland, OH, USA
- Center for Global Health & Disease School of Medicine Case, Western Reserve University, Cleveland, OH, USA
| | - Cristian Koepfli
- Department of Biological Sciences 319 Galvin Life Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, USA
| | - Guiyun Yan
- Program in Public Health, University of California at Irvine, Irvine, CA92697, USA
| | - Delenasaw Yewhalaw
- Department of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia
- Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
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Zerdo Z, Bastiaens H, Anthierens S, Massebo F, Masne M, Biresaw G, Shewangizaw M, Tunje A, Chisha Y, Yohannes T, Van Geertruyden JP. Effect of malaria prevention education on bed net utilization, incidence of malaria and treatment seeking among school-aged children in Southern Ethiopia; cluster randomized controlled trial. BMC Infect Dis 2023; 23:486. [PMID: 37474930 PMCID: PMC10360348 DOI: 10.1186/s12879-023-08464-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 07/15/2023] [Indexed: 07/22/2023] Open
Abstract
BACKGROUND School-aged children (SAC) have an increased risk to contract malaria and play a major role in its transmission dynamics. However, their malaria prevention experience is poor. Thus, the effect of malaria prevention education (MPE) on bed net utilization, treatment seeking from a health facility and cumulative incidence of malaria was evaluated in Southern Ethiopia. METHODS A two arm cluster randomized controlled trial was conducted by recruiting 2038 SAC from 32 schools. Structured questionnaire was used to collect data on socio-demographic, economic, bed net ownership, bed net utilization, whether the participated child suffered from malaria and has got treatment from a health facility. Generalized mixed effect logistic regression using school as random variable was used to assess the effect of the intervention on the outcome variables. RESULTS The ownership of bed net in households of the control and intervention schools was similar respectively with 84.6 and 88.6% (Crude Odds Ratio (COR): 1.5; 95%CI: 0.5-4.8). The percentage of SAC slept under the bed net the night before the survey was also similar (55.1% versus 54.0%); COR:1.04; 95%CI: 0.5-2.4). Bed net utilization was affected by household size to the bed net ratio ≤ 2 (Adjusted Odds Ratio (AOR) = 1.6; 95%CI:1.3-2.1), bed net utilization at baseline of the study (AOR = 2.3; 95%CI:1.5-3.6), and history of malaria attack in the last twelve months (AOR = 1.3; 95%CI:1.01-1.8). Reported cumulative incidence of malaria and treatment seeking from a health facility by SAC was similar between intervention and control arms: -2.1% (COR = 0.8; 95%CI: 0.5-1.5) and 9.6% (COR = 1.4; 95%CI: 0.4-4.3) respectively. The reported incidence of malaria was affected by altitude (AOR = 0.5; 95%CI: 0.3-0.8), low and medium wealth index (AOR = 0.7; 95%CI: 0.5-0.96 and AOR = 0.7; 95%CI: 0.5-0.98), adequate bed net number for household members (AOR = 0.7; 95%CI:0.5-0.9) and bed net utilization (AOR = 1.3; 95%CI:1.1-1.8). CONCLUSIONS MPE had no significant effect on the use of malaria prevention measures considered, treatment seeking from a health facility and reported cumulative incidence of malaria though bed net use was associated with malaria incidence. Before organizing any health education program, sustainable implementation efforts have to be warranted especially in SAC, a neglected but relevant vulnerable and reservoirs. TRIAL REGISTRATION Pan African Clinical Trials Registry PACTR202001837195738, registered 21/01/2020.
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Affiliation(s)
- Zerihun Zerdo
- Department of Medical Laboratory Science, College of Medicine and Health Sciences, Arba Minch University, Arba Minch, Ethiopia.
- Global Health Institute, Antwerp University, Antwerp, Belgium.
| | - Hilde Bastiaens
- Department of family medicine and population health, Antwerp University, Antwerp, Belgium
| | - Sibyl Anthierens
- Department of family medicine and population health, Antwerp University, Antwerp, Belgium
| | - Fekadu Massebo
- Department of Biology, College of Natural Sciences, Arba Minch University, Arba Minch, Ethiopia
| | - Matewos Masne
- Department of Biology, College of Natural Sciences, Arba Minch University, Arba Minch, Ethiopia
| | - Gelila Biresaw
- Department of Medical Laboratory Science, College of Medicine and Health Sciences, Arba Minch University, Arba Minch, Ethiopia
| | - Misgun Shewangizaw
- Department of Public Health, College of Medicine and Health Sciences, Arba Minch University, Arba Minch, Ethiopia
| | - Abayneh Tunje
- Department of Public Health, College of Medicine and Health Sciences, Arba Minch University, Arba Minch, Ethiopia
| | - Yilma Chisha
- Department of Public Health, College of Medicine and Health Sciences, Arba Minch University, Arba Minch, Ethiopia
| | - Tsegaye Yohannes
- Department of Medical Laboratory Science, College of Medicine and Health Sciences, Arba Minch University, Arba Minch, Ethiopia
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Hardy H, Harte SJ, Hopkins RJ, Mnyone L, Hawkes FM. The influence of manure-based organic fertilisers on the oviposition behaviour of Anopheles arabiensis. Acta Trop 2023:106954. [PMID: 37244404 DOI: 10.1016/j.actatropica.2023.106954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 05/23/2023] [Accepted: 05/24/2023] [Indexed: 05/29/2023]
Abstract
The rice agroecosystem provides suitable breeding habitat for many malaria vector species, and rice-adjacent communities are consequently exposed to a greater malaria transmission risk than non-rice-associated communities. As part of efforts to expand rice production in Africa, sustainable and climate-adapted practices such as the System of Rice Intensification (SRI) are being promoted. SRI encourages the use of organic fertilisers (OFs) such as cow and chicken dung, as opposed to inorganic industrially produced fertilisers, due to their lower resource cost, apparent benefit to the rice agroecosystem and as a means to reduce the greenhouse gas emissions associated with the production of industrial fertilisers. However, the impact of OFs on mosquito fauna is not well documented and may have knock-on consequences on malaria transmission risk. Here, we demonstrate, using dual choice egg count assays, that both cow and chicken dung modulate the oviposition behaviour of Anopheles arabiensis, a major malaria vector in Sub-Saharan Africa. A significantly reduced proportion of eggs were laid in water treated with either cow or chicken dung compared to untreated water, with higher dung concentrations resulting in further reduced proportions. When presented in competition, significantly fewer eggs were laid in water treated with chicken dung than with cow dung. Moreover, there was no evidence of egg retention in any experiment, including in no-choice experiments where only dung-containing dishes were available. These results suggest both cow and chicken dung may act as oviposition deterrents to malaria vector species and that the application of manure-based OFs in rice agriculture may modulate the oviposition behaviour of An. gambiae s.l. within agroecosystems. Quantification of the ammonia present in dung-infused water showed higher concentrations were present in the chicken dung infusion, which may be one contributing factor to the difference in observed deterrence between the two dung types. Deterrence of mosquito oviposition in OF-treated farms may potentially affect the overall production of malaria vectors within rice fields and their contribution to local malaria transmission.
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Affiliation(s)
- Harrison Hardy
- Natural Resources Institute, University of Greenwich, UK..
| | - Steven J Harte
- Natural Resources Institute, University of Greenwich, UK..
| | | | - Ladslaus Mnyone
- Institute of Pest Management, Sokoine University of Agriculture, Tanzania.; Department of Science, Technology and Innovation, Ministry of Education, Science and Technology, Tanzania..
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Acford-Palmer H, Phelan JE, Tadesse FG, Kristan M, Collins E, Spadar A, Walker T, Bousema T, Messenger LA, Clark TG, Campino S. Identification of two insecticide resistance markers in Ethiopian Anopheles stephensi mosquitoes using a multiplex amplicon sequencing assay. Sci Rep 2023; 13:5612. [PMID: 37019918 PMCID: PMC10076309 DOI: 10.1038/s41598-023-32336-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 03/26/2023] [Indexed: 04/07/2023] Open
Abstract
Since its first detection in 2012 in Djibouti, Anopheles stephensi has invaded and established in the Horn of Africa, and more recently Nigeria. The expansion of this vector poses a significant threat to malaria control and elimination efforts. Integrated vector management is the primary strategy used to interrupt disease transmission; however, growing insecticide resistance is threatening to reverse gains in global malaria control. We present a next-generation amplicon-sequencing approach, for high-throughput monitoring of insecticide resistance genes (ace1, GSTe2, vgsc and rdl), species identification and characterization of genetic diversity (its2 and cox1) in An. stephensi. Ninety-five An. stephensi mosquitoes, collected in Ethiopia, were screened, identifying 104 SNPs, including the knock-down mutation L958F (L1014F in Musca domestica), and for the first time in this vector species, the A296S substitution (A301S in Drosophila melanogaster) in the rdl locus. Two other amino acid substitutions (ace1-N177D, GSTe2-V189L) were also identified but have not been previously implicated in insecticide resistance. Genetic diversity in the mitochondrial cox1 gene revealed shared haplotypes between Ethiopian An. stephensi with samples from Pakistan, Sudan, and Djibouti. Overall, we present a reliable, cost-effective strategy using amplicon-sequencing to monitor known insecticide resistance mutations, with the potential to identify new genetic variants, to assist in the high-throughput surveillance of insecticide resistance in An. stephensi populations.
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Affiliation(s)
- Holly Acford-Palmer
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Jody E Phelan
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Fitsum G Tadesse
- Malaria and NTD Directorate, Armauer Hansen Research Institute, ALERT Hospital Compound, P.O. Box 1005, Addis Ababa, Ethiopia
| | - Mojca Kristan
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Emma Collins
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Anton Spadar
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Thomas Walker
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Louisa A Messenger
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
- Environmental and Occupational Health, School of Public Health, University of Nevada, Las Vegas, Las Vegas, USA
| | - Taane G Clark
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
- Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK
| | - Susana Campino
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.
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Althoff RA, Huijben S. Comparison of the variability in mortality data generated by CDC bottle bioassay, WHO tube test, and topical application bioassay using Aedes aegypti mosquitoes. Parasit Vectors 2022; 15:476. [PMID: 36539831 PMCID: PMC9769033 DOI: 10.1186/s13071-022-05583-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 11/08/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Insecticide resistance remains a major public health problem. Resistance surveillance is critical for effective vector control and resistance management planning. Commonly used insecticide susceptibility bioassays for mosquitoes are the CDC bottle bioassay and the WHO tube test. Less commonly used in the field but considered the gold standard for assessing insecticide susceptibility in the development of novel insecticides is the topical application bioassay. Each of these bioassays has critical differences in how they assess insecticide susceptibility that impacts their ability to differentiate between resistant and susceptible populations or determine different levels of resistance intensity. METHODS We compared the CDC bottle bioassay, the WHO tube test, and the topical application bioassay in establishing the dose-response against deltamethrin (DM) using the DM-resistant Aedes aegypti strain MC1. Mosquitoes were exposed to a range of insecticide concentrations to establish a dose-response curve and assess variation around model predictions. In addition, 10 replicates of 20-25 mosquitoes were exposed to a fixed dose with intermediate mortality to assess the degree of variation in mortality. RESULTS The topical application bioassay exhibited the lowest amount of variation in the dose-response data, followed by the WHO tube test. The CDC bottle bioassay had the highest level of variation. In the fixed-dose experiment, a higher variance was similarly found for the CDC bottle bioassay compared with the WHO tube test and topical application bioassay. CONCLUSION These data suggest that the CDC bottle bioassay has the lowest power and the topical application bioassay the highest power to differentiate between resistant and susceptible populations and assess changes over time and between populations. This observation has significant implications for the interpretation of surveillance results from different assays. Ultimately, it will be important to discuss optimal insecticide resistance surveillance tools in terms of the surveillance objective, practicality in the field, and accuracy of the tool to reach that objective.
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Affiliation(s)
- Rachel A. Althoff
- grid.215654.10000 0001 2151 2636The Center for Evolution & Medicine, School of Life Sciences, Arizona State University, Tempe, AZ USA
| | - Silvie Huijben
- grid.215654.10000 0001 2151 2636The Center for Evolution & Medicine, School of Life Sciences, Arizona State University, Tempe, AZ USA ,grid.215654.10000 0001 2151 2636Computational and Modeling Sciences Center, Simon A. Levin Mathematical, Arizona State University, Tempe, AZ USA
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Yewhalaw D, Simma EA, Zemene E, Zeleke K, Degefa T. Residual efficacy of SumiShield™ 50WG for indoor residual spraying in Ethiopia. Malar J 2022; 21:364. [PMID: 36461066 PMCID: PMC9716761 DOI: 10.1186/s12936-022-04395-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 11/19/2022] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND The rate of decay of the biological efficacy of insecticides used for indoor residual spraying (IRS) is an important factor when making decisions on insecticide choice for national malaria control programmes. A key roadblock to IRS programme is insecticide resistance. If resistance is detected to most of the existing insecticides used for IRS (DDT, pyrethroids, organophosphates and carbamates), the logical next choice could be neonicotinoid insecticides, as pyrethroids are used to treat nets. SumiShield™ 50WG belongs to the neonicotinoid class of insecticides and has shown promising results in several phase I, II and III trials in different settings. The aim of this study was to assess the persistence of SumiShield™ 50WG by spraying on different wall surfaces and determine its decay rates over time in Ethiopia. METHODS Five huts with different wall surface types (mud, dung, paint and cement) which represented the Ethiopian house wall surfaces were used to evaluate the residual efficacy of SumiShield™ 50WG. Actellic 300CS sprayed on similar wall surfaces of another five huts was used as a comparator insecticide and two huts sprayed with water were used as a control. All huts were sprayed uniformly by an experienced spray operator; non-stop starting from the door and moving clockwise to cover the entire wall surface of the hut. The treatments were assigned to huts randomly. The residual efficacy of the insecticide formulations was evaluated against a susceptible insectary-reared population of Anopheles arabiensis using WHO cone bioassays. RESULTS SumiShield™ 50WG resulted in mortality rates of over 80% at 120 h post-exposure on all surface types for up to nine months post-spray, while Actellic 300CS yielded mortality rates of over 80% for eight months after spray. CONCLUSIONS The results of this trial demonstrated that the residual efficacy of SumiShield™ 50WG extends up to nine months on all treated wall surface types. The long-lasting residual efficacy and unique mode of action of the SemiShield™ 50WG shows that it could be an ideal product to be considered as a potential candidate insecticide formulation for IRS in malaria endemic countries such as Ethiopia or other sub-Saharan countries where the transmission season lasts up to four months or longer.
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Affiliation(s)
- Delenasaw Yewhalaw
- grid.411903.e0000 0001 2034 9160School of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia ,grid.411903.e0000 0001 2034 9160Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
| | - Eba Alemayehu Simma
- grid.411903.e0000 0001 2034 9160Departement of Biology, College of Natural Sciences, Jimma University, Jimma, Ethiopia
| | - Endalew Zemene
- grid.411903.e0000 0001 2034 9160School of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia
| | - Kassahun Zeleke
- grid.411903.e0000 0001 2034 9160Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
| | - Teshome Degefa
- grid.411903.e0000 0001 2034 9160School of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia
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11
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Githure JI, Yewhalaw D, Atieli H, Hemming-Schroeder E, Lee MC, Wang X, Zhou G, Zhong D, King CL, Dent A, Mukabana WR, Degefa T, Hsu K, Githeko AK, Okomo G, Dayo L, Tushune K, Omondi CO, Taffese HS, Kazura JW, Yan G. Enhancing Malaria Research, Surveillance, and Control in Endemic Areas of Kenya and Ethiopia. Am J Trop Med Hyg 2022; 107:14-20. [PMID: 36228905 PMCID: PMC9662210 DOI: 10.4269/ajtmh.21-1303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 07/18/2022] [Indexed: 01/27/2023] Open
Abstract
Malaria control programs in Africa encounter daunting challenges that hinder progressive steps toward elimination of the disease. These challenges include widespread insecticide resistance in mosquito vectors, increasing outdoor malaria transmission, lack of vector surveillance and control tools suitable for outdoor biting vectors, weakness in malaria surveillance, and an inadequate number of skilled healthcare personnel. Ecological and epidemiological changes induced by environmental modifications resulting from water resource development projects pose additional barriers to malaria control. Cognizant of these challenges, our International Center of Excellence for Malaria Research (ICEMR) works in close collaboration with relevant government ministries and agencies to align its research efforts with the objectives and strategies of the national malaria control and elimination programs for the benefit of local communities. Our overall goal is to assess the impact of water resource development projects, shifting agricultural practices, and vector interventions on Plasmodium falciparum and P. vivax malaria in Kenya and Ethiopia. From 2017 to date, the ICEMR has advanced knowledge of malaria epidemiology, transmission, immunology, and pathogenesis, and developed tools to enhance vector surveillance and control, improved clinical malaria surveillance and diagnostic methods, and strengthened the capacity of local healthcare providers. Research findings from the ICEMR will inform health policy and strategic planning by ministries of health in their quest to sustain malaria control and achieve elimination goals.
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Affiliation(s)
| | - Delenasaw Yewhalaw
- Department of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia;,Tropical and Infectious Diseases Research Center, Jimma University, Jimma, Ethiopia
| | - Harrysone Atieli
- School of Public Health and Community Development, Maseno University, Kisumu, Kenya
| | | | - Ming-Chieh Lee
- Program in Public Health, University of California at Irvine, Irvine, California
| | - Xiaoming Wang
- Program in Public Health, University of California at Irvine, Irvine, California
| | - Guofa Zhou
- Program in Public Health, University of California at Irvine, Irvine, California
| | - Daibin Zhong
- Program in Public Health, University of California at Irvine, Irvine, California
| | - Christopher L. King
- Center for Global Health & Diseases, Case Western Reserve University, Cleveland, Ohio
| | - Arlene Dent
- Center for Global Health & Diseases, Case Western Reserve University, Cleveland, Ohio
| | | | - Teshome Degefa
- Department of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia
| | - Kuolin Hsu
- Center for Hydrometeorology and Remote Sensing, Department of Civil and Environmental Engineering, University of California at Irvine, Irvine, California
| | - Andrew K. Githeko
- Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Gordon Okomo
- Ministry of Health, Homa Bay County, Homa Bay, Kenya
| | - Lilyana Dayo
- Ministry of Health, Kisumu County, Kisumu, Kenya
| | - Kora Tushune
- Department of Health Management and Policy, Faculty of Public Health, Jimma University, Jimma, Ethiopia
| | | | - Hiwot S. Taffese
- National Malaria Program, Federal Ministry of Health, Addis Ababa, Ethiopia
| | - James W. Kazura
- Center for Global Health & Diseases, Case Western Reserve University, Cleveland, Ohio;,Address correspondence to Guiyun Yan, Program in Public Health, University of California at Irvine, Irvine, CA, E-mail: or James Kazura, Center for Global Health & Diseases, Case Western Reserve University, Cleveland, OH, E-mail:
| | - Guiyun Yan
- Program in Public Health, University of California at Irvine, Irvine, California;,Address correspondence to Guiyun Yan, Program in Public Health, University of California at Irvine, Irvine, CA, E-mail: or James Kazura, Center for Global Health & Diseases, Case Western Reserve University, Cleveland, OH, E-mail:
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12
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Yewhalaw D, Balkew M, Zemene E, Chibsa S, Mumba P, Flatley C, Seyoum A, Yoshimizu M, Zohdy S, Dengela D, Irish S. An experimental hut study evaluating the impact of pyrethroid-only and PBO nets alone and in combination with pirimiphos-methyl-based IRS in Ethiopia. Malar J 2022; 21:238. [PMID: 35987650 PMCID: PMC9392245 DOI: 10.1186/s12936-022-04263-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 08/10/2022] [Indexed: 11/10/2022] Open
Abstract
Background Pyrethroid resistance observed in populations of malaria vectors is widespread in Ethiopia and could potentially compromise the effectiveness of insecticide-based malaria vector control interventions. In this study, the impact of combining indoor residual spraying (IRS) and insecticide-treated nets (ITNs) on mosquito behaviour and mortality was evaluated using experimental huts. Methods A Latin Square Design was employed using six experimental huts to collect entomological data. Human volunteers slept in huts with different types of nets (pyrethroid-only net, PBO net, and untreated net) either with or without IRS (Actellic 300CS). The hut with no IRS and an untreated net served as a negative control. The study was conducted for a total of 54 nights. Both alive and dead mosquitoes were collected from inside nets, in the central rooms and verandah the following morning. Data were analysed using Stata/SE 14.0 software package (College Station, TX, USA). Results The personal protection rate of huts with PermaNet® 2.0 alone and PermaNet® 3.0 alone was 33.3% and 50%, respectively. The mean killing effect of huts with PermaNet® 2.0 alone and PermaNet® 3.0 alone was 2% and 49%, respectively. Huts with PermaNet® 2.0 alone and PermaNet® 3.0 alone demonstrated significantly higher excito-repellency than the control hut. However, mosquito mortality in the hut with IRS + untreated net, hut with IRS + PermaNet® 2.0 and hut with IRS + PermaNet® 3.0 were not significantly different from each other (p > 0.05). Additionally, pre-exposure of both the susceptible Anopheles arabiensis laboratory strain and wild Anopheles gambiae sensu lato to PBO in the cone bioassay tests of Actellic 300CS sprayed surfaces did not reduce mosquito mortality when compared to mortality without pre-exposure to PBO. Conclusion Mosquito mortality rates from the huts with IRS alone were similar to mosquito mortality rates from the huts with the combination of vector control intervention tools (IRS + ITNs) and mosquito mortality rates from huts with PBO nets alone were significantly higher than huts with pyrethroid-only nets. The findings of this study help inform studies to be conducted under field condition for decision-making for future selection of cost-effective vector control intervention tools. Graphical Abstract ![]()
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Chan K, Cano J, Massebo F, Messenger LA. Cattle-related risk factors for malaria in southwest Ethiopia: a cross-sectional study. Malar J 2022; 21:179. [PMID: 35689237 PMCID: PMC9188194 DOI: 10.1186/s12936-022-04202-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 05/19/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Despite the low to moderate intensity of malaria transmission present in Ethiopia, malaria is still a leading public health problem. Current vector control interventions, principally long-lasting insecticidal nets and indoor residual spraying, when deployed alone or in combination, are insufficient to control the dominant vector species due to their exophagic and exophilic tendencies. Zooprophylaxis presents a potential supplementary vector control method for malaria; however, supporting evidence for its efficacy has been mixed. METHODS To identify risk factors of malaria and to estimate the association between cattle and Anopheles vector abundance as well as malaria risk, a cross-sectional study was conducted in a village near Arba Minch, Ethiopia. Epidemiological surveys (households = 95, individuals = 463), mosquito collections using CDC light traps and a census of cattle and human populations were conducted. To capture environmental conditions, land cover and water bodies were mapped using satellite imagery. Risk factor analyses were performed through logistic, Poisson, negative binomial, and spatial weighted regression models. RESULTS The only risk factor associated with self-reported malaria illness at an individual level was being a child aged 5 or under, where they had three times higher odds than adults. At the household level, variables associated with malaria vector abundance, especially those indoors, included socioeconomic status, the proportion of children in a household and cattle population density. CONCLUSIONS Study results are limited by the low abundance of malaria vectors found and use of self-reported malaria incidence. Environmental factors together with a household's socioeconomic status and host availability played important roles in the risk of malaria infection in southwest Ethiopia. Cattle abundance in the form of higher cattle to human ratios may act as a protective factor against mosquito infestation and malaria risk. Humans should remain indoors to maximize potential protection against vectors and cattle kept outside of homes.
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Affiliation(s)
- Kallista Chan
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
| | - Jorge Cano
- Expanded Special Project for Elimination of NTDs, World Health Organization Regional Office for Africa, Brazzaville, Republic of Congo
| | - Fekadu Massebo
- Department of Biology, Collage of Natural Sciences, Arba Minch University, Arba Minch, Ethiopia
| | - Louisa A Messenger
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK.
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Chanyalew T, Natea G, Amenu D, Yewhalaw D, Simma EA. Composition of mosquito fauna and insecticide resistance status of Anopheles gambiae sensu lato in Itang special district, Gambella, Southwestern Ethiopia. Malar J 2022; 21:125. [PMID: 35436961 PMCID: PMC9014582 DOI: 10.1186/s12936-022-04150-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 04/04/2022] [Indexed: 11/10/2022] Open
Abstract
Background Anopheles arabiensis, member species of the Anopheles gambiae complex, is the primary vector of malaria and is widely distributed in Ethiopia. Anopheles funestus, Anopheles pharoensis and Anopheles nili are secondary vectors occurring with limited distribution in the country. Indoor residual spraying (IRS) and long-lasting insecticidal nets (LLINs) are pillars for the interventions against malaria control and elimination efforts in Ethiopia. However, the emergence and widespread of insecticide resistance in An. gambiae sensu lato (s.l.), might compromise the control efforts of the country. The aim of this study was to investigate composition of mosquito fauna and insecticide resistance status of An. gambiae s.l. in Itang special district ( woreda), Gambella, southwestern Ethiopia. Methods Adult mosquitoes were sampled from September 2020 to February 2021 using the CDC light trap and pyrethrum spray catch (PSC). CDC light traps were placed in three selected houses for two consecutive days per month to collect mosquitoes indoor and outdoor from 6:00 P.M. to 06:00 A.M. and PSC was used to collect indoor resting mosquitoes from ten selected houses once in a month from October 2020 to February 2021. Moreover, mosquito larvae were also collected from different breeding sites and reared to adults to assess susceptibility status of populations of An. gambiae s.l. in the study area. Susceptibility tests were conducted on two to three days old non blood fed female An. gambiae s.l. using insecticide impregnated papers with deltamethrin (0.05%), alpha-cypermethrin (0.05%), propoxur (0.1%), pirimiphos-methyl (0.25%) and bendiocarb (0.1%) following World Health Organization (WHO) standard susceptibility test procedure. Molecular diagnostics were done for the identification of member species of An. gambiae s.l. and detection of knockdown resistance (kdr) allele using species specific polymerase chain reaction (PCR) and allele specific PCR. Results In total, 468 adult mosquitoes were collected from different houses. Culex mosquitoes were the most dominant (80.4%) followed by Anopheles mosquitoes. Three species of Anopheles (Anopheles coustani, An. pharoensis, and An. gambiae s.l.) were identified, of which An. coustani was the dominant (8.1%) species. Higher number of mosquitoes (231) were collected outdoor by CDC light traps. Out of 468 adult mosquitoes, 294 were blood fed, 46 were half-gravid and gravid whereas the remaining 128 were unfed. WHO bioassay tests revealed that the populations of An. gambiae s.l. in the study area are resistant against alpha-cypermethrin and deltamethrin, but susceptible to bendiocarb, pirimiphos-methyl and propoxur. Of the total 86 An. gambiae s.l. specimens assayed, 79 (92%) successfully amplified and identified as An. arabiensis. West African kdr (L1014F) mutation was detected with high kdr allele frequency ranging from 67 to 88%. Conclusion The detection of target site mutation, kdr L1014F allele, coupled with the phenotypic resistance against alpha-cypermethrin and deltamethrin call for continuous resistance monitoring.
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Demissew A, Animut A, Kibret S, Tsegaye A, Hawaria D, Degefa T, Getachew H, Lee MC, Yan G, Yewhalaw D. Evidence of pyrethroid resistance in Anopheles amharicus and Anopheles arabiensis from Arjo-Didessa irrigation scheme, Ethiopia. PLoS One 2022; 17:e0261713. [PMID: 35030201 PMCID: PMC8759678 DOI: 10.1371/journal.pone.0261713] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 12/08/2021] [Indexed: 11/18/2022] Open
Abstract
Background Indoor residual spraying and insecticide-treated nets are among the key malaria control intervention tools. However, their efficacy is declining due to the development and spread of insecticide resistant vectors. In Ethiopia, several studies reported resistance of An. arabiensis to multiple insecticide classes. However, such data is scarce in irrigated areas of the country where insecticides, pesticides and herbicides are intensively used. Susceptibility of An. gambiae s.l. to existing and new insecticides and resistance mechanisms were assessed in Arjo-Didessa sugarcane plantation area, southwestern Ethiopia. Methods Adult An. gambiae s.l. reared from larval/pupal collections of Arjo-Didessa sugarcane irrigation area and its surrounding were tested for their susceptibility to selected insecticides. Randomly selected An. gambiae s.l. (dead and survived) samples were identified to species using species-specific polymerase chain reaction (PCR) and were further analyzed for the presence of knockdown resistance (kdr) alleles using allele-specific PCR. Results Among the 214 An. gambiae s.l. samples analyzed by PCR, 89% (n = 190) were An. amharicus and 9% (n = 20) were An. arabiensis. Mortality rates of the An. gambiae s.l. exposed to deltamethrin and alphacypermethrin were 85% and 86.8%, respectively. On the other hand, mortalities against pirmiphos-methyl, bendiocarb, propoxur and clothianidin were 100%, 99%, 100% and 100%, respectively. Of those sub-samples (An. amharicus and An. arabiensis) examined for presence of kdr gene, none of them were found to carry the L1014F (West African) allelic mutation. Conclusion Anopheles amharicus and An. arabiensis from Arjo-Didessa sugarcane irrigation area were resistant to pyrethroids which might be synergized by extensive use of agricultural chemicals. Occurrence of pyrethroid resistant malaria vectors could challenge the ongoing malaria control and elimination program in the area unless resistance management strategies are implemented. Given the resistance of An. amharicus to pyrethroids, its behavior and vectorial capacity should be further investigated.
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Affiliation(s)
- Assalif Demissew
- Department of Medical Laboratory Sciences, College of Medicine and Health Sciences, Ambo University, Ambo, Ethiopia
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
- * E-mail: ,
| | - Abebe Animut
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
| | - Solomon Kibret
- Program in Public Health, University of California at Irvine, Irvine, California, United States of America
| | - Arega Tsegaye
- Department of Biology, College of Natural Science, Jimma University, Jimma, Ethiopia
- Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
| | - Dawit Hawaria
- Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
- Yirgalem Hospital Medical College, Yirgalem, Ethiopia
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia
| | - Teshome Degefa
- Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia
| | - Hallelujah Getachew
- Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia
- Department of Medical Laboratory Sciences, Arbaminch College of Health Sciences, Arba Minch, Ethiopia
| | - Ming-Chieh Lee
- Program in Public Health, University of California at Irvine, Irvine, California, United States of America
| | - Guiyun Yan
- Program in Public Health, University of California at Irvine, Irvine, California, United States of America
| | - Delenasaw Yewhalaw
- Tropical and Infectious Diseases Research Center (TIDRC), Jimma University, Jimma, Ethiopia
- School of Medical Laboratory Sciences, Faculty of Health Sciences, Jimma University, Jimma, Ethiopia
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Animut A, Horstmann S. Residual efficacy of Fludora Fusion against Anopheles arabiensis in simple huts in Ethiopia. PLoS One 2022; 17:e0263840. [PMID: 35148353 PMCID: PMC8836335 DOI: 10.1371/journal.pone.0263840] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Accepted: 01/27/2022] [Indexed: 11/18/2022] Open
Abstract
Emergence and spread of malaria vectors resistant to the available insecticides required a new and efficacious insecticide. Residual efficacy of Fludora® Fusion was evaluated against insecticide susceptible Anopheles arabiensis in ten circular huts similar to the residential huts. Fludora® Fusion WP-SB 56.25, FICAM WP80 and Clothianidin WG70 were sprayed, by experienced technician, on interior wall surfaces: paint, dung, smooth mud, and rough mud. WHO cone bioassays were carried out a month after spraying and thereafter on monthly intervals for 12 months. Knockdown was recorded at 60 minutes and mortality at 24 hours, 48 hours and 72 hours holding time post-exposure. Fludora Fusion induced 100% An. arabiensis mortality during the first four months post-treated on all surface types at 24 hours holding time post-exposure. Its activity remained over 80% from the fifth to the twelfth month post-treated on the surfaces with the exception of two assessment points, at seventh month and eleventh month, on paint and smooth mud surfaces. FICAM induced 100% mortality rate during the first 4 months and 92% mortality during the fifth month post-treatment on painted surfaces. Its activity was over 96% mortality 1-month post-treatment on smooth mud and rough mud surfaces and 92% mortality 2-month post-treatment on dung surfaces. Clothianidin caused 89% and 86% mortality 1-month post-treatment on smooth mud and rough mud surfaces. Fludora Fusion can be used as alternative indoor residual insecticide spraying against An. arabiensis in Ethiopia.
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Affiliation(s)
- Abebe Animut
- Medical Entomology, Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
- * E-mail: ,
| | - Sebastian Horstmann
- Research & Development, Bayer AG Crop Science, Laboratory Vector Control, Field Testing, Monheim, Germany
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Asale A, Abro Z, Enchalew B, Teshager A, Belay A, Kassie M, Mutero CM. Community knowledge, perceptions, and practices regarding malaria and its control in Jabi Tehnan district, Amhara Region, Northwest Ethiopia. Malar J 2021; 20:459. [PMID: 34886848 PMCID: PMC8656029 DOI: 10.1186/s12936-021-03996-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 11/28/2021] [Indexed: 11/20/2022] Open
Abstract
Background Use of long-lasting insecticidal nets (LLINs), indoor residual spraying (IRS), community-based malaria education, prompt diagnosis and treatment are key programme components of malaria prevention and control in Ethiopia. However, the effectiveness of these interventions is often undermined by various challenges, including insecticide and drug resistance, the plasticity of malaria vectors feeding and biting behaviour, and certain household factors that lead to misuse and poor utilization of LLINs. The primary objective of this study was to document households’ perceptions towards malaria and assess the prevalence of the disease and the constraints related to the ongoing interventions in Ethiopia (LLINs, IRS, community mobilization house screening). Methods The study was conducted in Jabi Tehnan district, Northwestern Ethiopia, from November 2019 to March 2020. A total of 3010 households from 38 villages were randomly selected for socio-economic and demographic survey. Focus group discussions (FGDs) were conducted in 11 different health clusters considering agro-ecological differences. A total of 1256 children under 10 years of age were screened for malaria parasites using microscopy to determine malaria prevalence. Furthermore, 5-year malaria trend analysis was undertaken based on data obtained from the district health office to understand the disease dynamics. Results Malaria knowledge in the area was high as all FGD participants correctly identified mosquito bites during the night as sources of malaria transmission. Delayed health-seeking behaviour remains a key behavioural challenge in malaria control as it took patients on average 4 days before reporting the case at the nearby health facility. On average, households lost 2.53 working days per person-per malaria episode and they spent US$ 18 per person per episode. Out of the 1256 randomly selected under 10 children tested for malaria parasites, 11 (0.89%) were found to be positive. Malaria disproportionately affected the adult segment of the population more, with 50% of the total cases reported from households being from among individuals who were 15 years or older. The second most affected group was the age group between 5 and 14 years followed by children aged under 5, with 31% and 14% burden, respectively. Conclusion Despite the achievement of universal coverage in terms of LLINs access, utilization of vector control interventions in the area remained low. Using bed nets for unintended purposes remained a major challenge. Therefore, continued community education and communication work should be prioritized in the study area to bring about the desired behavioural changes. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-021-03996-5.
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Affiliation(s)
- Abebe Asale
- International Center of Insect Physiology and Ecology, Addis Ababa, Ethiopia.
| | - Zewdu Abro
- International Center of Insect Physiology and Ecology, Addis Ababa, Ethiopia
| | - Bayu Enchalew
- International Center of Insect Physiology and Ecology, Addis Ababa, Ethiopia
| | - Alayu Teshager
- International Center of Insect Physiology and Ecology, Addis Ababa, Ethiopia
| | - Aklilu Belay
- International Center of Insect Physiology and Ecology, Nairobi, Kenya.,University of Pretoria Institute for Sustainable Malaria Control, School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa
| | - Menale Kassie
- International Center of Insect Physiology and Ecology, Nairobi, Kenya
| | - Clifford Maina Mutero
- International Center of Insect Physiology and Ecology, Nairobi, Kenya.,University of Pretoria Institute for Sustainable Malaria Control, School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa
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Messenger LA, Impoinvil LM, Derilus D, Yewhalaw D, Irish S, Lenhart A. A whole transcriptomic approach provides novel insights into the molecular basis of organophosphate and pyrethroid resistance in Anopheles arabiensis from Ethiopia. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2021; 139:103655. [PMID: 34562591 DOI: 10.1016/j.ibmb.2021.103655] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 09/15/2021] [Accepted: 09/20/2021] [Indexed: 06/13/2023]
Abstract
The development of insecticide resistance in malaria vectors is of increasing concern in Ethiopia because of its potential implications for vector control failure. To better elucidate the specificity of resistance mechanisms and to facilitate the design of control strategies that minimize the likelihood of selecting for cross-resistance, a whole transcriptomic approach was used to explore gene expression patterns in a multi-insecticide resistant population of Anopheles arabiensis from Oromia Region, Ethiopia. This field population was resistant to the diagnostic doses of malathion (average mortality of 71.9%) and permethrin (77.4%), with pools of survivors and unexposed individuals analyzed using Illumina RNA-sequencing, alongside insecticide susceptible reference strains. This population also demonstrated deltamethrin resistance but complete susceptibility to alpha-cypermethrin, bendiocarb and propoxur, providing a phenotypic basis for detecting insecticide-specific resistance mechanisms. Transcriptomic data revealed overexpression of genes including cytochrome P450s, glutathione-s-transferases and carboxylesterases (including CYP4C36, CYP6AA1, CYP6M2, CYP6M3, CYP6P4, CYP9K1, CYP9L1, GSTD3, GSTE2, GSTE3, GSTE4, GSTE5, GSTE7 and two carboxylesterases) that were shared between malathion and permethrin survivors. We also identified nineteen highly overexpressed cuticular-associated proteins (including CYP4G16, CYP4G17 and chitinase) and eighteen salivary gland proteins (including D7r4 short form salivary protein), which may be contributing to a non-specific resistance phenotype by either enhancing the cuticular barrier or promoting binding and sequestration of insecticides, respectively. These findings provide novel insights into the molecular basis of insecticide resistance in this lesser well-characterized major malaria vector species.
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Affiliation(s)
- Louisa A Messenger
- Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, U.S. Centers for Disease Control and Prevention, 1600 Clifton Rd. Atlanta, GA, 30329, USA; American Society for Microbiology, 1752 N Street, NW Washington, DC, 20036, USA; Department of Disease Control, Faculty of Infectious Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, United Kingdom
| | - Lucy Mackenzie Impoinvil
- Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, U.S. Centers for Disease Control and Prevention, 1600 Clifton Rd. Atlanta, GA, 30329, USA
| | - Dieunel Derilus
- Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, U.S. Centers for Disease Control and Prevention, 1600 Clifton Rd. Atlanta, GA, 30329, USA
| | - Delenasaw Yewhalaw
- Tropical and Infectious Diseases Research Center, Jimma University, Jimma, Ethiopia; Department of Medical Laboratory Sciences and Pathology, College of Health Sciences, Jimma University, Jimma, Ethiopia
| | - Seth Irish
- Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, U.S. Centers for Disease Control and Prevention, 1600 Clifton Rd. Atlanta, GA, 30329, USA; President's Malaria Initiative, Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, U.S. Centers for Disease Control and Prevention, 1600 Clifton Rd. Atlanta, GA, 30329, USA
| | - Audrey Lenhart
- Entomology Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, U.S. Centers for Disease Control and Prevention, 1600 Clifton Rd. Atlanta, GA, 30329, USA.
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Mekonen S, Ambelu A, Wondafrash M, Kolsteren P, Spanoghe P. Exposure of infants to organochlorine pesticides from breast milk consumption in southwestern Ethiopia. Sci Rep 2021; 11:22053. [PMID: 34764390 PMCID: PMC8585979 DOI: 10.1038/s41598-021-01656-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 10/25/2021] [Indexed: 11/12/2022] Open
Abstract
Breast milk is often used as an environmental bioindicator since it serves as an important medium to accumulate organochlorine pesticides. The main aim of this study is to determine the level of organochlorine pesticides in human breast milk collected from three districts of southwestern Ethiopia (Asendabo, Deneba, and Serbo) at three times points baselines (1st month), midline ( six months), and end line (12 months) and risk of infants’ exposure. A longitudinal study was conducted to assess pesticide residues in human breast milk samples and evaluate the risk-exposure of infants to these pesticides from consumption of mother’s milk in Ethiopia. Breast milk samples were collected from 168 mothers at three time points and pesticides were extracted using the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method. The level of pesticide residues in human milk samples and exposure of infants to the pesticides was evaluated by calculating the estimated daily intake and compared with the provisional tolerable daily intake of the pesticides under study. The results indicated that, from the eight organochlorine pesticides analyzed in 447 breast milk samples at three sampling times, DDT and its metabolites were detected. p,p′-DDE and p,p′-DDT were detected in all (100%) of the breast milk samples while, p,p-DDD, and o,p-DDT were detected in 53.9%, and 42.7%, respectively. The mean concentration of total DDT at three time points(baseline, midline and endline) were 2.25, 1.68 and 1.32 µg/g milk fat, respectively. The mean concentration of total DDT from the three districts was 1.85 µg/g milk fat which is above the maximum residue limit (MRL = 0.02 µg/g milk fat set by FAO/WHO). The mean ratio of DDT/DDE for the three areas was calculated less than five (< 5) indicates historical DDT use in the study area. The estimated daily intake of infants at the first month of breastfeeding was 11.24 µg/kg-BW/day, above the provisional tolerable daily intake (PTDI) for total DDT set by FAO/WHO, which is 10 µg/kg body weight. An intake of OCPs is a big concern for infants' health in Ethiopia and countries with a similar condition, particularly at the first month of lactation. Strict regulations of the health-threatening pesticide by the regulatory body (Environment, Forest and Climate Change Commission) at the country and regional levels is advocated.
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Affiliation(s)
- Seblework Mekonen
- Department of Environmental Health Sciences and Technology, Jimma University, P.O. Box 378, Jimma, Ethiopia
| | - Argaw Ambelu
- Department of Environmental Health Sciences and Technology, Jimma University, P.O. Box 378, Jimma, Ethiopia.
| | | | - Patrick Kolsteren
- Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University Coupure Links 653, 9000, Ghent, Belgium
| | - Pieter Spanoghe
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
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Dugassa S, Mekonnen S, Muthee PW, Peter R, Zinyengere D, Feyasa MB, Sievert K. Evaluation of the Residual Efficacy of Actellic300 CS in Simple Huts in Central Ethiopia. JOURNAL OF MEDICAL ENTOMOLOGY 2021; 58:2308-2313. [PMID: 34104949 DOI: 10.1093/jme/tjab096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Indexed: 06/12/2023]
Abstract
Indoor residual spraying (IRS) is one of the key vector control tools with a long history of use in the world. Ethiopia has set a goal to eliminate malaria from selected districts mainly by applying IRS and the distribution of long-lasting insecticidal nets. IRS is applied in low malaria transmission districts which are epidemic prone and in districts with high malaria transmission. Ethiopia uses insecticides that are recommended by World Health Organization; these insecticides must also be registered in Ethiopia. The registration of new and potential products requires confirmatory, local efficacy trials to be performed. Actellic 300CS, now registered, is one of such potential product. Actellic 300CS showed average mortalities of 99.6%, 99.6%, and 99.0% on the sprayed surfaces in the experimental huts, the top, middle, and bottom sections, respectively during the first 6 mo of the study period. Beyond 6 mo, (7, 8, and 9 mo) follow-up, mortalities for the top, middle, and bottom sections were 85.2%, 86.3%, and 85.2%, respectively. The results showed that the residual efficacy of Actellic 300CS was up to 9 mo with the first 6 mo exhibiting mortalities of greater than 99% while the next 3 mo showed mortalities exceeding 85%. Actellic 300CS was effective against fully susceptible laboratory-reared Anopheles arabiensis on all four surface types (rough, smooth, dung, and painted surfaces) tested in this study and could be used as one of the chemical insecticides of choice for the ongoing IRS programs in Ethiopia.
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Affiliation(s)
- Sisay Dugassa
- Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia
| | | | | | | | | | - Merga B Feyasa
- Addis Ababa University College of Natural and Computational Sciences, Department of Statistics, Addis Ababa, Ethiopia
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Getaneh A, Yimer M, Alemu M, Dejazmach Z, Alehegn M, Tegegne B. Species Composition, Parous Rate, and Infection Rate of Anopheles Mosquitoes (Diptera: Culicidae) in Bahir Dar City Administration, Northwest Ethiopia. JOURNAL OF MEDICAL ENTOMOLOGY 2021; 58:1874-1879. [PMID: 33822116 DOI: 10.1093/jme/tjab034] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Indexed: 06/12/2023]
Abstract
Anopheles mosquitoes are the main vectors of malaria. There is little information on the current entomological aspects of Anopheles mosquitoes in Amhara region of northwestern Ethiopia. Therefore, the aim of this study was to assess the prevailing species composition, parous rate, and infection rate of Anopheles mosquitoes in the Bahir Dar city administration. A community-based cross-sectional study was conducted from January through July 2020. For this, six Centers for Disease Control and Prevention light traps (three traps indoor and three traps outdoor) were used to collect adult female Anopheles mosquitoes. The species were morphologically identified, and the parous and infection rates were determined via dissection of ovaries and salivary gland, respectively. A total of 378 adult female Anopheles mosquitoes comprised of three species (Anopheles d'thali, Anopheles rhodesiensis, and Anopheles gambiae complex) were collected and identified at the study sites. Anopheles rhodesiensis was the predominant species accounting for 90% of all collections at the Zenzelima site, followed by An. gambiae complex (6.5%). In contrast, An. gambiae complex was the predominant species at the Tis Abay site, comprising 94% of captures. The overall parous and infection rates were 35 (62.5%) and 1 (2.9%), respectively.
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Affiliation(s)
- Abel Getaneh
- Department of Medical Laboratory Sciences, Dessie Health Science College, Dessie, Ethiopia
| | - Mulat Yimer
- Department of Medical Laboratory Sciences, College of Medicine and Health Sciences, Bahir Dar University, Bahir Dar, Ethiopia
| | - Megbaru Alemu
- Department of Medical Laboratory Sciences, College of Medicine and Health Sciences, Bahir Dar University, Bahir Dar, Ethiopia
| | - Zelalem Dejazmach
- Department of Medical Laboratory Sciences, College of Health Sciences,Woldia University, Woldia, Ethiopia
| | - Michael Alehegn
- Department of Medical Laboratory Sciences, College of Medicine and Health Sciences, Bahir Dar University, Bahir Dar, Ethiopia
| | - Banchamlak Tegegne
- Department of Medical Parasitology, Amhara Public Health Institute, Bahir Dar, Ethiopia
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Belay B, Gelana T, Gebresilassie A. Malaria prevalence, knowledge, attitude, and practice among febrile patients attending Chagni health center, Northwest Ethiopia: a cross-sectional study. TROPICAL DISEASES TRAVEL MEDICINE AND VACCINES 2021; 7:20. [PMID: 34218813 PMCID: PMC8256592 DOI: 10.1186/s40794-021-00146-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 06/06/2021] [Indexed: 11/10/2022]
Abstract
Background Ethiopia has achieved considerable progresses in the prevention and control of malaria in the past decades; hitherto it is a formidable health concern and socio-economic impediment. This study aimed at assessing the magnitude, knowledge, attitudes and practices towards malaria among febrile patients attending Chagni health center, northwest Ethiopia. Methods Health facility-based cross-sectional study was conducted to estimate the prevalence of malaria and KAP towards malaria among febrile patients at Chagni health center in Chagni Town during September 2017 to February 2018. In order to determine the magnitude of malaria, finger prick blood samples were collected and thick and thin smears were prepared and microscopically examined for the presence of malaria parasites. A pre-tested structured questionnaire was also applied to assess KAP of suspected malaria patients, attending the health center. Data were analyzed using SPSS version 20.0. Results Prevalence of malaria among febrile patients, who visited the sampled health facility, was 7.3%. Of these, Plasmodium falciparum, P. vivax, and mixed infections accounted for 55, 44.3 and 0.7% of the cases, respectively. This study also revealed that 97% of the respondents had ever heard about malaria and recognized it as a serious health problem. Mosquito bite was identified as the main malaria transmission. Taking drug (86.3%), use of mosquito nets (73.3%), drain stagnated water (68%), and house spay with insecticides (66%) were mentioned as the main malaria prevention methods. Mosquito net coverage and utilizations in the prior night were 98 and 75%, respectively. Indoor residual spraying (IRS) coverage was 99%, of which 77.5% of study participants’ houses have been sprayed in the last 6 months. Conclusions The current study revealed that prevalence of malaria among febrile illnesses in the study area was relatively low (7.3%) with a high proportion of P. falciparum. Besides, participants had adequate knowledge, encouraging attitudes, and good practices about prevention and control of malaria. However, some misconceptions on malaria disease, its transmission, and prevention have been noted that actually require due attention by the concerned stakeholders. The findings of this study could be used as important inputs for the implementation of effective malaria prevention and control methods, including community health education programs, and scaling up coverage of evidence-based interventions. Supplementary Information The online version contains supplementary material available at 10.1186/s40794-021-00146-2.
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Affiliation(s)
- Bogale Belay
- Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Tegenu Gelana
- Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia
| | - Araya Gebresilassie
- Department of Zoological Sciences, Addis Ababa University, Addis Ababa, Ethiopia.
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Degefa T, Githeko AK, Lee MC, Yan G, Yewhalaw D. Patterns of human exposure to early evening and outdoor biting mosquitoes and residual malaria transmission in Ethiopia. Acta Trop 2021; 216:105837. [PMID: 33485868 DOI: 10.1016/j.actatropica.2021.105837] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 01/10/2021] [Accepted: 01/12/2021] [Indexed: 10/22/2022]
Abstract
Ethiopia has shown a notable progress in reducing malaria burden over the past decade, mainly due to the scaleup of vector control interventions such as long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS). Based on the progress, the country has set goals to eliminate malaria by 2030. However, residual malaria transmission due to early evening and outdoor biting vectors could pose a challenge to malaria elimination efforts. This study assessed vector behavior, patterns of human exposure to vector bites and residual malaria transmission in southwestern Ethiopia. Anopheles mosquitoes were collected monthly from January to December 2018 using human landing catches (HLCs), human-baited double net traps, CDC light traps and pyrethrum spray catches. Human behavior data were collected using questionnaire to estimate the magnitude of human exposure to mosquito bites occurring indoors and outdoors at various times of the night. Enzyme-linked immunosorbent assay (ELISA) was used to determine mosquito blood meal sources and sporozoite infections. A total of 2,038 female Anopheles mosquitoes comprising Anopheles arabiensis (30.8%), An. pharoensis (40.5%), An. coustani (28.1%), An. squamosus (0.3%) and An. funestus group (0.2%) were collected. Anopheles arabiensis and An. pharoensis were 2.4 and 2.5 times more likely to seek hosts outdoors than indoors, respectively. However, 66% of human exposure to An. arabiensis and 39% of exposure to An. pharoensis bites occurred indoors for LLIN non-users. For LLIN users, 75% of residual exposure to An. arabiensis bites occurred outdoors while 23% occurred indoors before bed time. Likewise, 84% of residual exposure to An. pharoensis bites occurred outdoors while 15% occurred indoors before people retired to bed. Anopheles arabiensis and An. pharoensis were 4.1 and 4.8 times more likely to feed on bovine than humans, respectively. Based on the HLC, an estimated indoor and outdoor EIR of An. arabiensis was 6.2 and 1.4 infective bites/person/year, respectively, whereas An. pharoensis had an estimated outdoor EIR of 3.0 infective bites/person/year. In conclusion, An. arabiensis and An. pharoensis showed exophagic and zoophagic behavior. Human exposure to An. arabiensis bites occurred mostly indoors for LLIN non-users, while most of the exposure to both An. arabiensis and An. pharoensis bites occurred outdoors for LLIN users. Malaria transmission by An. arabiensis occurred both indoors and outdoors, whereas An. pharoensis contributed exclusively to outdoor transmission. Additional control tools targeting early-evening and outdoor biting malaria vectors are required to complement the current control interventions to control residual transmission and ultimately achieve malaria elimination.
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Campos M, Ward D, Morales RF, Gomes AR, Silva K, Sepúlveda N, Gomez LF, Clark TG, Campino S. Surveillance of Aedes aegypti populations in the city of Praia, Cape Verde: Zika virus infection, insecticide resistance and genetic diversity. Parasit Vectors 2020; 13:481. [PMID: 32958043 PMCID: PMC7507728 DOI: 10.1186/s13071-020-04356-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Accepted: 09/11/2020] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Aedes spp. are responsible for the transmission of many arboviruses, which contribute to rising human morbidity and mortality worldwide. The Aedes aegypti mosquito is a main vector for chikungunya, dengue and yellow fever infections, whose incidence have been increasing and distribution expanding. This vector has also driven the emergence of the Zika virus (ZIKV), first reported in Africa which spread rapidly to Asia and more recently across the Americas. During the outbreak in the Americas, Cape Verde became the first African country declaring a Zika epidemic, with confirmed cases of microcephaly. Here we investigate the prevalence of ZIKV and dengue (DENV) infected Ae. aegypti mosquitoes in the weeks following the outbreak in Cape Verde, and the presence of insecticide resistance in the circulating vector population. Genetic diversity in the mosquito population was also analysed. METHODS From August to October 2016, 816 Ae. aegypti mosquitoes were collected in several locations across Praia, Cape Verde, the major hot spot of reported ZIKV cases in the country. All mosquitoes were screened by reverse transcription PCR for ZIKV and DENV, and a subset (n = 220) were screened for knockdown insecticide resistance associated mutations in the voltage gated sodium channel (VGSC) gene by capillary sequencing. The mitochondrial NADH dehydrogenase subunit 4 (nad4) gene was sequenced in 100 mosquitoes. These data were compared to 977 global sequences in a haplotype network and a phylogenetic tree analysis. RESULTS Two Ae. aegypti mosquitoes were ZIKV positive (0.25%). There were no SNP mutations found in the VGSC gene associated with insecticide resistance. Analysis of the nad4 gene revealed 11 haplotypes in the Cape Verdean samples, with 5 being singletons. Seven haplotypes were exclusive to Cape Verde. Several of the remaining haplotypes were frequent in the global dataset, being present in several countries (including Cape Verde) across five different continents. The most common haplotype in Cape Verde (50.6 %) was also found in Africa and South America. CONCLUSIONS There was low-level Zika virus circulation in mosquitoes from Praia shortly after the outbreak. The Ae. aegypti population did not appear to have the kdr mutations associated with pyrethroid resistance. Furthermore, haplotype and phylogenetic analyses revealed that Cape Verde Ae. aegypti mosquitoes are most closely related to those from other countries in Africa and South America.
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Affiliation(s)
- Monica Campos
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Daniel Ward
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Raika Francesca Morales
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Ana Rita Gomes
- Laboratory of Pathogen-Host Interactions (LPHI), UMR5235, CNRS, Montpellier University, 34095 Montpellier, France
| | - Keily Silva
- Universidade Jean Piaget (UniPiaget), Praia, Cabo Verde
| | - Nuno Sepúlveda
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
- Centre of Statistics and Its Applications of University of Lisbon, Lisbon, Portugal
| | | | - Taane G. Clark
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
- Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK
| | - Susana Campino
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
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Screening of insecticide resistance in Aedes aegypti populations collected from parishes in Eastern Jamaica. PLoS Negl Trop Dis 2020; 14:e0008490. [PMID: 32716942 PMCID: PMC7410332 DOI: 10.1371/journal.pntd.0008490] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 08/06/2020] [Accepted: 06/16/2020] [Indexed: 01/03/2023] Open
Abstract
Owing to the increased reports in Aedes-borne diseases in the Caribbean and Latin America, the United States Agency for International Development assisted the Jamaican Ministry of Health and Wellness in conducting insecticide susceptibility tests on Aedes aegypti populations. Sentinel sites were established in seven parishes of Jamaica (St. Catherine, Kingston and St. Andrew, St. Thomas, Portland, St. Mary and St. Ann) and Aedes aegypti eggs were collected, reared to adults per collected population and their susceptibility to varying pyrethroids and organophosphates were tested using the World Health Organization paper bioassays for these insecticides. The Centers for Disease Control and Prevention bottle bioassay was used to assess susceptibility to the carbamate, bendiocarb. The voltage gated sodium channel gene mutations V1016I and I1011V, normally associated with pyrethroid resistance, were also analysed. The results showed that Aedes aegypti collected from all parishes exhibited resistance to pyrethroids at the following concentrations, permethrin 0.25–2.5%; deltamethrin 0.03–0.15%; lambda-cyhalothrin 0.03–0.3%; and etofenprox 0.5–2.5%. The insecticide deltamethrin at concentration 0.3% was the only pyrethroid tested that resulted in high mortality, 94.9 ± 0.34% knockdown within 1 hour of exposure and 98.95 ± 0.01% mortality (p <0.01) at 24 hours post exposure. The frequency of the voltage gated sodium channel gene mutation V1016I was high in the tested population, possibly accounting for the reduced sensitivity to pyrethroids. Organophosphate resistance was also observed in all populations tested. Mortality rates for 0.8% Malathion was 0.8 ± 0.70–60.68 ± 0.38% after 24 hour and 0.00–47.10 ± 3.02%, for pirimiphos-methyl 0.21%. Bendiocarb applied as 12.5 μg/ bottle resulted in mortality rates of 76.25 ± 4.30–100 ± 0.00% after 30 minutes of exposure. The results showed that Ae. aegypti from the seven parishes analysed demonstrated resistance to the insecticides tested. Deltamethrin and bendiocarb at concentrations 0.3% and 12.5μg respectively, were considered most effective, causing high mortality in the local populations. Routine monitoring and evaluations of Ae. aegypti populations from the included parishes are recommended. Additionally, the study results represent the most comprehensive testing to date with local Aedes aegypti populations distributed across different parishes of Jamaica and should be useful to guide national and sub national strategies for vector control and surveillance. The recent outbreaks of chikungunya, Zika and dengue viruses in the Caribbean and Latin America during 2013–2018, have motivated local health authorities in individual countries to seek international assistance from multiple agencies and adjust their vector management strategies in order to contain the transmission of Aedes-borne diseases. Countries within the region rely mainly on the use of commercially available insecticides to manage the mosquito populations and by extension, reduce the transmission of vector-borne diseases. However, this practice is stymied by the ability of these insects to develop resistance mechanisms to insecticides of frequent use. Many countries in the Caribbean and Latin America regions lack the facilities and supplies to conduct routine insecticide susceptibility testing. In an effort to ascertain knowledge on the presence of insecticide resistance in Aedes aegypti populations, and to determine which insecticide is more effective to reduce vector populations of Jamaica, we conducted an array of bioassays with three different types of insecticides (pyrethroid, organophosphate, carbamate) to use local evidence and inform public health authorities on vector control status and alternatives.
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Hancock PA, Hendriks CJM, Tangena JA, Gibson H, Hemingway J, Coleman M, Gething PW, Cameron E, Bhatt S, Moyes CL. Mapping trends in insecticide resistance phenotypes in African malaria vectors. PLoS Biol 2020; 18:e3000633. [PMID: 32584814 PMCID: PMC7316233 DOI: 10.1371/journal.pbio.3000633] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 05/11/2020] [Indexed: 11/25/2022] Open
Abstract
Mitigating the threat of insecticide resistance in African malaria vector populations requires comprehensive information about where resistance occurs, to what degree, and how this has changed over time. Estimating these trends is complicated by the sparse, heterogeneous distribution of observations of resistance phenotypes in field populations. We use 6,423 observations of the prevalence of resistance to the most important vector control insecticides to inform a Bayesian geostatistical ensemble modelling approach, generating fine-scale predictive maps of resistance phenotypes in mosquitoes from the Anopheles gambiae complex across Africa. Our models are informed by a suite of 111 predictor variables describing potential drivers of selection for resistance. Our maps show alarming increases in the prevalence of resistance to pyrethroids and DDT across sub-Saharan Africa from 2005 to 2017, with mean mortality following insecticide exposure declining from almost 100% to less than 30% in some areas, as well as substantial spatial variation in resistance trends.
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Affiliation(s)
| | | | - Julie-Anne Tangena
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Harry Gibson
- Big Data Institute, University of Oxford, Oxford, United Kingdom
| | - Janet Hemingway
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Michael Coleman
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Peter W. Gething
- Telethon Kids Institute, Perth Children's Hospital, Perth, Australia
- Curtin University, Bentley, Perth, Australia
| | - Ewan Cameron
- Big Data Institute, University of Oxford, Oxford, United Kingdom
| | - Samir Bhatt
- Department of Infectious Disease Epidemiology, Imperial College, St Mary’s Hospital, London, United Kingdom
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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] [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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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: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [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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Menthol Increases Bendiocarb Efficacy Through Activation of Octopamine Receptors and Protein Kinase A. Molecules 2019; 24:molecules24203775. [PMID: 31635151 PMCID: PMC6832705 DOI: 10.3390/molecules24203775] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 10/17/2019] [Accepted: 10/18/2019] [Indexed: 12/31/2022] Open
Abstract
Great effort is put into seeking a new and effective strategies to control insect pests. One of them is to combine natural products with chemical insecticides to increase their effectiveness. In the study presented, menthol which is an essential oil component was evaluated on its ability to increase the efficiency of bendiocarb, carbamate insecticide. A multi-approach study was conducted using biochemical method (to measure acetylcholinesterase enzyme activity), electrophysiological technique (microelectrode recordings in DUM neurons in situ), and confocal microscopy (for calcium imaging). In the electrophysiological experiments, menthol caused hyperpolarization, which was blocked by an octopamine receptor antagonist (phentolamine) and an inhibitor of protein kinase A (H-89). It also raised the intracellular calcium level. The effect of bendiocarb was potentiated by menthol and this phenomenon was abolished by phentolamine and H-89 but not by protein kinase C inhibitor (bisindolylmaleimide IX). The results indicate that menthol increases carbamate insecticide efficiency by acting on octopamine receptors and triggering protein kinase A phosphorylation pathway.
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Oxborough RM, Seyoum A, Yihdego Y, Dabire R, Gnanguenon V, Wat'senga F, Agossa FR, Yohannes G, Coleman S, Samdi LM, Diop A, Faye O, Magesa S, Manjurano A, Okia M, Alyko E, Masendu H, Baber I, Sovi A, Rakotoson JD, Varela K, Abong'o B, Lucas B, Fornadel C, Dengela D. Susceptibility testing of Anopheles malaria vectors with the neonicotinoid insecticide clothianidin; results from 16 African countries, in preparation for indoor residual spraying with new insecticide formulations. Malar J 2019; 18:264. [PMID: 31370898 PMCID: PMC6670198 DOI: 10.1186/s12936-019-2888-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 07/22/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In 2017, more than 5 million house structures were sprayed through the U.S. President's Malaria Initiative, protecting more than 21 million people in sub-Saharan Africa. New IRS formulations, SumiShield™ 50WG and Fludora Fusion™ WP-SB, became World Health Organization (WHO) prequalified vector control products in 2017 and 2018, respectively. Both formulations contain the neonicotinoid active ingredient, clothianidin. The target site of neonicotinoids represents a novel mode of action for vector control, meaning that cross-resistance through existing mechanisms is less likely. In preparation for rollout of clothianidin formulations as part of national IRS rotation strategies, baseline susceptibility testing was conducted in 16 countries in sub-Saharan Africa. METHODS While work coordinated by the WHO is ongoing to develop a suitable bottle bioassay procedure, there was no published guidance regarding clothianidin susceptibility procedures or diagnostic concentrations. Therefore, a protocol was developed for impregnating filter papers with 2% w/v SumiShield™ 50WG dissolved in distilled water. Susceptibility tests were conducted using insectary-reared reference Anopheles and wild collected malaria vector species. All tests were conducted within 24 h of treating papers, with mortality recorded daily for 7 days, due to the slow-acting nature of clothianidin against mosquitoes. Anopheles gambiae sensu lato (s.l.) adults from wild collected larvae were tested in 14 countries, with wild collected F0 Anopheles funestus s.l. tested in Mozambique and Zambia. RESULTS One-hundred percent mortality was reached with all susceptible insectary strains and with wild An. gambiae s.l. from all sites in 11 countries. However, tests in at least one location from 5 countries produced mortality below 98%. While this could potentially be a sign of clothianidin resistance, it is more likely that the diagnostic dose or protocol requires further optimization. Repeat testing in 3 sites in Ghana and Zambia, where possible resistance was detected, subsequently produced 100% mortality. Results showed susceptibility to clothianidin in 38 of the 43 sites in sub-Saharan Africa, including malaria vectors with multiple resistance mechanisms to pyrethroids, carbamates and organophosphates. CONCLUSIONS This study provides an interim diagnostic dose of 2% w/v clothianidin on filter papers which can be utilized by National Malaria Control Programmes and research organizations until the WHO concludes multi-centre studies and provides further guidance.
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Affiliation(s)
- Richard M Oxborough
- PMI VectorLink Project, Abt Associates, 6130 Executive Blvd, Rockville, MD, 20852, USA.
| | - Aklilu Seyoum
- PMI VectorLink Project, Abt Associates, 6130 Executive Blvd, Rockville, MD, 20852, USA
| | - Yemane Yihdego
- PMI VectorLink Project, Abt Associates, 6130 Executive Blvd, Rockville, MD, 20852, USA
| | - Roch Dabire
- Institute of Health Science Research, Malaria and Tropical Neglected Research Unit, 01 BP 545, Bobo-Dioulasso, Burkina Faso
| | - Virgile Gnanguenon
- PMI VectorLink Project, Abt Associates, Plot 28 Avenue Pierre Ngendandumwe, Bujumbura, Burundi
| | - Francis Wat'senga
- Entomology Department, National Institute of Biomedical Research, Avenue de la Démocratie, Kinshasa, Democratic Republic of the Congo
| | - Fiacre R Agossa
- PMI VectorLink Project, Abt Associates, Kinshasa, Democratic Republic of the Congo
| | - Gedeon Yohannes
- PMI VectorLink Project, Abt Associates, Gerje Rood Sami Building, Floor 1, Office no 105, P.O. Box : 13646, Addis Ababa, Ethiopia
| | - Sylvester Coleman
- PMI VectorLink Project, Abt Associates, Plot 11 Waterson Road, Fuo, Tamale, Ghana
| | - Lazarus Musa Samdi
- PMI VectorLink Project, Abt Associates, Gte No. 12, TOS Benson Crescent, Utako, Abuja, Nigeria
| | - Abdoulaye Diop
- PMI VectorLink Project, Abt Associates, Immeuble 8639, Sacré-Couer 2, Dakar Fann, PO Box: 25656, Dakar, Senegal
| | - Ousmane Faye
- Université Cheikh Anta Diop, Département de Biologie Animale, Bp 5005 Dakar-Fann, Dakar, Senegal
| | - Stephen Magesa
- PMI VectorLink Project, Abt Associates, PO Box 1212, Mwanza, Tanzania
| | | | - Michael Okia
- PMI VectorLink Project, Abt Associates, Tororo, Uganda
| | - Evelyne Alyko
- PMI VectorLink Project, Abt Associates, Plot No. 3662, Njoka Road, Off Kwacha Road, Box 39090, Olympia, Lusaka, Zambia
| | - Hieronymo Masendu
- PMI VectorLink Project, Abt Associates, 1 Pascoe Avenue, Belgravia, Harare, Zimbabwe
| | - Ibrahima Baber
- PMI VectorLink Project, Abt Associates, Ministry of Gender Compound, Capitol Bye Pass, Monrovia, Liberia
| | - Arthur Sovi
- PMI VectorLink Project, Abt Associates, Cite du Niger 1, Rue 30, Porte 612, Bamako, Mali
| | - Jean-Desire Rakotoson
- PMI VectorLink Project, Abt Associates, Lot Ex La Sice, Ambalanaomby, Farafangana, Madagascar
| | - Kenyssony Varela
- PMI VectorLink Project, Abt Associates, Rua Orlando Mendes, Nº183, Cidade de Maputo, Mozambique
| | - Bernard Abong'o
- PMI VectorLink Project, Abt Associates, White House, Ojijo Oteko Road, Milimani, Kisumu, Kenya
| | - Bradford Lucas
- PMI VectorLink Project, Abt Associates, 6130 Executive Blvd, Rockville, MD, 20852, USA
| | - Christen Fornadel
- U.S. President's Malaria Initiative, U.S. Agency for International Development, Washington, D.C., USA
| | - Dereje Dengela
- PMI VectorLink Project, Abt Associates, 6130 Executive Blvd, Rockville, MD, 20852, USA
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Simma EA, Dermauw W, Balabanidou V, Snoeck S, Bryon A, Clark RM, Yewhalaw D, Vontas J, Duchateau L, Van Leeuwen T. Genome-wide gene expression profiling reveals that cuticle alterations and P450 detoxification are associated with deltamethrin and DDT resistance in Anopheles arabiensis populations from Ethiopia. PEST MANAGEMENT SCIENCE 2019; 75:1808-1818. [PMID: 30740870 DOI: 10.1002/ps.5374] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 01/18/2019] [Accepted: 02/04/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND Vector control is the main intervention in malaria control and elimination strategies. However, the development of insecticide resistance is one of the major challenges for controlling malaria vectors. Anopheles arabiensis populations in Ethiopia showed resistance against both DDT and the pyrethroid deltamethrin. Although an L1014F target-site resistance mutation was present in the voltage gated sodium channel of investigated populations, the levels of resistance indicated the presence of additional resistance mechanisms. In this study, we used genome-wide transcriptome profiling by RNAseq to assess differentially expressed genes between three deltamethrin and DDT resistant An. arabiensis field populations - Asendabo, Chewaka and Tolay - and two susceptible strains - Sekoru and Mozambique. RESULTS Both RNAseq analysis and RT-qPCR showed that a glutathione-S-transferase, gstd3, and a cytochrome P450 monooxygenase, cyp6p4, were significantly overexpressed in the group of resistant populations compared to the susceptible strains, suggesting that the enzymes they encode play a key role in metabolic resistance against deltamethrin or DDT. Furthermore, a gene ontology enrichment analysis showed that expression changes of cuticle related genes were strongly associated with insecticide resistance. Although this did not translate in increased thickness of the procuticle, a higher cuticular hydrocarbon content was observed in a resistant population. CONCLUSION Our transcriptome sequencing of deltamethrin and DDT resistant An. arabiensis populations from Ethiopia suggests non-target site resistance mechanisms and paves the way for further investigation of the role of cuticle composition in insecticide resistance of malaria vectors. © 2019 Society of Chemical Industry.
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Affiliation(s)
- Eba A Simma
- Department of Biology, College of Natural Sciences, Jimma University, Jimma, Ethiopia
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Wannes Dermauw
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Vasileia Balabanidou
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece
- Department of Biology, University of Crete, Heraklion, Greece
| | - Simon Snoeck
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Astrid Bryon
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Richard M Clark
- School of Biological Sciences, University of Utah, Salt Lake City, UT, USA
- Center for Cell and Genome Science, University of Utah, Salt Lake City, UT, USA
| | - Delenasaw Yewhalaw
- School of Medical Laboratory Sciences, College of Health Sciences, Jimma University, Jimma, Ethiopia
- Tropical and Infectious Diseases Research Center, Jimma University, Jimma, Ethiopia
| | - John Vontas
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion, Greece
- Department of Crop Science, Pesticide Science Lab, Agricultural University of Athens, Athens, Greece
| | - Luc Duchateau
- Department of Nutrition, Genetics and Ethology, Ghent University, Merelbeke, Belgium
| | - Thomas Van Leeuwen
- Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
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Evaluation of toxicity of clothianidin (neonicotinoid) and chlorfenapyr (pyrrole) insecticides and cross-resistance to other public health insecticides in Anopheles arabiensis from Ethiopia. Malar J 2019; 18:49. [PMID: 30795768 PMCID: PMC6387473 DOI: 10.1186/s12936-019-2685-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 02/14/2019] [Indexed: 12/02/2022] Open
Abstract
Background Insecticide-based interventions play an integral role in malaria vector control. However, the continued spread of insecticide resistance threatens to undermine progress made thus far and may ultimately lead to operational failure of current control measures. Clothianidin and chlorfenapyr both have unique modes of action and have expanded the number of insecticide classes available to vector control programmes. Prior to field use, it is imperative to establish their toxicity against local mosquito populations and evaluate potential cross-resistance with other chemicals used contemporarily or historically. The aim of this study was to determine the diagnostic doses of clothianidin and chlorfenapyr and their efficacies against Anopheles arabiensis, the predominant Ethiopian malaria vector species. Methods A range of doses of clothianidin and chlorfenapyr were tested, using modified WHO susceptibility tests and CDC bottle bioassays, respectively, against an Ethiopian susceptible laboratory strain and a wild population of An. arabiensis collected from Oromia Region, Ethiopia. Cross-resistance to other public health insecticides: carbamates (bendiocarb and propoxur), organophosphate (malathion) and pyrethroids (deltamethrin and permethrin), was assessed in the same mosquito populations using CDC bottle bioassays. Results Complete mosquito mortality was observed with the laboratory strain using the recommended diagnostic doses for clothianidin (2%/filter paper) and chlorfenapyr (100 µg/bottle). The field population was resistant to malathion (83% mortality), capable of surviving 2×, 5× and 10× the diagnostic dose of both deltamethrin and permethrin, but susceptible to bendiocarb and propoxur. The field population of An. arabiensis was significantly more susceptible to clothianidin, reaching 100% mortality by day 2 compared to the laboratory strain (100% mortality by day 3). In contrast, the wild population was less susceptible to chlorfenapyr, with the highest mortality of 99% at 72 h using 200 µg/bottle compared to the laboratory colony, which reached complete mortality at 50 µg/bottle by 24 h. Conclusions The putative diagnostic doses of clothianidin and chlorfenapyr are appropriate for monitoring resistance in An. arabiensis from Ethiopia. The unique modes of action and an absence of cross-resistance render clothianidin and chlorfenapyr potential candidates for inclusion in the National Malaria Control Programme vector control efforts, particularly in areas with high pre-existing or emergent resistance to other insecticide classes.
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