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Akambase JA, Ferrão JL, Francisco A, Muhiro V, Novela A, Earland DE, Searle KM. Association of anthelmintic treatment with malaria prevalence in Rural Sussundenga, Mozambique. Wellcome Open Res 2023; 8:417. [PMID: 38623173 PMCID: PMC11018338 DOI: 10.12688/wellcomeopenres.19548.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/22/2023] [Indexed: 04/17/2024] Open
Abstract
Background: Mozambique has the 4 th highest malaria incidence and mortality globally. Despite the existing malaria control strategies, malaria prevalence remains stagnant. These challenges have increased calls for innovative strategies in areas with the highest disease burden. Community mass treatment with anthelmintic agents have been used as an effective tool for the control of major helminth infections and has emerged as a potential tool for vector control in the fight against malaria. Methods: This was an analysis of data from a cross-sectional community-based survey designed to study malaria risk, prevention, and health seeking behaviors in Sussundenga, Mozambique. Using logistic regression models, we quantified the association between ever receiving anthelmintic treatment and P. falciparum infection. We also fit models to determine the association between recent anthelmintic treatment and malaria infection. Results: Two-hundred, seventy-seven (277) participants from 83 households were included in this analysis. The prevalence of P. falciparum infection measured by rapid diagnostic test (RDT) was 30%. 77% of participants reported having ever received anthelmintics. The prevalence of malaria was slightly higher among participants who reported ever taking anthelmintics. There was no statistically significant association between prior receipt of anthelmintic and P. falciparum malaria infection after adjusting for age, ITN use and head of household full-time employment (OR = 1.37, 95% CI, 0.70-2.70, p = 0.36). However, recent intake of anthelmintics was associated with lower odds of testing positive for in the adjusted models (OR = 0.35, 95% CI, 0.07-1.80, p = 0.21), but this was not statistically significant. Conclusions: Our findings show that the benefit of anthelmintics treatment as a control tool for P. falciparum malaria infection is likely tied to when it is administered rather than if it was ever administered. These findings offer evidence for making decisions in planning mass community deworming in sub-Saharan Africa.
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Affiliation(s)
- Joseph A. Akambase
- Epidemiology and Community Health, University of Minnesota Twin Cities, Minneapolis, Minnesota, USA
| | - João L. Ferrão
- Engineering, UniSCED Aberta de Mozambique, Beira, Mozambique
| | | | - Valy Muhiro
- Sussundenge-Sede Centro de Saude Rural, Sussundenga, Mozambique
| | - Anísio Novela
- Sussundenge-Sede Centro de Saude Rural, Sussundenga, Mozambique
| | - Dominique E. Earland
- Epidemiology and Community Health, University of Minnesota Twin Cities, Minneapolis, Minnesota, USA
| | - Kelly M. Searle
- Epidemiology and Community Health, University of Minnesota Twin Cities, Minneapolis, Minnesota, USA
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Holcomb KM, Nguyen C, Foy BD, Ahn M, Cramer K, Lonstrup ET, Mete A, Tell LA, Barker CM. Effects of ivermectin treatment of backyard chickens on mosquito dynamics and West Nile virus transmission. PLoS Negl Trop Dis 2022; 16:e0010260. [PMID: 35333866 PMCID: PMC9012369 DOI: 10.1371/journal.pntd.0010260] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 04/15/2022] [Accepted: 02/14/2022] [Indexed: 11/18/2022] Open
Abstract
Background Vector control strategies typically rely on pesticides to target mosquitoes involved in enzootic and zoonotic transmission of West Nile virus (WNV). Nevertheless, increasing insecticide resistance and a desire to reduce pesticide usage provide the impetus for developing alternative strategies. Ivermectin (IVM), an antiparasitic drug which is widely used in human and veterinary medicine, is a potential alternative for targeted control because Culex mosquitoes experience increased mortality following ingestion of IVM in bloodmeals. Methodology/Principal findings We conducted a randomized field trial to investigate the impact of treating backyard chicken flocks with IVM in urban neighborhoods across Davis, California on mosquito populations and WNV transmission dynamics. We observed a significant reduction in WNV seroconversions in treated vs. untreated chickens, suggesting a reduction in WNV transmission intensity around treated flocks. We also detected a reduction in parity rates of Cx. tarsalis near treated vs. untreated flocks and increased mortality in wild mosquitoes following a bloodmeal on treated chickens (IVM serum concentration > 5ng/mL) vs. chickens with IVM serum concentrations < 5 ng/mL. However, we did not find a significant difference in abundance or infection prevalence in mosquitoes between treatment groups associated with the reductions in seroconversions. Mosquito immigration from surrounding larval habitat, relatively low WNV activity in the study area, and variable IVM serum concentrations likely contributed to uncertainty about the impact. Conclusions/Significance Taken together, our results point to a reduction in WNV transmission due to the impact of IVM on Culex mosquito populations and support the ongoing investigation of oral administration of IVM to wild birds for local control of WNV transmission, although further work is needed to optimize dosing and understand effects on entomological endpoints. Current mosquito control strategies aimed to prevent pathogen transmission to humans have limited ability to target mosquitoes involved in amplification and spillover transmission of pathogens like West Nile virus (WNV). Additionally, growing prevalence of insecticide resistance in mosquito populations limit the efficacy of these insecticide-based control strategies. Ivermectin (IVM) provides an alternative avenue for control by increasing the mortality of mosquitoes that ingest this drug in bloodmeals. Therefore, IVM treatment of avian species that account for the majority of mosquito bloodmeals during the WNV transmission season could be an effective control strategy. Building on pilot studies indicating the efficacy and feasibility of IVM-deployment for WNV control, we performed a randomized field trial to investigate the impact of IVM-treatment of backyard chickens on local population dynamics of Culex mosquitoes and WNV transmission. We were able to link changes in mosquito populations to reduction in WNV transmission, as measured by chicken seroconversions, through IVM-induced mortality in mosquitoes. However, further work is needed to identify the impact of treatment on mosquito abundance and infection prevalence to fully attribute observed changes to IVM administration. Overall, our results support IVM treatment as a potentially effective alternative to insecticide-based vector control strategies and one that can be used to target WNV transmission on the local scale.
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Affiliation(s)
- Karen M. Holcomb
- Davis Arbovirus Research and Training Laboratory, Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - Chilinh Nguyen
- Center for Vector-borne Infectious Diseases, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Brian D. Foy
- Center for Vector-borne Infectious Diseases, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Michelle Ahn
- Davis Arbovirus Research and Training Laboratory, Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - Kurt Cramer
- Davis Arbovirus Research and Training Laboratory, Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - Emma T. Lonstrup
- Davis Arbovirus Research and Training Laboratory, Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - Asli Mete
- California Animal Health and Food Safety Lab, Department of Pathology, Microbiology & Immunology, University of California, Davis, California, United States of America
| | - Lisa A. Tell
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - Christopher M. Barker
- Davis Arbovirus Research and Training Laboratory, Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, California, United States of America
- * E-mail:
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3
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Kositz C, Bradley J, Hutchins H, Last A, D'Alessandro U, Marks M. Broadening the range of use cases for ivermectin - a review of the evidence. Trans R Soc Trop Med Hyg 2022; 116:201-212. [PMID: 34323283 PMCID: PMC8890779 DOI: 10.1093/trstmh/trab114] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 06/30/2021] [Accepted: 07/13/2021] [Indexed: 11/12/2022] Open
Abstract
Ivermectin is a broad-spectrum antiparasitic agent that interferes with glutamate-gated chloride channels found in invertebrates but not in vertebrate species. Mass drug administration (MDA) with ivermectin-based regimes has been a mainstay of elimination efforts targeting onchocerciasis and lymphatic filariasis for more than 3 decades. More recently, interest in the use of ivermectin to control other neglected tropical diseases (NTDs) such as soil-transmitted helminths and scabies has grown. Interest has been further stimulated by the fact that ivermectin displays endectocidal efficacy against various Anopheles species capable of transmitting malaria. Therefore there is growing interest in using ivermectin MDA as a tool that might aid in the control of both malaria and several NTDs. In this review we outline the evidence base to date on these emerging indications for ivermectin MDA with reference to clinical and public health data and discuss the rationale for evaluating the range of impacts of a malaria ivermectin MDA on other NTDs.
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Affiliation(s)
- Christian Kositz
- Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, WC1E 7HT, London, UK
| | - John Bradley
- MRC International Statistics and Epidemiology Group, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, Keppel Street, WC1E 7HT, London, UK
| | - Harry Hutchins
- Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, WC1E 7HT, London, UK
| | - Anna Last
- Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, WC1E 7HT, London, UK
- Hospital for Tropical Diseases, Mortimer Market Capper Street, WC1E 6JB, London, UK
| | - Umberto D'Alessandro
- Disease Control and Elimination, Medical Research Council Unit Gambia at London School of Hygiene and Tropical Medicine, Atlantic Boulevard, Fajara, The Gambia
| | - Michael Marks
- Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, WC1E 7HT, London, UK
- Hospital for Tropical Diseases, Mortimer Market Capper Street, WC1E 6JB, London, UK
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Zhou S, Wu H, Ning W, Wu X, Xu X, Ma Y, Li X, Hu J, Wang C, Wang J. Ivermectin has New Application in Inhibiting Colorectal Cancer Cell Growth. Front Pharmacol 2021; 12:717529. [PMID: 34483925 PMCID: PMC8415024 DOI: 10.3389/fphar.2021.717529] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 08/05/2021] [Indexed: 01/05/2023] Open
Abstract
Colorectal cancer (CRC) is the third most common cancer worldwide and still lacks effective therapy. Ivermectin, an antiparasitic drug, has been shown to possess anti-inflammation, anti-virus, and antitumor properties. However, whether ivermectin affects CRC is still unclear. The objective of this study was to evaluate the influence of ivermectin on CRC using CRC cell lines SW480 and SW1116. We used CCK-8 assay to determine the cell viability, used an optical microscope to measure cell morphology, used Annexin V-FITC/7-AAD kit to determine cell apoptosis, used Caspase 3/7 Activity Apoptosis Assay Kit to evaluate Caspase 3/7 activity, used Western blot to determine apoptosis-associated protein expression, and used flow cytometry and fluorescence microscope to determine the reactive oxygen species (ROS) levels and cell cycle. The results demonstrated that ivermectin dose-dependently inhibited colorectal cancer SW480 and SW1116 cell growth, followed by promoting cell apoptosis and increasing Caspase-3/7 activity. Besides, ivermectin upregulated the expression of proapoptotic proteins Bax and cleaved PARP and downregulated antiapoptotic protein Bcl-2. Mechanism analysis showed that ivermectin promoted both total and mitochondrial ROS production in a dose-dependent manner, which could be eliminated by administering N-acetyl-l-cysteine (NAC) in CRC cells. Following NAC treatment, the inhibition of cell growth induced by ivermectin was reversed. Finally, ivermectin at low doses (2.5 and 5 µM) induced CRC cell arrest. Overall, ivermectin suppressed cell proliferation by promoting ROS-mediated mitochondrial apoptosis pathway and inducing S phase arrest in CRC cells, suggesting that ivermectin might be a new potential anticancer drug therapy for human colorectal cancer and other cancers.
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Affiliation(s)
- Shican Zhou
- Infection and Immunity Institute and Translational Medical Center of Huaihe Hospital, Henan University, Kaifeng, China
| | - Hang Wu
- Infection and Immunity Institute and Translational Medical Center of Huaihe Hospital, Henan University, Kaifeng, China
| | - Wenjuan Ning
- Infection and Immunity Institute and Translational Medical Center of Huaihe Hospital, Henan University, Kaifeng, China
| | - Xiao Wu
- Infection and Immunity Institute and Translational Medical Center of Huaihe Hospital, Henan University, Kaifeng, China
| | - Xiaoxiao Xu
- Infection and Immunity Institute and Translational Medical Center of Huaihe Hospital, Henan University, Kaifeng, China
| | - Yuanqiao Ma
- Infection and Immunity Institute and Translational Medical Center of Huaihe Hospital, Henan University, Kaifeng, China
| | - Xingwang Li
- Infection and Immunity Institute and Translational Medical Center of Huaihe Hospital, Henan University, Kaifeng, China
| | - Junhong Hu
- Infection and Immunity Institute and Translational Medical Center of Huaihe Hospital, Henan University, Kaifeng, China
| | - Chenyu Wang
- Infection and Immunity Institute and Translational Medical Center of Huaihe Hospital, Henan University, Kaifeng, China
| | - Junpeng Wang
- Infection and Immunity Institute and Translational Medical Center of Huaihe Hospital, Henan University, Kaifeng, China
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Badia-Rius X, Betts H, Wanji S, Molyneux D, Taylor MJ, Kelly-Hope LA. Environmental Factors Associated With Loa loa Microfilaria Prevalence and Intensity in Diverse Bioecological Zones of Cameroon. FRONTIERS IN TROPICAL DISEASES 2021. [DOI: 10.3389/fitd.2021.668641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Loiasis (African Eye Worm) is a filarial infection caused by Loa loa and transmitted by Chrysops vectors, which are confined to the tropical rainforests of Central and West Africa. Loiasis is a major impediment to control and elimination programmes that use the drug ivermectin due to the risk of serious adverse events. There is an urgent need to better refine and map high-risk communities. This study aimed to quantify and predict environmental factors associated with loiasis across five bioecological zones in Cameroon. The L. loa microfilaria (mf) prevalence (%) and intensity (mf number/ml) data from 42 villages within an Equatorial Rainforest and Savannah region were examined in relation to climate, topographic and forest-related data derived from satellite remote sensing sources. Differences between zones and regions were examined using nonparametric tests, and the relationship between L. loa mf prevalence, mf intensity, and the environmental factors using polynomial regression models. Overall, the L. loa mf prevalence was 11.6%, L. loa intensity 927.4 mf/ml, mean annual temperature 23.7°C, annual precipitation 2143.2 mm, elevation 790 m, tree canopy cover 46.7%, and canopy height 19.3m. Significant differences between the Equatorial Rainforest and Savannah region were found. Within the Equatorial Rainforest region, no significant differences were found. However, within the Savannah region, significant differences between the three bioecological zones were found, and the regression models indicated that tree canopy cover and elevation were significant predictors, explaining 85.1% of the L. loa mf prevalence (adjusted R2 = 0.851; p<0.001) and tree cover alone was significant, explaining 58.1% of the mf intensity (adjusted R2 = 0.581; p<0.001). The study highlights that environmental analysis can help delineate risk at different geographical scales, which may be practical for developing larger scale operational plans for mapping and implementing safe effective interventions.
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Fehr A, Nieto-Sanchez C, Muela J, Jaiteh F, Ceesay O, Maneh E, Baldeh D, Achan J, Dabira E, Conteh B, Bunders-Aelen J, Smekens T, Broekhuizen H, D'Alessandro U, Peeters Grietens K. From informed consent to adherence: factors influencing involvement in mass drug administration with ivermectin for malaria elimination in The Gambia. Malar J 2021; 20:198. [PMID: 33902611 PMCID: PMC8073909 DOI: 10.1186/s12936-021-03732-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 04/08/2021] [Indexed: 11/29/2022] Open
Abstract
Background The World Health Organization (WHO) recommends consideration of mass drug administration (MDA) for malaria control in low-endemic settings approaching elimination. However, MDA remains a controversial strategy, as multiple individual, social, and operational factors have shown to affect its acceptability at local levels. This is further complicated by inconsistent definitions of key indicators derived from individual and community involvement—coverage, adherence, and compliance—that cast doubts about the actual and potential epidemiological impact of MDA on disease control and elimination. This study aimed to identify limitations and enabling factors impacting involvement at different stages of a large cluster-randomized trial assessing the effect of combining dihydroartemisinin-piperaquine (DP) and ivermectin (IVM) in malaria transmission in The Gambia. Methods This social science study used a mixed-methods approach. Qualitative data were collected in intervention and control villages through ethnographic methods, including in-depth interviews (IDIs), focus group discussions (FGDs), and participant observation conducted with trial participants and decliners, community leaders, and field staff. A cross-sectional survey was conducted in the intervention villages after the first year of MDA. Both strands of the study explored malaria knowledge and opinions, social dynamics influencing decision-making, as well as perceived risks, burdens, and benefits associated with this MDA. Results 157 IDIs and 11 FGDs were conducted, and 864 respondents were included in the survey. Barriers and enabling factors to involvement were differentially influential at the various stages of the MDA. Issues of social influence, concerns regarding secondary effects of the medication, costs associated with malaria, and acceptability of the implementing organization, among other factors, differently affected the decision-making processes throughout the trial. Rather than a linear trajectory, involvement in this MDA trial was subjected to multiple revaluations from enrolment and consent to medicine intake and adherence to treatment. Conclusions This study went beyond the individual factors often associated with coverage and adherence, and found that nuanced social dynamics greatly influence the decision-making process at all phases of the trial. These issues need to be consider for MDA implementation strategies and inform discussions about more accurate ways of reporting on critical effectiveness indicators. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-021-03732-z.
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Affiliation(s)
- Alexandra Fehr
- Athena Institute, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
| | - Claudia Nieto-Sanchez
- Unit of Socio-Ecological Health Research, Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium
| | - Joan Muela
- Medical Anthropology Research Center, Universitat Rovira I Virgill, Tarragona, Spain
| | - Fatou Jaiteh
- Unit of Socio-Ecological Health Research, Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium
| | - Omar Ceesay
- Medical Research Council Unit Gambia at London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Ebrima Maneh
- Medical Research Council Unit Gambia at London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Dullo Baldeh
- Medical Research Council Unit Gambia at London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Jane Achan
- Medical Research Council Unit Gambia at London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Edgard Dabira
- Medical Research Council Unit Gambia at London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Bakary Conteh
- Medical Research Council Unit Gambia at London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | | | - Tom Smekens
- Unit of Socio-Ecological Health Research, Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium
| | | | - Umberto D'Alessandro
- Medical Research Council Unit Gambia at London School of Hygiene and Tropical Medicine, Fajara, The Gambia
| | - Koen Peeters Grietens
- Unit of Socio-Ecological Health Research, Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium
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7
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Nicolas P, Kiuru C, Wagah MG, Muturi M, Duthaler U, Hammann F, Maia M, Chaccour C. Potential metabolic resistance mechanisms to ivermectin in Anopheles gambiae: a synergist bioassay study. Parasit Vectors 2021; 14:172. [PMID: 33743783 PMCID: PMC7981804 DOI: 10.1186/s13071-021-04675-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 03/07/2021] [Indexed: 11/10/2022] Open
Abstract
Background Despite remarkable success obtained with current malaria vector control strategies in the last 15 years, additional innovative measures will be needed to achieve the ambitious goals for malaria control set for 2030 by the World Health Organization (WHO). New tools will need to address insecticide resistance and residual transmission as key challenges. Endectocides such as ivermectin are drugs that kill mosquitoes which feed on treated subjects. Mass administration of ivermectin can effectively target outdoor and early biting vectors, complementing the still effective conventional tools. Although this approach has garnered attention, development of ivermectin resistance is a potential pitfall. Herein, we evaluate the potential role of xenobiotic pumps and cytochrome P450 enzymes in protecting mosquitoes against ivermectin by active efflux and metabolic detoxification, respectively. Methods We determined the lethal concentration 50 for ivermectin in colonized Anopheles gambiae; then we used chemical inhibitors and inducers of xenobiotic pumps and cytochrome P450 enzymes in combination with ivermectin to probe the mechanism of ivermectin detoxification. Results Dual inhibition of xenobiotic pumps and cytochromes was found to have a synergistic effect with ivermectin, greatly increasing mosquito mortality. Inhibition of xenobiotic pumps alone had no effect on ivermectin-induced mortality. Induction of xenobiotic pumps and cytochromes may confer partial protection from ivermectin. Conclusion There is a clear pathway for development of ivermectin resistance in malaria vectors. Detoxification mechanisms mediated by cytochrome P450 enzymes are more important than xenobiotic pumps in protecting mosquitoes against ivermectin.![]()
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Affiliation(s)
- Patricia Nicolas
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Rosello 132, 5ª 2ª, 08036, Barcelona, Spain.,Centro de Investigação em Saúde de Manhiça, 1929, Maputo, Mozambique
| | - Caroline Kiuru
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Rosello 132, 5ª 2ª, 08036, Barcelona, Spain.,Centro de Investigação em Saúde de Manhiça, 1929, Maputo, Mozambique
| | - Martin G Wagah
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 91SA, UK.,Department of Biosciences, KEMRI Wellcome Trust Research Programme, Kilifi, 230-80108, Kenya
| | - Martha Muturi
- Department of Biosciences, KEMRI Wellcome Trust Research Programme, Kilifi, 230-80108, Kenya
| | - Urs Duthaler
- Division of Clinical Pharmacology and Toxicology, Department of Biomedicine, University and University Hospital Basel, 4056, Basel, Switzerland.,Division of Clinical Pharmacology and Toxicology, Department of Pharmaceutical Sciences, University of Basel, 4056, Basel, Switzerland
| | - Felix Hammann
- Division of Clinical Pharmacology and Toxicology, Department of Internal Medicine, University Hospital Bern, 3010, Bern, Switzerland
| | - Marta Maia
- Department of Biosciences, KEMRI Wellcome Trust Research Programme, Kilifi, 230-80108, Kenya.,Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
| | - Carlos Chaccour
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Rosello 132, 5ª 2ª, 08036, Barcelona, Spain. .,Ifakara Health Institute, Ifakara, 67501, United Republic of Tanzania. .,Facultad de Medicina, Universidad de Navarra, 31008, Pamplona, Spain.
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8
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Ashley EA, Poespoprodjo JR. Treatment and prevention of malaria in children. THE LANCET CHILD & ADOLESCENT HEALTH 2020; 4:775-789. [PMID: 32946831 DOI: 10.1016/s2352-4642(20)30127-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 03/11/2020] [Accepted: 03/25/2020] [Indexed: 10/23/2022]
Abstract
Malaria disproportionately affects children younger than 5 years. Falciparum malaria is responsible for more than 200 000 child deaths per year in Africa and vivax malaria is well documented as a cause of severe anaemia and excess mortality in children in Asia and Oceania. For the treatment of malaria in children, paediatric dosing recommendations for several agents, including parenteral artesunate and dihydroartemisinin-piperaquine, have belatedly been shown to be suboptimal. Worsening antimalarial resistance in Plasmodium falciparum in the Greater Mekong Subregion threatens to undermine global efforts to control malaria. Triple antimalarial combination therapies are being evaluated to try to impede this threat. The RTS,S/AS01 vaccine gives partial protection against falciparum malaria and is being evaluated in large, pilot studies in Ghana, Malawi, and Kenya as a complementary tool to other preventive measures. Seasonal malaria chemoprevention in west Africa has resulted in declines in malaria incidence and deaths and there is interest in scaling up efforts by expanding the age range of eligible recipients. Preventing relapse in Plasmodium vivax infection with primaquine is challenging because treating children who have G6PD deficiency with primaquine can cause acute haemolytic anaemia. The safety of escalating dose regimens for primaquine is being studied to mitigate this risk.
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Affiliation(s)
- Elizabeth A Ashley
- Lao-Oxford-Mahosot Hospital-Wellcome Trust Research Unit, Vientiane, Laos; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
| | - Jeanne Rini Poespoprodjo
- Timika Research Facility, Papuan Health and Community Development Foundation, Timika, Indonesia; Department of Child Health, Faculty of Medicine, Public Health and Nursing, Gadjah Mada University, Yogyakarta, Indonesia
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9
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Finda MF, Christofides N, Lezaun J, Tarimo B, Chaki P, Kelly AH, Kapologwe N, Kazyoba P, Emidi B, Okumu FO. Opinions of key stakeholders on alternative interventions for malaria control and elimination in Tanzania. Malar J 2020; 19:164. [PMID: 32321534 PMCID: PMC7178586 DOI: 10.1186/s12936-020-03239-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 04/16/2020] [Indexed: 03/03/2023] Open
Abstract
Background Malaria control in Tanzania currently relies primarily on long-lasting insecticidal nets and indoor residual spraying, alongside effective case management and behaviour change communication. This study explored opinions of key stakeholders on the national progress towards malaria elimination, the potential of currently available vector control interventions in helping achieve elimination by 2030, and the need for alternative interventions that could be used to supplement malaria elimination efforts in Tanzania. Methods In this exploratory qualitative study, Focus group discussions were held with policy-makers, regulators, research scientists and community members. Malaria control interventions discussed were: (a) improved housing, (b) larval source management, (c) mass drug administration (MDA) with ivermectin to reduce vector densities, (d) release of modified mosquitoes, including genetically modified or irradiated mosquitoes, (e) targeted spraying of mosquito swarms, and (f) spatial repellents. Results Larval source management and spatial repellents were widely supported across all stakeholder groups, while insecticide-spraying of mosquito swarms was the least preferred. Support for MDA with ivermectin was high among policy makers, regulators and research scientists, but encountered opposition among community members, who instead expressed strong support for programmes to improve housing for poor people in high transmission areas. Policy makers, however, challenged the idea of government-supported housing improvement due to its perceived high costs. Techniques of mosquito modification, specifically those involving gene drives, were viewed positively by community members, policy makers and regulators, but encountered a high degree of scepticism among scientists. Overall, policy-makers, regulators and community members trusted scientists to provide appropriate advice for decision-making. Conclusion Stakeholder opinions regarding alternative malaria interventions were divergent except for larval source management and spatial repellents, for which there was universal support. MDA with ivermectin, housing improvement and modified mosquitoes were also widely supported, though each faced concerns from at least one stakeholder group. While policy-makers, regulators and community members all noted their reliance on scientists to make informed decisions, their reasoning on the benefits and disadvantages of specific interventions included factors beyond technical efficiency. This study suggests the need to encourage and strengthen dialogue between research scientists, policy makers, regulators and communities regarding new interventions.
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Affiliation(s)
- Marceline F Finda
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania. .,School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, 1 Smuts Avenue, Braamfontein, 2000, South Africa.
| | - Nicola Christofides
- School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, 1 Smuts Avenue, Braamfontein, 2000, South Africa
| | - Javier Lezaun
- Institute for Science, Innovation and Society, School of Anthropology and Museum Ethnography, University of Oxford, Oxford, UK
| | - Brian Tarimo
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania
| | - Prosper Chaki
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania
| | - Ann H Kelly
- Department of Global Health and Social Medicine, King's College, London, UK
| | - Ntuli Kapologwe
- President's Office, Regional Administration and Local Government, P. O Box 1923, Dodoma, Tanzania
| | - Paul Kazyoba
- National Institute for Medical Research, 3 Barack Obama Drive, Dar es Salaam, Tanzania
| | - Basiliana Emidi
- National Institute for Medical Research, 3 Barack Obama Drive, Dar es Salaam, Tanzania.,National Malaria Control Programme, P. O. Box 743, Dodoma, Tanzania
| | - Fredros O Okumu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, P. O. Box 53, Ifakara, Tanzania.,School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, 1 Smuts Avenue, Braamfontein, 2000, South Africa.,Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, G12 8QQ, UK.,School of Life Science and Bioengineering, The Nelson Mandela African Institution of Science and Technology, P. O. Box 447, Arusha, Tanzania
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10
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Production and computational fluid dynamics-based modeling of PMMA nanoparticles impregnated with ivermectin by a supercritical antisolvent process. J CO2 UTIL 2020. [DOI: 10.1016/j.jcou.2019.08.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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11
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Abdeltawab MSA, Rifaie SA, Shoeib EY, El-Latif HAA, Badawi M, Salama WH, El-Aal AAA. Insights into the impact of Ivermectin on some protein aspects linked to Culex pipiens digestion and immunity. Parasitol Res 2019; 119:55-62. [DOI: 10.1007/s00436-019-06539-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 11/03/2019] [Indexed: 02/08/2023]
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12
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Meredith HR, Furuya-Kanamori L, Yakob L. Optimising systemic insecticide use to improve malaria control. BMJ Glob Health 2019; 4:e001776. [PMID: 31798988 PMCID: PMC6861066 DOI: 10.1136/bmjgh-2019-001776] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Revised: 09/26/2019] [Accepted: 10/12/2019] [Indexed: 01/08/2023] Open
Abstract
Background Long-lasting insecticidal nets and indoor residual sprays have significantly reduced the burden of malaria. However, several hurdles remain before elimination can be achieved: mosquito vectors have developed resistance to public health insecticides, including pyrethroids, and have altered their biting behaviour to avoid these indoor control tools. Systemic insecticides, drugs applied directly to blood hosts to kill mosquitoes that take a blood meal, offer a promising vector control option. To date, most studies focus on repurposing ivermectin, a drug used extensively to treat river blindness. There is concern that overdependence on a single drug will inevitably repeat past experiences with the rapid spread of pyrethroid resistance in malaria vectors. Diversifying the arsenal of systemic insecticides used for mass drug administration would improve this strategy’s sustainability. Methods Here, a review was conducted to identify systemic insecticide candidates and consolidate their pharmacokinetic/pharmacodynamic properties. The impact of alternative integrated vector control options and different dosing regimens on malaria transmission reduction are illustrated through mathematical model simulation. Results The review identified drugs from four classes commonly used in livestock and companion animals: avermectins, milbemycins, isoxazolines and spinosyns. Simulations predicted that isoxazolines and spinosyns are promising candidates for mass drug administration, as they were predicted to need less frequent application than avermectins and milbemycins to maintain mosquitocidal blood concentrations. Conclusions These findings will provide a guide for investigating and applying different systemic insecticides to achieve more effective and sustainable control of malaria transmission.
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Affiliation(s)
- Hannah R Meredith
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.,Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Luis Furuya-Kanamori
- Research School of Population Health, College of Health and Medicine, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Laith Yakob
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
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13
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Miglianico M, Eldering M, Slater H, Ferguson N, Ambrose P, Lees RS, Koolen KMJ, Pruzinova K, Jancarova M, Volf P, Koenraadt CJM, Duerr HP, Trevitt G, Yang B, Chatterjee AK, Wisler J, Sturm A, Bousema T, Sauerwein RW, Schultz PG, Tremblay MS, Dechering KJ. Repurposing isoxazoline veterinary drugs for control of vector-borne human diseases. Proc Natl Acad Sci U S A 2018; 115:E6920-E6926. [PMID: 29967151 PMCID: PMC6055183 DOI: 10.1073/pnas.1801338115] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Isoxazolines are oral insecticidal drugs currently licensed for ectoparasite control in companion animals. Here we propose their use in humans for the reduction of vector-borne disease incidence. Fluralaner and afoxolaner rapidly killed Anopheles, Aedes, and Culex mosquitoes and Phlebotomus sand flies after feeding on a drug-supplemented blood meal, with IC50 values ranging from 33 to 575 nM, and were fully active against strains with preexisting resistance to common insecticides. Based on allometric scaling of preclinical pharmacokinetics data, we predict that a single human median dose of 260 mg (IQR, 177-407 mg) for afoxolaner, or 410 mg (IQR, 278-648 mg) for fluralaner, could provide an insecticidal effect lasting 50-90 days against mosquitoes and Phlebotomus sand flies. Computational modeling showed that seasonal mass drug administration of such a single dose to a fraction of a regional population would dramatically reduce clinical cases of Zika and malaria in endemic settings. Isoxazolines therefore represent a promising new component of drug-based vector control.
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Affiliation(s)
| | | | - Hannah Slater
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London SW7 2AZ, United Kingdom
| | - Neil Ferguson
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London SW7 2AZ, United Kingdom
| | - Pauline Ambrose
- The Liverpool Insect Testing Establishment, Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom
| | - Rosemary S Lees
- The Liverpool Insect Testing Establishment, Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom
| | | | - Katerina Pruzinova
- Department of Parasitology, Faculty of Science, Charles University, 116 36 Prague, Czech Republic
| | - Magdalena Jancarova
- Department of Parasitology, Faculty of Science, Charles University, 116 36 Prague, Czech Republic
| | - Petr Volf
- Department of Parasitology, Faculty of Science, Charles University, 116 36 Prague, Czech Republic
| | | | | | | | - Baiyuan Yang
- California Institute for Biomedical Research, La Jolla, CA 92037
| | | | - John Wisler
- California Institute for Biomedical Research, La Jolla, CA 92037
| | | | - Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Center, 6525 Nijmegen, The Netherlands
| | - Robert W Sauerwein
- TropIQ Health Sciences, 6534 Nijmegen, The Netherlands
- Department of Medical Microbiology, Radboud University Medical Center, 6525 Nijmegen, The Netherlands
| | - Peter G Schultz
- California Institute for Biomedical Research, La Jolla, CA 92037;
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14
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Abstract
The last two decades have seen a surge in antimalarial drug development with product development partnerships taking a leading role. Resistance of Plasmodium falciparum to the artemisinin derivatives, piperaquine and mefloquine in Southeast Asia means new antimalarials are needed with some urgency. There are at least 13 agents in clinical development. Most of these are blood schizonticides for the treatment of uncomplicated falciparum malaria, under evaluation either singly or as part of two-drug combinations. Leading candidates progressing through the pipeline are artefenomel-ferroquine and lumefantrine-KAF156, both in Phase 2b. Treatment of severe malaria continues to rely on two parenteral drugs with ancient forebears: artesunate and quinine, with sevuparin being evaluated as an adjuvant therapy. Tafenoquine is under review by stringent regulatory authorities for approval as a single-dose treatment for Plasmodium vivax relapse prevention. This represents an advance over standard 14-day primaquine regimens; however, the risk of acute haemolytic anaemia in patients with glucose-6-phosphate dehydrogenase deficiency remains. For disease prevention, several of the newer agents show potential but are unlikely to be recommended for use in the main target groups of pregnant women and young children for some years. Latest predictions are that the malaria burden will continue to be high in the coming decades. This fact, coupled with the repeated loss of antimalarials to resistance, indicates that new antimalarials will be needed for years to come. Failure of the artemisinin-based combinations in Southeast Asia has stimulated a reappraisal of current approaches to combination therapy for malaria with incorporation of three or more drugs in a single treatment under consideration.
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Affiliation(s)
- Elizabeth A Ashley
- Myanmar Oxford Clinical Research Unit, Yangon, Myanmar.
- Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK.
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15
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Abstract
Following unsuccessful eradication attempts there was a resurgence of malaria towards the end of the 20th century. Renewed control efforts using a range of improved tools, such as long-lasting insecticide-treated bednets and artemisinin-based combination therapies, have more than halved the global burden of disease, but it remains high with 445 000 deaths and more than 200 million cases in 2016. Pitfalls in individual patient management are delayed diagnosis and overzealous fluid resuscitation in severe malaria. Even in the absence of drug resistance, parasite recurrence can occur, owing to high parasite densities, low host immunity, or suboptimal drug concentrations. Malaria elimination is firmly back as a mainstream policy but resistance to the artemisinin derivatives, their partner drugs, and insecticides present major challenges. Vaccine development continues on several fronts but none of the candidates developed to date have been shown to provide long-lasting benefits at a population level. Increased resources and unprecedented levels of regional cooperation and societal commitment will be needed if further substantial inroads into the malaria burden are to be made.
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Affiliation(s)
- Elizabeth A Ashley
- Myanmar-Oxford Clinical Research Unit, Yangon, Myanmar; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
| | - Aung Pyae Phyo
- Shoklo Malaria Research Unit, Mae Sot, Thailand; Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Charles J Woodrow
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK; Mahidol-Oxford Tropical Medicine Research Unit (MORU), Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
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16
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Ivermectin susceptibility and sporontocidal effect in Greater Mekong Subregion Anopheles. Malar J 2017; 16:280. [PMID: 28687086 PMCID: PMC5501099 DOI: 10.1186/s12936-017-1923-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 06/28/2017] [Indexed: 12/26/2022] Open
Abstract
Background Novel vector control methods that can directly target outdoor malaria transmission are urgently needed in the Greater Mekong Subregion (GMS) to accelerate malaria elimination and artemisinin resistance containment efforts. Ivermectin mass drug administration (MDA) to humans has been shown to effectively kill wild Anopheles and suppress malaria transmission in West Africa. Preliminary laboratory investigations were performed to determine ivermectin susceptibility and sporontocidal effect in GMS Anopheles malaria vectors coupled with pharmacokinetic models of ivermectin at escalating doses. Methods A population-based pharmacokinetic model of ivermectin was developed using pre-existing data from a clinical trial conducted in Thai volunteers at the 200 µg/kg dose. To assess ivermectin susceptibility, various concentrations of ivermectin compound were mixed in human blood meals and blood-fed to Anopheles dirus, Anopheles minimus, Anopheles sawadwongporni, and Anopheles campestris. Mosquito survival was monitored daily for 7 days and a non-linear mixed effects model with probit analyses was used to calculate concentrations of ivermectin that killed 50% (LC50) of mosquitoes for each species. Blood samples were collected from Plasmodium vivax positive patients and offered to mosquitoes with or without ivermectin at the ivermectin LC25 or LC5 for An. dirus and An. minimus. Results The GMS Anopheles displayed a range of susceptibility to ivermectin with species listed from most to least susceptible being An. minimus (LC50 = 16.3 ng/ml) > An. campestris (LC50 = 26.4 ng/ml) = An. sawadwongporni (LC50 = 26.9 ng/ml) > An. dirus (LC50 = 55.6 ng/ml). Mosquito survivorship results, the pharmacokinetic model, and extensive safety data indicated that ivermectin 400 µg/kg is the ideal minimal dose for MDA in the GMS for malaria parasite transmission control. Ivermectin compound was sporontocidal to P. vivax in both An. dirus and An. minimus at the LC25 and LC5 concentrations. Conclusions Ivermectin is lethal to dominant GMS Anopheles malaria vectors and inhibits sporogony of P. vivax at safe human relevant concentrations. The data suggest that ivermectin MDA has potential in the GMS as a vector and transmission blocking control tool to aid malaria elimination efforts. Electronic supplementary material The online version of this article (doi:10.1186/s12936-017-1923-8) contains supplementary material, which is available to authorized users.
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17
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Alout H, Labbé P, Chandre F, Cohuet A. Malaria Vector Control Still Matters despite Insecticide Resistance. Trends Parasitol 2017; 33:610-618. [PMID: 28499699 DOI: 10.1016/j.pt.2017.04.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 04/14/2017] [Accepted: 04/18/2017] [Indexed: 11/26/2022]
Abstract
Mosquito vectors' resistance to insecticides is usually considered a major threat to the recent progresses in malaria control. However, studies measuring the impact of interventions and insecticide resistance reveal inconsistencies when using entomological versus epidemiological indices. First, evaluation tests that do not reflect the susceptibility of mosquitoes when they are infectious may underestimate insecticide efficacy. Moreover, interactions between insecticide resistance and vectorial capacity reveal nonintuitive outcomes of interventions. Therefore, considering ecological interactions between vector, parasite, and environment highlights that the impact of insecticide resistance on the malaria burden is not straightforward and we suggest that vector control still matters despite insecticide resistance.
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Affiliation(s)
- Haoues Alout
- Institut des Sciences de l'Evolution de Montpellier, CNRS, IRD, University of Montpellier, ISEM - UMR 5554, Montpellier, France.
| | - Pierrick Labbé
- Institut des Sciences de l'Evolution de Montpellier, CNRS, IRD, University of Montpellier, ISEM - UMR 5554, Montpellier, France
| | - Fabrice Chandre
- Institut de recherche pour le développement (IRD), Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle (MIVEGEC), UM-CNRS 5290 IRD 224, Montpellier, France
| | - Anna Cohuet
- Institut de recherche pour le développement (IRD), Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle (MIVEGEC), UM-CNRS 5290 IRD 224, Montpellier, France.
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