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Annamalai Subramani P, Tipthara P, Kolli SK, Nicholas J, Barnes SJ, Ogbondah MM, Kobylinski KC, Tarning J, Adams JH. Efficacy of ivermectin and its metabolites against Plasmodium falciparum liver stages in primary human hepatocytes. Antimicrob Agents Chemother 2024; 68:e0127223. [PMID: 38904389 PMCID: PMC11304735 DOI: 10.1128/aac.01272-23] [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: 10/03/2023] [Accepted: 06/01/2024] [Indexed: 06/22/2024] Open
Abstract
Ivermectin, a broad-spectrum anti-parasitic drug, has been proposed as a novel vector control tool to reduce malaria transmission by mass drug administration. Ivermectin and some metabolites have mosquito-lethal effect, reducing Anopheles mosquito survival. Ivermectin inhibits liver stage development in a rodent malaria model, but no inhibition was observed in a primate malaria model or in a human malaria challenge trial. In the liver, cytochrome P450 3A4 and 3A5 enzymes metabolize ivermectin, which may impact drug efficacy. Thus, understanding ivermectin metabolism and assessing this impact on Plasmodium liver stage development is critical. Using primary human hepatocytes (PHHs), we characterized ivermectin metabolism and evaluated the efficacy of ivermectin and its primary metabolites M1 (3″-O-demethyl ivermectin) and M3 (4-hydroxymethyl ivermectin) against Plasmodium falciparum liver stages. Two different modes of ivermectin exposure were evaluated: prophylactic mode (days 0-3 post-infection) and curative mode (days 3-5 post-infection). We used two different PHH donors and modes to determine the inhibitory concentration (IC50) of ivermectin, M1, M3, and the known anti-malarial drug pyrimethamine, with IC50 values ranging from 1.391 to 14.44, 9.95-23.71, 4.767-8.384, and 0.9073-5.416 µM, respectively. In our PHH model, ivermectin and metabolites M1 and M3 demonstrated inhibitory activity against P. falciparum liver stages in curative treatment mode (days 3-5) and marginal activity in prophylactic treatment mode (days 0-3). Ivermectin had improved efficacy when co-administered with ketoconazole, a specific inhibitor of cytochrome P450 3A4 enzyme. Further studies should be performed to examine ivermectin liver stage efficacy when co-administered with CYP3A4 inhibitors and anti-malarial drugs to understand the pharmacokinetic and pharmacodynamic drug-drug interactions that enhance efficacy against human malaria parasites in vitro.
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Affiliation(s)
- Pradeep Annamalai Subramani
- Center for Global Health and Interdisciplinary Research, College of Public Health, University of South Florida, Tampa, Florida, USA
| | - Phornpimon Tipthara
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Surendra Kumar Kolli
- Center for Global Health and Interdisciplinary Research, College of Public Health, University of South Florida, Tampa, Florida, USA
| | - Justin Nicholas
- Center for Global Health and Interdisciplinary Research, College of Public Health, University of South Florida, Tampa, Florida, USA
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Samantha J. Barnes
- Center for Global Health and Interdisciplinary Research, College of Public Health, University of South Florida, Tampa, Florida, USA
| | - Madison M. Ogbondah
- Center for Global Health and Interdisciplinary Research, College of Public Health, University of South Florida, Tampa, Florida, USA
| | - Kevin C. Kobylinski
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Department of Entomology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Joel Tarning
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - John H. Adams
- Center for Global Health and Interdisciplinary Research, College of Public Health, University of South Florida, Tampa, Florida, USA
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Hamid-Adiamoh M, Muhammad AK, Assogba BS, Soumare HM, Jadama L, Diallo M, D'Alessandro U, Ousmane Ndiath M, Erhart A, Amambua-Ngwa A. Mosquitocidal effect of ivermectin-treated nettings and sprayed walls on Anopheles gambiae s.s. Sci Rep 2024; 14:12620. [PMID: 38824239 PMCID: PMC11144240 DOI: 10.1038/s41598-024-63389-x] [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: 06/01/2023] [Accepted: 05/28/2024] [Indexed: 06/03/2024] Open
Abstract
Ivermectin (IVM) has been proposed as a new tool for malaria control as it is toxic on vectors feeding on treated humans or cattle. Nevertheless, IVM may have a direct mosquitocidal effect when applied on bed nets or sprayed walls. The potential for IVM application as a new insecticide for long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) was tested in this proof-of-concept study in a laboratory and semi-field environment. Laboratory-reared, insecticide-susceptible Kisumu Anopheles gambiae were exposed to IVM on impregnated netting materials and sprayed plastered- and mud walls using cone bioassays. The results showed a direct mosquitocidal effect of IVM on this mosquito strain as all mosquitoes died by 24 h after exposure to IVM. The effect was slower on the IVM-sprayed walls compared to the treated nettings. Further work to evaluate possibility of IVM as a new insecticide formulation in LLINs and IRS will be required.
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Affiliation(s)
- Majidah Hamid-Adiamoh
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, Gambia.
| | - Abdul Khalie Muhammad
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, Gambia
| | - Benoit Sessinou Assogba
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, Gambia
| | - Harouna Massire Soumare
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, Gambia
| | - Lamin Jadama
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, Gambia
| | - Moussa Diallo
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, Gambia
| | - Umberto D'Alessandro
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, Gambia
| | - Mamadou Ousmane Ndiath
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, Gambia
| | - Annette Erhart
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, Gambia
| | - Alfred Amambua-Ngwa
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Banjul, Gambia
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3
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Wangrawa DW, Odero JO, Baldini F, Okumu F, Badolo A. Distribution and insecticide resistance profile of the major malaria vector Anopheles funestus group across the African continent. MEDICAL AND VETERINARY ENTOMOLOGY 2024; 38:119-137. [PMID: 38303659 DOI: 10.1111/mve.12706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 01/10/2024] [Indexed: 02/03/2024]
Abstract
There has been significant progress in malaria control in the last 2 decades, with a decline in mortality and morbidity. However, these gains are jeopardised by insecticide resistance, which negatively impacts the core interventions, such as insecticide-treated nets (ITN) and indoor residual spraying (IRS). While most malaria control and research efforts are still focused on Anopheles gambiae complex mosquitoes, Anopheles funestus remains an important vector in many countries and, in some cases, contributes to most of the local transmission. As countries move towards malaria elimination, it is important to ensure that all dominant vector species, including An. funestus, an important vector in some countries, are targeted. The objective of this review is to compile and discuss information related to A. funestus populations' resistance to insecticides and the mechanisms involved across Africa, emphasising the sibling species and their resistance profiles in relation to malaria elimination goals. Data on insecticide resistance in An. funestus malaria vectors in Africa were extracted from published studies. Online bibliographic databases, including Google Scholar and PubMed, were used to search for relevant studies. Articles published between 2000 and May 2023 reporting resistance of An. funestus to insecticides and associated mechanisms were included. Those reporting only bionomics were excluded. Spatial variation in species distribution and resistance to insecticides was recorded from 174 articles that met the selection criteria. It was found that An. funestus was increasingly resistant to the four classes of insecticides recommended by the World Health Organisation for malaria vector control; however, this varied by country. Insecticide resistance appears to reduce the effectiveness of vector control methods, particularly IRS and ITN. Biochemical resistance due to detoxification enzymes (P450s and glutathione-S-transferases [GSTs]) in An. funestus was widely recorded. However, An. funestus in Africa remains susceptible to other insecticide classes, such as organophosphates and neonicotinoids. This review highlights the increasing insecticide resistance of An. funestus mosquitoes, which are important malaria vectors in Africa, posing a significant challenge to malaria control efforts. While An. funestus has shown resistance to the recommended insecticide classes, notably pyrethroids and, in some cases, organochlorides and carbamates, it remains susceptible to other classes of insecticides such as organophosphates and neonicotinoids, providing potential alternative options for vector control strategies. The study underscores the need for targeted interventions that consider the population structure and geographical distribution of An. funestus, including its sibling species and their insecticide resistance profiles, to effectively achieve malaria elimination goals.
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Affiliation(s)
- Dimitri W Wangrawa
- Laboratoire d'Entomologie Fondamentale et Appliquée, Université Joseph Ki-Zerbo, Ouagadougou, Burkina Faso
- Département des Sciences de la Vie et de la Terre, Université Norbert Zongo, Koudougou, Burkina Faso
| | - Joel O Odero
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
- School of Biodiversity, One Health, and Veterinary Medicine, University of Glasgow, Glasgow, UK
| | - Francesco Baldini
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
- School of Biodiversity, One Health, and Veterinary Medicine, University of Glasgow, Glasgow, UK
| | - Fredros Okumu
- Environmental Health and Ecological Sciences Department, Ifakara Health Institute, Ifakara, Tanzania
| | - Athanase Badolo
- Laboratoire d'Entomologie Fondamentale et Appliquée, Université Joseph Ki-Zerbo, Ouagadougou, Burkina Faso
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Vanachayangkul P, Kodchakorn C, Ta-Aksorn W, Im-Erbsin R, Tungtaeng A, Tipthara P, Tarning J, Lugo-Roman LA, Wojnarski M, Vesely BA, Kobylinski KC. Safety, pharmacokinetics, and potential neurological interactions of ivermectin, tafenoquine, and chloroquine in Rhesus macaques. Antimicrob Agents Chemother 2024:e0018124. [PMID: 38742896 DOI: 10.1128/aac.00181-24] [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: 02/01/2024] [Accepted: 04/19/2024] [Indexed: 05/16/2024] Open
Abstract
Ivermectin (IVM) could be used for malaria control as treated individuals are lethal to blood-feeding Anopheles, resulting in reduced transmission. Tafenoquine (TQ) is used to clear the liver reservoir of Plasmodium vivax and as a prophylactic treatment in high-risk populations. It has been suggested to use ivermectin and tafenoquine in combination, but the safety of these drugs in combination has not been evaluated. Early derivatives of 8-aminoquinolones (8-AQ) were neurotoxic, and ivermectin is an inhibitor of the P-glycoprotein (P-gp) blood brain barrier (BBB) transporter. Thus, there is concern that co-administration of these drugs could be neurotoxic. This study aimed to evaluate the safety and pharmacokinetic interaction of tafenoquine, ivermectin, and chloroquine (CQ) in Rhesus macaques. No clinical, biochemistry, or hematological outcomes of concern were observed. The Cambridge Neuropsychological Test Automated Battery (CANTAB) was employed to assess potential neurological deficits following drug administration. Some impairment was observed with tafenoquine alone and in the same monkeys with subsequent co-administrations. Co-administration of chloroquine and tafenoquine resulted in increased plasma exposure to tafenoquine. Urine concentrations of the 5,6 orthoquinone TQ metabolite were increased with co-administration of tafenoquine and ivermectin. There was an increase in ivermectin plasma exposure when co-administered with chloroquine. No interaction of tafenoquine on ivermectin was observed in vitro. Chloroquine and trace levels of ivermectin, but not tafenoquine, were observed in the cerebrospinal fluid. The 3''-O-demethyl ivermectin metabolite was observed in macaque plasma but not in urine or cerebrospinal fluid. Overall, the combination of ivermectin, tafenoquine, and chloroquine did not have clinical, neurological, or pharmacological interactions of concern in macaques; therefore, this combination could be considered for evaluation in human trials.
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Affiliation(s)
- Pattaraporn Vanachayangkul
- Department of Bacterial and Parasitic Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Chanikarn Kodchakorn
- Department of Bacterial and Parasitic Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Winita Ta-Aksorn
- Department of Bacterial and Parasitic Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Rawiwan Im-Erbsin
- Department of Veterinary Medicine, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Anchalee Tungtaeng
- Department of Veterinary Medicine, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Phornpimon Tipthara
- Mahidol Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
| | - Joel Tarning
- Mahidol Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - Luis A Lugo-Roman
- Department of Veterinary Medicine, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Mariusz Wojnarski
- Department of Bacterial and Parasitic Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Brian A Vesely
- Department of Bacterial and Parasitic Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Kevin C Kobylinski
- Mahidol Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
- Department of Entomology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
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Ekoka Mbassi D, Mombo-Ngoma G, Held J, Okwu DG, Ndzebe-Ndoumba W, Kalkman LC, Ekoka Mbassi FA, Pessanha de Carvalho L, Inoue J, Akinosho MA, Dimessa Mbadinga LB, Yovo EK, Mordmüller B, Kremsner PG, Adegnika AA, Ramharter M, Zoleko-Manego R. Efficacy and safety of ivermectin for the treatment of Plasmodium falciparum infections in asymptomatic male and female Gabonese adults - a pilot randomized, double-blind, placebo-controlled single-centre phase Ib/IIa clinical trial. EBioMedicine 2023; 97:104814. [PMID: 37839134 PMCID: PMC10582777 DOI: 10.1016/j.ebiom.2023.104814] [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: 03/31/2023] [Revised: 08/21/2023] [Accepted: 09/15/2023] [Indexed: 10/17/2023] Open
Abstract
BACKGROUND Ivermectin's mosquitocidal effect and in vitro activity against Plasmodium falciparum asexual stages are known. Its in vivo blood-schizonticidal efficacy is unknown. Ivermectin's tolerability and efficacy against P. falciparum infections in Gabonese adults were assessed. METHODS The study consisted of a multiple dose stage and a randomized, double-blind, placebo-controlled stage. Adults with asymptomatic P. falciparum parasitaemia (200-5000 parasites/μl) were enrolled. First, three groups of five participants received 200 μg/kg ivermectin once daily for one, two, and three days, respectively, and then 34 participants were randomized to 300 μg/kg ivermectin or placebo once daily for 3 days. Primary efficacy outcome was time to 90% parasite reduction. Primary safety outcomes were drug-related serious and severe adverse events (Trial registration: PACTR201908520097051). FINDINGS Between June 2019 and October 2020, 49 participants were enrolled. Out of the 34 randomized participants, 29 (85%) completed the trial as per protocol. No severe or serious adverse events were observed. The median time to 90% parasite reduction was 24.1 vs. 32.0 h in the ivermectin and placebo groups, respectively (HR 1.38 [95% CI 0.64 to 2.97]). INTERPRETATION Ivermectin was well tolerated in doses up to 300 μg/kg once daily for three days and asymptomatic P. falciparum asexual parasitaemia was reduced similarly with this dose of ivermectin compared to placebo. Further studies are needed to evaluate plasmodicidal effect of ivermectin at higher doses and in larger samples. FUNDING This study was funded by the Centre de Recherches Médicales de Lambaréné and the Centre for Tropical Medicine of the Bernhard Nocht Institute for Tropical Medicine.
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Affiliation(s)
- Dorothea Ekoka Mbassi
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon; Centre for Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; German Center for Infection Research (DZIF), Partner Site Hamburg-Borstel-Lübeck-Riems, Germany
| | - Ghyslain Mombo-Ngoma
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon; German Center for Infection Research (DZIF), Partner Site Hamburg-Borstel-Lübeck-Riems, Germany; Department of Implementation Research, Bernhard Nocht Institute for Tropical Medicine & I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Jana Held
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany; German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany
| | - Dearie Glory Okwu
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon; Department of Implementation Research, Bernhard Nocht Institute for Tropical Medicine & I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Wilfrid Ndzebe-Ndoumba
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon; Department of Implementation Research, Bernhard Nocht Institute for Tropical Medicine & I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | | | - Franck Aurelien Ekoka Mbassi
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon; Centre for Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; German Center for Infection Research (DZIF), Partner Site Hamburg-Borstel-Lübeck-Riems, Germany
| | | | - Juliana Inoue
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | | | | | | | - Benjamin Mordmüller
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany; Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, the Netherlands
| | - Peter Gottfried Kremsner
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon; Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany; German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany
| | - Ayôla Akim Adegnika
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon; Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany; German Center for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany; Department of Parasitology, Leiden University Medical Centre (LUMC), 2333 ZA, Leiden, the Netherlands; Fondation pour la Recherche Scientifique, 72 BP45, Cotonou, Benin
| | - Michael Ramharter
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon; Centre for Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; German Center for Infection Research (DZIF), Partner Site Hamburg-Borstel-Lübeck-Riems, Germany
| | - Rella Zoleko-Manego
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon; Centre for Tropical Medicine, Bernhard Nocht Institute for Tropical Medicine & I. Department of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; German Center for Infection Research (DZIF), Partner Site Hamburg-Borstel-Lübeck-Riems, Germany; Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.
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Failoc-Rojas VE, Silva-Díaz H, Maguiña JL, Rodriguez-Morales AJ, Díaz-Velez C, Apolaya-Segura M, Valladares-Garrido MJ. Evidence-based indications for ivermectin in parasitic diseases: An integrated approach to context and challenges in Peru. Parasite Epidemiol Control 2023; 23:e00320. [PMID: 37731824 PMCID: PMC10507222 DOI: 10.1016/j.parepi.2023.e00320] [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: 01/12/2023] [Revised: 06/07/2023] [Accepted: 07/29/2023] [Indexed: 09/22/2023] Open
Abstract
Ivermectin has emerged as a therapeutic option for various parasitic diseases, including strongyloidiasis, scabies, lice infestations, gnathostomiasis, and myiasis. This study comprehensively reviews the evidence-based indications for ivermectin in treating parasitic diseases, considering the unique context and challenges in Peru. Fourteen studies were selected from a systematic search of scientific evidence on ivermectin in PubMed, from 2010 to July 2022. The optimal dosage of ivermectin for treating onchocerciasis, strongyloidiasis, and enterobiasis ranges from 150 to 200 μg/kg, while lymphatic filariasis requires a higher dose of 400 μg/kg (Brown et al., 2000). However, increased dosages have been associated with a higher incidence of ocular adverse events. Scientific evidence shows that ivermectin can be safely and effectively administered to children weighing less than 15 kg. Systematic reviews and meta-analyses provide strong support for the efficacy and safety of ivermectin in combating parasitic infections. Ivermectin has proven to be an effective treatment for various parasitic diseases, including intestinal parasites, ectoparasites, filariasis, and onchocerciasis. Dosages ranging from 200 μg/kg to 400 μg/kg are generally safe, with adjustments made according to the specific pathology, patient age, and weight/height. Given Peru's prevailing social and environmental conditions, the high burden of intestinal parasites and ectoparasites in the country underscores the importance of ivermectin in addressing these health challenges.
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Affiliation(s)
- Virgilio E. Failoc-Rojas
- Instituto de Evaluación de Tecnologías en Salud e Investigación, EsSalud, Lima, Peru
- Universidad San Ignacio de Loyola, Lima, Peru
| | - Heber Silva-Díaz
- Facultad de Medicina Huamana, Universidad de San Martín de Porres, Chiclayo, Peru
| | - Jorge L. Maguiña
- Instituto de Evaluación de Tecnologías en Salud e Investigación, EsSalud, Lima, Peru
- School of Medicine, Universidad Científica del Sur, Lima, Peru
| | - Alfonso J. Rodriguez-Morales
- Grupo de Investigación Biomedicina, Faculty of Medicine, Fundacion Universitaria Autónoma de las Américas, Pereira, Colombia
- Gilbert and Rose-Marie Chagoury School of Medicine, Lebanese American University, Beirut 1102, Lebanon
| | - Cristian Díaz-Velez
- Facultad de Medicina, Universidad Privada Antenor Orrego, Trujillo, Peru
- Instituto Nacional Cardiovascular, INCOR, EsSalud, Lima, Peru
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7
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Sagna AB, Zéla L, Ouedraogo COW, Pooda SH, Porciani A, Furnival-Adams J, Lado P, Somé AF, Pennetier C, Chaccour CJ, Dabiré RK, Mouline K. Ivermectin as a novel malaria control tool: Getting ahead of the resistance curse. Acta Trop 2023; 245:106973. [PMID: 37352998 DOI: 10.1016/j.actatropica.2023.106973] [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] [Revised: 06/14/2023] [Accepted: 06/16/2023] [Indexed: 06/25/2023]
Abstract
Reduction in malaria clinical cases is strongly dependent on the ability to prevent Anopheles infectious bites. Vector control strategies using long-lasting insecticidal nets and indoor residual spraying with insecticides have contributed to significantly reduce the incidence of malaria in many endemic countries, especially in the Sub-Saharan region. However, global progress in reducing malaria cases has plateaued since 2015 mostly due to the increased insecticide resistance and behavioral changes in Anopheles vectors. Additional control strategies are thus required to further reduce the burden of malaria and contain the spread of resistant and invasive Anopheles vectors. The use of endectocides such as ivermectin as an additional malaria control tool is now receiving increased attention, driven by its different mode of action compared to insecticides used so far and its excellent safety record for humans. In this opinion article, we discuss the advantages and disadvantages of using ivermectin for malaria control with a focus on the risk of selecting ivermectin resistance in malaria vectors. We also highlight the importance of understanding how ivermectin resistance could develop in mosquitoes and what its underlying mechanisms and associated molecular markers are, and propose a research agenda to manage this phenomenon.
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Affiliation(s)
- André B Sagna
- MIVEGEC, University of Montpellier, IRD, CNRS, Montpellier, France.
| | - Lamidi Zéla
- Centre International de Recherche-Développement sur l'Elevage en zone Subhumide, Bobo-Dioulasso, Burkina Faso
| | - Cheick Oumar W Ouedraogo
- Institut de Recherche en Sciences de la Santé, Direction Régionale de l'Ouest, Centre National de Recherche Scientifique et Technologique, Bobo-Dioulasso, Burkina Faso
| | - Sié H Pooda
- Centre International de Recherche-Développement sur l'Elevage en zone Subhumide, Bobo-Dioulasso, Burkina Faso; Université de Dédougou, Dédougou, Burkina Faso
| | | | | | - Paula Lado
- Center for Vector-borne Infectious Diseases, Colorado State University, Fort Collins, CO, USA
| | - Anyirékun F Somé
- Institut de Recherche en Sciences de la Santé, Direction Régionale de l'Ouest, Centre National de Recherche Scientifique et Technologique, Bobo-Dioulasso, Burkina Faso
| | - Cédric Pennetier
- MIVEGEC, University of Montpellier, IRD, CNRS, Montpellier, France
| | - Carlos J Chaccour
- ISGlobal, Barcelona Institute for Global Health, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Infecciosas, Madrid, Spain; Universidad de Navarra, Pamplona, Spain
| | - Roch K Dabiré
- Institut de Recherche en Sciences de la Santé, Direction Régionale de l'Ouest, Centre National de Recherche Scientifique et Technologique, Bobo-Dioulasso, Burkina Faso
| | - Karine Mouline
- MIVEGEC, University of Montpellier, IRD, CNRS, Montpellier, France
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8
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Kiuru C, Ominde K, Muturi M, Babu L, Wanjiku C, Chaccour C, Maia MF. Effects of larval exposure to sublethal doses of ivermectin on adult fitness and susceptibility to ivermectin in Anopheles gambiae s.s. Parasit Vectors 2023; 16:293. [PMID: 37605264 PMCID: PMC10441747 DOI: 10.1186/s13071-023-05888-w] [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: 03/01/2023] [Accepted: 07/18/2023] [Indexed: 08/23/2023] Open
Abstract
BACKGROUND The effects of ivermectin (endectocide) on mosquito survival make it a potential new malaria vector control tool. The drug can be administered to mosquito disease vectors through blood hosts that include humans and livestock. Its increased use may cause contamination of larval habitats, either directly through livestock excreta or indirectly through leaching or run-off from contaminated soil, albeit in sublethal doses. However, the effects of such exposure on immature stages and the subsequent adults that emerge are poorly understood. This study was undertaken to evaluate the impact of ivermectin exposure on Anopheles gambiae s.s. larvae and its effects on fitness and susceptibility to ivermectin in the emerging adults. METHODS Laboratory-reared An. gambiae s.s. (Kilifi strain) larvae were exposed to five different ivermectin concentrations; 0, 0.00001, 0.0001, 0.001, and 0.01 ppm, and larval survival was monitored to determine the appropriate sub-lethal dose. Concentrations with survival > 50% (0.00001 and 0.0001 ppm) were selected and used as the sub-lethal doses. The fecundity, fertility, and susceptibility to ivermectin of adults emerging after larval exposure to the sub-lethal doses were examined. RESULTS Overall, exposure of An. gambiae s.s. aquatic stages to ivermectin caused a dose-dependent reduction in larval survival irrespective of the stage at which the larvae were exposed. Exposure to ivermectin in the larval stage did not have an effect on either the number of eggs laid or the hatch rate. However, exposure of first/second-instar larvae to 0.0001 ppm and third/fourth-instar larvae to 0.001 ppm of ivermectin reduced the time taken to oviposition. Additionally, exposure to ivermectin in the larval stage did not affect susceptibility of the emerging adults to the drug. CONCLUSIONS This study shows that contamination of larval habitats with ivermectin affects An. gambiae s.s. larval survival and could potentially have an impact on public health. However, there are no carry-over effects on the fecundity, fertility, and susceptibility of the emerging adults to ivermectin. In addition, this study shows that environmental exposure to ivermectin in the larval habitats is unlikely to compromise the efficacy of ivermectin in the emerging adults.
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Affiliation(s)
- Caroline Kiuru
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic - Universitat de Barcelona, Rosello 132, 5ª 2ª, 08036, Barcelona, Spain.
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique.
| | - Kelly Ominde
- Department of Biosciences, KEMRI Wellcome Trust Research Programme (KWTRP), Kilifi, 230-80108, Kenya
- Pwani University, Department of Biological Sciences and Pwani University Bioscience Research Centre (PUBReC), Kilifi, Kenya
| | - Martha Muturi
- Department of Biosciences, KEMRI Wellcome Trust Research Programme (KWTRP), Kilifi, 230-80108, Kenya
| | - Lawrence Babu
- Department of Biosciences, KEMRI Wellcome Trust Research Programme (KWTRP), Kilifi, 230-80108, Kenya
| | - Caroline Wanjiku
- Department of Biosciences, KEMRI Wellcome Trust Research Programme (KWTRP), Kilifi, 230-80108, Kenya
| | - Carlos Chaccour
- Barcelona Institute for Global Health (ISGlobal), Hospital Clínic - Universitat de Barcelona, Rosello 132, 5ª 2ª, 08036, Barcelona, Spain
- Facultad de Medicina, Universidad de Navarra, 31008, Pamplona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas, Madrid, Spain
| | - Marta Ferreira Maia
- Department of Biosciences, KEMRI Wellcome Trust Research Programme (KWTRP), Kilifi, 230-80108, Kenya.
- Nuffield Department of Medicine, Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK.
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9
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Yipsirimetee A, Tipthara P, Hanboonkunupakarn B, Tripura R, Lek D, Kümpornsin K, Lee MCS, Sattabongkot J, Dondorp AM, White NJ, Kobylinski KC, Tarning J, Chotivanich K. Activity of Ivermectin and Its Metabolites against Asexual Blood Stage Plasmodium falciparum and Its Interactions with Antimalarial Drugs. Antimicrob Agents Chemother 2023; 67:e0173022. [PMID: 37338381 PMCID: PMC10368210 DOI: 10.1128/aac.01730-22] [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: 12/29/2022] [Accepted: 05/12/2023] [Indexed: 06/21/2023] Open
Abstract
Ivermectin is an endectocide used widely to treat a variety of internal and external parasites. Field trials of ivermectin mass drug administration for malaria transmission control have demonstrated a reduction of Anopheles mosquito survival and human malaria incidence. Ivermectin will mostly be deployed together with artemisinin-based combination therapies (ACT), the first-line treatment of falciparum malaria. It has not been well established if ivermectin has activity against asexual stage Plasmodium falciparum or if it interacts with the parasiticidal activity of other antimalarial drugs. This study evaluated antimalarial activity of ivermectin and its metabolites in artemisinin-sensitive and artemisinin-resistant P. falciparum isolates and assessed in vitro drug-drug interaction with artemisinins and its partner drugs. The concentration of ivermectin causing half of the maximum inhibitory activity (IC50) on parasite survival was 0.81 μM with no significant difference between artemisinin-sensitive and artemisinin-resistant isolates (P = 0.574). The ivermectin metabolites were 2-fold to 4-fold less active than the ivermectin parent compound (P < 0.001). Potential pharmacodynamic drug-drug interactions of ivermectin with artemisinins, ACT-partner drugs, and atovaquone were studied in vitro using mixture assays providing isobolograms and derived fractional inhibitory concentrations. There were no synergistic or antagonistic pharmacodynamic interactions when combining ivermectin and antimalarial drugs. In conclusion, ivermectin does not have clinically relevant activity against the asexual blood stages of P. falciparum. It also does not affect the in vitro antimalarial activity of artemisinins or ACT-partner drugs against asexual blood stages of P. falciparum.
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Affiliation(s)
- Achaporn Yipsirimetee
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Phornpimon Tipthara
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Borimas Hanboonkunupakarn
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Rupam Tripura
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Dysoley Lek
- National Center for Parasitology, Entomology and Malaria Control, Phnom Penh, Cambodia
| | - Krittikorn Kümpornsin
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom
- Calibr, Division of the Scripps Research Institute, La Jolla, California, USA
| | - Marcus C. S. Lee
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom
| | - Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Arjen M. Dondorp
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Nicholas J. White
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Kevin C. Kobylinski
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Department of Entomology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Joel Tarning
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Kesinee Chotivanich
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Mahidol Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
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10
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Hutchins H, Bradley J, Pretorius E, Teixeira da Silva E, Vasileva H, Jones RT, Ndiath MO, Dit Massire Soumare H, Mabey D, Nante EJ, Martins C, Logan JG, Slater H, Drakeley C, D'Alessandro U, Rodrigues A, Last AR. Protocol for a cluster randomised placebo-controlled trial of adjunctive ivermectin mass drug administration for malaria control on the Bijagós Archipelago of Guinea-Bissau: the MATAMAL trial. BMJ Open 2023; 13:e072347. [PMID: 37419638 PMCID: PMC10335573 DOI: 10.1136/bmjopen-2023-072347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 06/20/2023] [Indexed: 07/09/2023] Open
Abstract
INTRODUCTION As malaria declines, innovative tools are required to further reduce transmission and achieve elimination. Mass drug administration (MDA) of artemisinin-based combination therapy (ACT) is capable of reducing malaria transmission where coverage of control interventions is already high, though the impact is short-lived. Combining ACT with ivermectin, an oral endectocide shown to reduce vector survival, may increase its impact, while also treating ivermectin-sensitive co-endemic diseases and minimising the potential impact of ACT resistance in this context. METHODS AND ANALYSIS MATAMAL is a cluster-randomised placebo-controlled trial. The trial is being conducted in 24 clusters on the Bijagós Archipelago, Guinea-Bissau, where the peak prevalence of Plasmodium falciparum (Pf) parasitaemia is approximately 15%. Clusters have been randomly allocated to receive MDA with dihydroartemisinin-piperaquine and either ivermectin or placebo. The primary objective is to determine whether the addition of ivermectin MDA is more effective than dihydroartemisinin-piperaquine MDA alone in reducing the prevalence of P. falciparum parasitaemia, measured during peak transmission season after 2 years of seasonal MDA. Secondary objectives include assessing prevalence after 1 year of MDA; malaria incidence monitored through active and passive surveillance; age-adjusted prevalence of serological markers indicating exposure to P. falciparum and anopheline mosquitoes; vector parous rates, species composition, population density and sporozoite rates; prevalence of vector pyrethroid resistance; prevalence of artemisinin resistance in P. falciparum using genomic markers; ivermectin's impact on co-endemic diseases; coverage estimates; and the safety of combined MDA. ETHICS AND DISSEMINATION The trial has been approved by the London School of Hygiene and Tropical Medicine's Ethics Committee (UK) (19156) and the Comite Nacional de Eticas de Saude (Guinea-Bissau) (084/CNES/INASA/2020). Results will be disseminated in peer-reviewed publications and in discussion with the Bissau-Guinean Ministry of Public Health and participating communities. TRIAL REGISTRATION NUMBER NCT04844905.
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Affiliation(s)
- Harry Hutchins
- Clinical Research Department, London School of Hygiene and Tropical Medicine, London, UK
| | - John Bradley
- Clinical Research Department, London School of Hygiene and Tropical Medicine, London, UK
| | - Elizabeth Pretorius
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | - Eunice Teixeira da Silva
- Projecto de Saúde Bandim, Bissau, Guinea-Bissau
- Ministério de Saúde Pública, Bissau, Guinea-Bissau
| | - Hristina Vasileva
- Clinical Research Department, London School of Hygiene and Tropical Medicine, London, UK
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
| | - Robert T Jones
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | | | | | - David Mabey
- Clinical Research Department, London School of Hygiene and Tropical Medicine, London, UK
| | - Ernesto Jose Nante
- Programa Nacional de Luta Contra o Paludismo, Ministério de Saúde, Bissau, Guinea-Bissau
| | | | - James G Logan
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
- Arctech Innovation, London, UK
| | | | - Chris Drakeley
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, UK
| | | | - Amabelia Rodrigues
- Projecto de Saúde Bandim, Bissau, Guinea-Bissau
- Ministério de Saúde Pública, Bissau, Guinea-Bissau
| | - Anna R Last
- Clinical Research Department, London School of Hygiene and Tropical Medicine, London, UK
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11
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Kern C, Müller P, Chaccour C, Liechti ME, Hammann F, Duthaler U. Pharmacokinetics of ivermectin metabolites and their activity against Anopheles stephensi mosquitoes. Malar J 2023; 22:194. [PMID: 37355605 DOI: 10.1186/s12936-023-04624-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Accepted: 06/16/2023] [Indexed: 06/26/2023] Open
Abstract
BACKGROUND Ivermectin (22,23-dihydroavermectin B1a: H2B1a) is an endectocide used to treat worm infections and ectoparasites including lice and scabies mites. Furthermore, survival of malaria transmitting Anopheles mosquitoes is strongly decreased after feeding on humans recently treated with ivermectin. Currently, mass drug administration of ivermectin is under investigation as a potential novel malaria vector control tool to reduce Plasmodium transmission by mosquitoes. A "post-ivermectin effect" has also been reported, in which the survival of mosquitoes remains reduced even after ivermectin is no longer detectable in blood meals. In the present study, existing material from human clinical trials was analysed to understand the pharmacokinetics of ivermectin metabolites and feeding experiments were performed in Anopheles stephensi mosquitoes to assess whether ivermectin metabolites contribute to the mosquitocidal action of ivermectin and whether they may be responsible for the post-ivermectin effect. METHODS Ivermectin was incubated in the presence of recombinant human cytochrome P450 3A4/5 (CYP 3A4/5) to produce ivermectin metabolites. In total, nine metabolites were purified by semi-preparative high-pressure liquid chromatography. The pharmacokinetics of the metabolites were assessed over three days in twelve healthy volunteers who received a single oral dose of 12 mg ivermectin. Blank whole blood was spiked with the isolated metabolites at levels matching the maximal blood concentration (Cmax) observed in pharmacokinetics study samples. These samples were fed to An. stephensi mosquitoes, and their survival and vitality was recorded daily over 3 days. RESULTS Human CYP3A4 metabolised ivermectin more rapidly than CYP3A5. Ivermectin metabolites M1-M8 were predominantly formed by CYP3A4, whereas metabolite M9 (hydroxy-H2B1a) was mainly produced by CYP3A5. Both desmethyl-H2B1a (M1) and hydroxy-H2B1a (M2) killed all mosquitoes within three days post-feeding, while administration of desmethyl, hydroxy-H2B1a (M4) reduced survival to 35% over an observation period of 3 days. Ivermectin metabolites that underwent deglycosylation or hydroxylation at spiroketal moiety were not active against An. stephensi at Cmax levels. Interestingly, half-lives of M1 (54.2 ± 4.7 h) and M4 (57.5 ± 13.2 h) were considerably longer than that of the parent compound ivermectin (38.9 ± 20.8 h). CONCLUSION In conclusion, the ivermectin metabolites M1 and M2 contribute to the activity of ivermectin against An. stephensi mosquitoes and could be responsible for the "post-ivermectin effect".
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Affiliation(s)
- Charlotte Kern
- Division of Clinical Pharmacology & Toxicology, Department of Internal Medicine, University Hospital Bern, Bern, Switzerland
- Graduate School for Health Sciences, University of Bern, Bern, Switzerland
| | - Pie Müller
- Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Carlos Chaccour
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas, Madrid, Spain
- Facultad de Medicina, Universidad de Navarra, Pamplona, Spain
| | - Matthias E Liechti
- Division of Clinical Pharmacology & Toxicology, Department of Biomedicine, University and University Hospital Basel, Basel, Switzerland
- Division of Clinical Pharmacology & Toxicology, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland
| | - Felix Hammann
- Division of Clinical Pharmacology & Toxicology, Department of Internal Medicine, University Hospital Bern, Bern, Switzerland
| | - Urs Duthaler
- Division of Clinical Pharmacology & Toxicology, Department of Biomedicine, University and University Hospital Basel, Basel, Switzerland.
- Division of Clinical Pharmacology & Toxicology, Department of Pharmaceutical Sciences, University of Basel, Basel, Switzerland.
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12
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Foy BD, Some A, Magalhaes T, Gray L, Rao S, Sougue E, Jackson CL, Kittelson J, Slater HC, Bousema T, Da O, Coulidiaty AGV, Colt M, Wade M, Richards K, Some AF, Dabire RK, Parikh S. Repeat Ivermectin Mass Drug Administrations for Malaria Control II: Protocol for a Double-blind, Cluster-Randomized, Placebo-Controlled Trial for the Integrated Control of Malaria. JMIR Res Protoc 2023; 12:e41197. [PMID: 36939832 PMCID: PMC10132043 DOI: 10.2196/41197] [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: 07/19/2022] [Revised: 01/31/2023] [Accepted: 01/31/2023] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND The gains made against malaria have stagnated since 2015, threatened further by increasing resistance to insecticides and antimalarials. Improvement in malaria control necessitates a multipronged strategy, which includes the development of novel tools. One such tool is mass drug administration (MDA) with endectocides, primarily ivermectin, which has shown promise in reducing malaria transmission through lethal and sublethal impacts on the mosquito vector. OBJECTIVE The primary objective of the study is to assess the impact of repeated ivermectin MDA on malaria incidence in children aged ≤10 years. METHODS Repeat Ivermectin MDA for Malaria Control II is a double-blind, placebo-controlled, cluster-randomized, and parallel-group trial conducted in a setting with intense seasonal malaria transmission in Southwest Burkina Faso. The study included 14 discrete villages: 7 (50%) randomized to receive standard measures (seasonal malaria chemoprevention [SMC] and bed net use for children aged 3 to 59 months) and placebo, and 7 (50%) randomized to receive standard measures and monthly ivermectin MDA at 300 μg/kg for 3 consecutive days, provided under supervision to all eligible village inhabitants, over 2 successive rainy seasons. Nonpregnant individuals >90 cm in height were eligible for ivermectin MDA, and cotreatment with ivermectin and SMC was not permitted. The primary outcome is malaria incidence in children aged ≤10 years, as assessed by active case surveillance. The secondary safety outcome of repeated ivermectin MDA was assessed through active and passive adverse event monitoring. RESULTS The trial intervention was conducted from July to November in 2019 and 2020, with additional sampling of humans and mosquitoes occurring through February 2022 to assess postintervention changes in transmission patterns. Additional human and entomological assessments were performed over the 2 years in a subset of households from 6 cross-sectional villages. A subset of individuals underwent additional sampling in 2020 to characterize ivermectin pharmacokinetics and pharmacodynamics. Analysis and unblinding will commence once the database has been completed, cleaned, and locked. CONCLUSIONS Our trial represents the first study to directly assess the impact of a novel approach for malaria control, ivermectin MDA as a mosquitocidal agent, layered into existing standard-of-care interventions. The study was designed to leverage the current SMC deployment infrastructure and will provide evidence regarding the additional benefit of ivermectin MDA in reducing malaria incidence in children. TRIAL REGISTRATIONS ClinicalTrials.gov NCT03967054; https://clinicaltrials.gov/ct2/show/NCT03967054 and Pan African Clinical Trials Registry PACT201907479787308; https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=8219. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID) DERR1-10.2196/41197.
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Affiliation(s)
- Brian D Foy
- Center for Vector-Borne Infectious Diseases, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States
| | - Anthony Some
- Institut de Recherche en Sciences de la Santé, Direction Régionale de l'Ouest, Bobo-Dioulasso, Burkina Faso
| | - Tereza Magalhaes
- Department of Entomology, Texas A&M University, College Station, TX, United States
- Department of Preventive and Social Medicine, School of Medicine, Universidade Federal da Bahia, Salvador, Brazil
| | - Lyndsey Gray
- Center for Vector-Borne Infectious Diseases, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States
| | - Sangeeta Rao
- Department of Clinical Sciences, Colorado State University, Fort Collins, CO, United States
| | - Emmanuel Sougue
- Institut de Recherche en Sciences de la Santé, Direction Régionale de l'Ouest, Bobo-Dioulasso, Burkina Faso
| | - Conner L Jackson
- Department of Biostatistics and Informatics, University of Colorado School of Public Health, Aurora, CO, United States
| | - John Kittelson
- Department of Biostatistics and Informatics, University of Colorado School of Public Health, Aurora, CO, United States
| | - Hannah C Slater
- Malaria and Neglected Tropical Diseases, Program for Appropriate Technology in Health, Seattle, WA, United States
| | - Teun Bousema
- Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Ollo Da
- Institut de Recherche en Sciences de la Santé, Direction Régionale de l'Ouest, Bobo-Dioulasso, Burkina Faso
| | - A Gafar V Coulidiaty
- Institut de Recherche en Sciences de la Santé, Direction Régionale de l'Ouest, Bobo-Dioulasso, Burkina Faso
| | - McKenzie Colt
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, United States
| | - Martina Wade
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, United States
| | - Kacey Richards
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, United States
| | - A Fabrice Some
- Institut de Recherche en Sciences de la Santé, Direction Régionale de l'Ouest, Bobo-Dioulasso, Burkina Faso
| | - Roch K Dabire
- Institut de Recherche en Sciences de la Santé, Direction Régionale de l'Ouest, Bobo-Dioulasso, Burkina Faso
| | - Sunil Parikh
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, United States
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13
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Chaccour C, Casellas A, Hammann F, Ruiz-Castillo P, Nicolas P, Montaña J, Mael M, Selvaraj P, Duthaler U, Mrema S, Kakolwa M, Lyimo I, Okumu F, Marathe A, Schürch R, Elobolobo E, Sacoor C, Saute F, Xia K, Jones C, Rist C, Maia M, Rabinovich NR. BOHEMIA: Broad One Health Endectocide-based Malaria Intervention in Africa-a phase III cluster-randomized, open-label, clinical trial to study the safety and efficacy of ivermectin mass drug administration to reduce malaria transmission in two African settings. Trials 2023; 24:128. [PMID: 36810194 PMCID: PMC9942013 DOI: 10.1186/s13063-023-07098-2] [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: 11/19/2022] [Accepted: 01/17/2023] [Indexed: 02/23/2023] Open
Abstract
BACKGROUND Residual malaria transmission is the result of adaptive mosquito behavior that allows malaria vectors to thrive and sustain transmission in the presence of good access to bed nets or insecticide residual spraying. These behaviors include crepuscular and outdoor feeding as well as intermittent feeding upon livestock. Ivermectin is a broadly used antiparasitic drug that kills mosquitoes feeding on a treated subject for a dose-dependent period. Mass drug administration with ivermectin has been proposed as a complementary strategy to reduce malaria transmission. METHODS A cluster randomized, parallel arm, superiority trial conducted in two settings with distinct eco-epidemiological conditions in East and Southern Africa. There will be three groups: human intervention, consisting of a dose of ivermectin (400 mcg/kg) administered monthly for 3 months to all the eligible population in the cluster (>15 kg, non-pregnant and no medical contraindication); human and livestock intervention, consisting human treatment as above plus treatment of livestock in the area with a single dose of injectable ivermectin (200 mcg/kg) monthly for 3 months; and controls, consisting of a dose of albendazole (400 mg) monthly for 3 months. The main outcome measure will be malaria incidence in a cohort of children under five living in the core of each cluster followed prospectively with monthly RDTs DISCUSSION: The second site for the implementation of this protocol has changed from Tanzania to Kenya. This summary presents the Mozambique-specific protocol while the updated master protocol and the adapted Kenya-specific protocol undergo national approval in Kenya. BOHEMIA will be the first large-scale trial evaluating the impact of ivermectin-only mass drug administration to humans or humans and cattle on local malaria transmission TRIAL REGISTRATION: ClinicalTrials.gov NCT04966702 . Registered on July 19, 2021. Pan African Clinical Trials Registry PACTR202106695877303.
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Affiliation(s)
- Carlos Chaccour
- ISGlobal, Barcelona Institute for Global Health, Barcelona, Spain
- Universidda de Navarra, Pamplona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas, Madrid, Spain
| | - Aina Casellas
- ISGlobal, Barcelona Institute for Global Health, Barcelona, Spain
| | - Felix Hammann
- University Hospital of Bern, Inselspital, Bern, Switzerland
| | | | - Patricia Nicolas
- ISGlobal, Barcelona Institute for Global Health, Barcelona, Spain
| | - Julia Montaña
- ISGlobal, Barcelona Institute for Global Health, Barcelona, Spain
| | - Mary Mael
- ISGlobal, Barcelona Institute for Global Health, Barcelona, Spain
| | | | | | | | | | - Issa Lyimo
- Ifakara Health Institute, Ifakara, Tanzania
| | | | | | - Roger Schürch
- Virginia Polytechnic Institute and State University, Blacksburg, USA
| | - Eldo Elobolobo
- Centro de Investigação em Saúde de Manhiça, Manhica, Mozambique
| | | | - Francisco Saute
- Centro de Investigação em Saúde de Manhiça, Manhica, Mozambique
| | - Kang Xia
- Virginia Polytechnic Institute and State University, Blacksburg, USA
| | | | - Cassidy Rist
- Virginia Polytechnic Institute and State University, Blacksburg, USA
| | - Marta Maia
- KEMRI Wellcome Trust Research Programme, Kilifi, Kenya
| | - N. Regina Rabinovich
- ISGlobal, Barcelona Institute for Global Health, Barcelona, Spain
- TH Chan Harvard School of Public Health, Boston, USA
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14
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Pooda SH, Moiroux N, Porciani A, Courjaud AL, Roberge C, Gaudriault G, Sidibé I, Belem AMG, Rayaissé JB, Dabiré RK, Mouline K. Proof-of-concept study for a long-acting formulation of ivermectin injected in cattle as a complementary malaria vector control tool. Parasit Vectors 2023; 16:66. [PMID: 36788608 PMCID: PMC9926456 DOI: 10.1186/s13071-022-05621-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 12/15/2022] [Indexed: 02/16/2023] Open
Abstract
BACKGROUND Domesticated animals play a role in maintaining residual transmission of Plasmodium parasites of humans, by offering alternative blood meal sources for malaria vectors to survive on. However, the blood of animals treated with veterinary formulations of the anti-helminthic drug ivermectin can have an insecticidal effect on adult malaria vector mosquitoes. This study therefore assessed the effects of treating cattle with long-acting injectable formulations of ivermectin on the survival of an important malaria vector species, to determine whether it has potential as a complementary vector control measure. METHODS Eight head of a local breed of cattle were randomly assigned to either one of two treatment arms (2 × 2 cattle injected with one of two long-acting formulations of ivermectin with the BEPO® technology at the therapeutic dose of 1.2 mg/kg), or one of two control arms (2 × 2 cattle injected with the vehicles of the formulations). The lethality of the formulations was evaluated on 3-5-day-old Anopheles coluzzii mosquitoes through direct skin-feeding assays, from 1 to 210 days after treatment. The efficacy of each formulation was evaluated and compared using Cox proportional hazards survival models, Kaplan-Meier survival estimates, and log-logistic regression on cumulative mortality. RESULTS Both formulations released mosquitocidal concentrations of ivermectin until 210 days post-treatment (hazard ratio > 1). The treatments significantly reduced mosquito survival, with average median survival time of 4-5 days post-feeding. The lethal concentrations to kill 50% of the Anopheles (LC50) before they became infectious (10 days after an infectious blood meal) were maintained for 210 days post-injection for both formulations. CONCLUSIONS This long-lasting formulation of ivermectin injected in cattle could complement insecticide-treated nets by suppressing field populations of zoophagic mosquitoes that are responsible, at least in part, for residual malaria transmission. The impact of this approach will of course depend on the field epidemiological context. Complementary studies will be necessary to characterize ivermectin withdrawal times and potential environmental toxicity.
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Affiliation(s)
- Sié Hermann Pooda
- Université de Dédougou, Dedougou, Burkina Faso
- Centre International de Recherche et Développement pour l’Élevage en zones Sub-humides, Bobo-Dioulasso, Burkina Faso
- Insectarium de Bobo Dioulasso – Campagne d’éradication de la mouche Tsé Tsé et des Trypanosomoses, Bobo-Dioulasso, Burkina Faso
- Université Nazi Boni, Bobo-Dioulasso, Burkina Faso
| | - Nicolas Moiroux
- MIVEGEC, Université de Montpellier-CNRS-IRD, Montpellier, France
| | | | | | | | | | - Issa Sidibé
- Insectarium de Bobo Dioulasso – Campagne d’éradication de la mouche Tsé Tsé et des Trypanosomoses, Bobo-Dioulasso, Burkina Faso
| | | | - Jean-Baptiste Rayaissé
- Centre International de Recherche et Développement pour l’Élevage en zones Sub-humides, Bobo-Dioulasso, Burkina Faso
| | - Roch K. Dabiré
- Institut de Recherche en Sciences de la Santé, Bobo Dioulasso, Burkina Faso
| | - Karine Mouline
- MIVEGEC, Université de Montpellier-CNRS-IRD, Montpellier, France
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Eba K, Habtewold T, Asefa L, Degefa T, Yewhalaw D, Duchateau L. Effect of Ivermectin ® on survivorship and fertility of Anopheles arabiensis in Ethiopia: an in vitro study. Malar J 2023; 22:12. [PMID: 36624480 PMCID: PMC9830892 DOI: 10.1186/s12936-023-04440-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Accepted: 01/03/2023] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Innovative vector control tools are needed to counteract insecticide resistance and residual malaria transmission. One of such innovative methods is an ivermectin (IVM) treatment to reduce vector survival. In this study, a laboratory experiment was conducted to investigate the effect of ivermectin on survivorship, fertility and egg hatchability rate of Anopheles arabiensis in Ethiopia. METHODS An in vitro experiment was conducted using 3-5 days old An. arabiensis adults from a colony maintained at insectary of Tropical and Infectious Diseases Research Center, Jimma University (laboratory population) and Anopheles mosquitoes reared from larvae collected from natural mosquito breeding sites (wild population). The mosquitoes were allowed to feed on cattle blood treated with different doses of ivermectin (0 ng/ml, 5 ng/ml, 10 ng/ml, 20 ng/ml, 40 ng/ml and 80 ng/ml). During each feeding experiment, the mosquitoes were held in cages and blood-fed using a Hemotek feeder. Mortality and egg production were then recorded daily for up to 9 days. Time to death was analysed by a Cox frailty model with replicate as frailty term and source of mosquito (wild versus laboratory), treatment type (ivermectin vs control) and their interaction as categorical fixed effects. Kaplan Meier curves were plotted separately for wild and laboratory populations for a visual interpretation of mosquito survival as a function of treatment. RESULTS Both mosquito source and treatment had a significant effect on survival (P < 0.001), but their interaction was not significant (P = 0.197). Compared to the controls, the death hazard of An. arabiensis that fed on ivermectin-treated blood was 2.3, 3.5, 6.5, 11.5 and 17.9 times that of the control for the 5 ng/ml, 10 ng/ml, 20 ng/ml, 40 ng/ml, and 80 ng/ml dose, respectively. With respect to the number of hatched larvae, hatched pupae and emerged adults per fed mosquitoes, a significant difference was found between the control and the 5 ng/ml dose group (P < 0.001). The number of hatched larvae and pupae, and emerged adults decreased further for the 10 ng/ml dose group and falls to zero for the higher doses. CONCLUSION Treating cattle blood with ivermectin reduced mosquito survival, fertility, egg hatchability, larval development and adult emergence of An. arabiensis in all tested concentrations of ivermectin in both the wild and laboratory populations. Thus, ivermectin application in cattle could be used as a supplementary vector control method to tackle residual malaria transmission and ultimately achieve malaria elimination in Ethiopia.
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Affiliation(s)
- Kasahun Eba
- grid.411903.e0000 0001 2034 9160Department of Environmental Health Science and Technology, Jimma University, P.O. Box 378, Jimma, Ethiopia
| | - Tibebu Habtewold
- grid.7445.20000 0001 2113 8111Department of Life Sciences, Imperial College London, London, UK
| | - Lechisa Asefa
- grid.411903.e0000 0001 2034 9160Department of Environmental Health Science and Technology, Jimma University, P.O. Box 378, Jimma, Ethiopia ,grid.472427.00000 0004 4901 9087Department of Environmental Health Sciences, Bule Hora University, P.O. Box 144, Bule Hora, Ethiopia
| | - Teshome Degefa
- grid.411903.e0000 0001 2034 9160School of Medical Laboratory Sciences, Jimma University, P.O. Box 378, Jimma, Ethiopia
| | - Delenasaw Yewhalaw
- grid.411903.e0000 0001 2034 9160School of Medical Laboratory Sciences, Jimma University, P.O. Box 378, Jimma, Ethiopia ,grid.411903.e0000 0001 2034 9160Tropical and Infectious Diseases Research Center, Jimma University, P.O. Box 378, Jimma, Ethiopia
| | - Luc Duchateau
- grid.5342.00000 0001 2069 7798Biometrics Research Center, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
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16
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Soumare HM, Dabira ED, Camara MM, Jadama L, Gaye PM, Kanteh S, Jawara EA, Njie AK, Sanneh F, Ndiath MO, Lindsay SW, Conteh B, Ceesay S, Mohammed N, Ooko M, Bradley J, Drakeley C, Erhart A, Bousema T, D’Alessandro U. Entomological impact of mass administration of ivermectin and dihydroartemisinin-piperaquine in The Gambia: a cluster-randomized controlled trial. Parasit Vectors 2022; 15:435. [PMID: 36397132 PMCID: PMC9673448 DOI: 10.1186/s13071-022-05557-4] [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: 07/06/2022] [Accepted: 10/16/2022] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Vector control interventions in sub-Saharan Africa rely on insecticide-treated nets and indoor residual spraying. Insecticide resistance, poor coverage of interventions, poor quality nets and changes in vector behavior threaten the effectiveness of these interventions and, consequently, alternative tools are needed. Mosquitoes die after feeding on humans or animals treated with ivermectin (IVM). Mass drug administration (MDA) with IVM could reduce vector survival and decrease malaria transmission. The entomological impact of MDA of combined IVM and dihydroartemisinin-piperaquine was assessed in a community-based, cluster-randomized trial. METHODS A cluster-randomized trial was implemented in 2018 and 2019 in 32 villages in the Upper River Region, The Gambia. The with the inhabitants of 16 intervention villages eligible to receive three monthly rounds of MDA at the beginning of the malaria transmission season. Entomological surveillance with light traps and human landing catches (HLC) was carried out during a 7- to 14-day period after each round of MDA, and then monthly until the end of the year. The mosquitocidal effect of IVM was determined by direct membrane feeding assays. RESULTS Of the 15,017 mosquitoes collected during the study period, 99.65% (n = 14,965) were Anopheles gambiae sensu lato (An. gambiae s.l.), comprising Anopheles arabiensis (56.2%), Anopheles coluzzii (24.5%), Anopheles gambiae sensu stricto (An. gembiae s.s.; 16.0%) and Anopheles funestus sensu lato (An. funestus s.l.; 0.35%). No effect of the intervention on vector parity was observed. Vector density determined on light trap collections was significantly lower in the intervention villages in 2019 (adjusted incidence rate ratio: 0.39; 95% confidence interval [CI]: 0.20, 0.74; P = 0.005) but not in 2018. However, vector density determined in HLC collections was similar in both the intervention and control villages. The entomological inoculation rate was significantly lower in the intervention villages than in the control villages (odds ratio: 0.36, 95% CI: 0.19, 0.70; P = 0·003). Mosquito mortality was significantly higher when blood fed on IVM-treated individuals up to 21 days post-treatment, particularly in adults and individuals with a higher body mass index. CONCLUSION Mass drug administration with IVM decreased vector density and the entomological inoculation rate while the effect on vector parity was less clear. Survival of mosquitoes fed on blood collected from IVM-treated individuals was significantly lower than that in mosquitoes which fed on controls. The influence of host characteristics on mosquito survivorship indicated that dose optimization could improve IVM efficacy. Future detailed entomological evaluation trials in which IVM is administered as stand-alone intervention may elucidate the contribution of this drug to the observed reduction in transmission.
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Affiliation(s)
- Harouna M. Soumare
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Edgard Diniba Dabira
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Muhammed M. Camara
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Lamin Jadama
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Pa Modou Gaye
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Sainey Kanteh
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Ebrima A. Jawara
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Amie Kolleh Njie
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Fatou Sanneh
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Mamadou Ousman Ndiath
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | | | - Bakary Conteh
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Sainey Ceesay
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Nuredin Mohammed
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Michael Ooko
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - John Bradley
- MRC International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK
| | - Chris Drakeley
- Faculty of Infectious & Tropical Diseases, The London School of Hygiene and Tropical Medicine, London, UK
| | - Annette Erhart
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
| | - Teun Bousema
- Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Umberto D’Alessandro
- Medical Research Council Unit The Gambia at the London, School of Hygiene and Tropical Medicine, Banjul, The Gambia
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Dreyer SM, Vaughan JA. Survival and Fecundity of Anopheles stephensi and Anopheles albimanus Mosquitoes (Diptera: Culicidae) After Ingesting Bovine Blood Containing Various Veterinary Systemic Parasiticides. JOURNAL OF MEDICAL ENTOMOLOGY 2022; 59:1700-1709. [PMID: 35934895 PMCID: PMC9473655 DOI: 10.1093/jme/tjac103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Indexed: 05/13/2023]
Abstract
Systemic parasiticides in livestock can control zoophilic malaria vectors that contribute to residual malaria transmission. Membrane feeding techniques were used to screen seven systemic parasiticidic drugs currently in veterinary use for livestock and dogs. Drugs were tested in two laboratory strains of zoophilic Anopheles - A. stephensi (South Asian vector) and A. albimanus (Central American vector). To assess the relative potentials of these drugs, the resultant LC-50 for each drug was compared with what is known about the pharmacokinetic of the drug. Drugs with LC-50 values below the reported maximum plasma concentration of treated animals were considered as showing the most promise for use in the field. Ivermectin and fipronil showed the greatest promise for use in cattle against A. stephensi. Fipronil showed the greatest promise for use in cattle against A. albimanus. Both fluralaner and afoxolaner were highly effective against both mosquito species but pharmacokinetic data for these drugs in cattle are lacking. Eprinomectin, moxidectin and abamectin showed marginal to no promise for either mosquito species. At sublethal doses, ivermectin, fipronil, and afoxolaner (but not fluralaner) significantly reduced the larval production of surviving A. stephensi and A. albimanus. Further testing of candidate systemic parasiticides, including their product formulations, in livestock against field-collected populations of Anopheles is the next logical step toward full implementation of this strategy to manage zoophilic vectors.
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Affiliation(s)
- Staci M Dreyer
- Department of Biology, University of North Dakota, Grand Forks, ND, USA
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18
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Fraccaroli L, Ruiz MD, Perdomo VG, Clausi AN, Balcazar DE, Larocca L, Carrillo C. Broadening the spectrum of ivermectin: Its effect on Trypanosoma cruzi and related trypanosomatids. Front Cell Infect Microbiol 2022; 12:885268. [PMID: 35967842 PMCID: PMC9366347 DOI: 10.3389/fcimb.2022.885268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Accepted: 07/05/2022] [Indexed: 11/22/2022] Open
Abstract
Chagas disease is an endemic American parasitosis, caused by Trypanosoma cruzi. The current therapies, benznidazole (BZN) and nifurtimox (NFX), show limited efficacy and multiple side effects. Thus, there is a need to develop new trypanocidal strategies. Ivermectin (IVM) is a broad-spectrum antiparasitic drug with low human and veterinary toxicity with effects against T. brucei and Leishmania spp. Considering this and its relatively low cost, we evaluate IVM as a potential repurposed trypanocidal drug on T. cruzi and other trypanosomatids. We found that IVM affected, in a dose-dependent manner, the proliferation of T. cruzi epimastigotes as well as the amastigotes and trypomastigotes survival. The Selectivity Index for the amastigote stage with respect to Vero cells was 12. The IVM effect was also observed in Phytomonas jma 066 and Leishmania mexicana proliferation but not in Crithidia fasciculata. On the epimastigote stage, the IVM effect was trypanostatic at 50 μM but trypanocidal at 100 μM. The assays of the drug combinations of IVM with BNZ or NFX showed mainly additive effects among combinations. In silico studies showed that classical structures belonging to glutamate-gated Cl channels, the most common IVM target, are absent in kinetoplastids. However, we found in the studied trypanosomatid genomes one copy for putative IMPα and IMPβ, potential targets for IVM. The putative IMPα genes (with 76% similarity) showed conserved Armadillo domains but lacked the canonical IMPβ binding sequence. These results allowed us to propose a novel molecular target in T. cruzi and suggest IVM as a good candidate for drug repurposing in the Chagas disease context.
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Affiliation(s)
- Laura Fraccaroli
- Laboratorio de Biología Molecular y Bioquímica en Trypanosoma cruzi y otros agentes infecciosos, CONICET for Instituto de Ciencia y Tecnología (ICT) Milstein - Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Buenos Aires, Argentina
- *Correspondence: Laura Fraccaroli, ; Carolina Carrillo,
| | - María Daniela Ruiz
- Laboratorio de Biología Molecular y Bioquímica en Trypanosoma cruzi y otros agentes infecciosos, CONICET for Instituto de Ciencia y Tecnología (ICT) Milstein - Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Buenos Aires, Argentina
| | - Virginia Gabriela Perdomo
- Área Parasitología, Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Rosario, Argentina
| | - Agustina Nicole Clausi
- Laboratorio de Biología Molecular y Bioquímica en Trypanosoma cruzi y otros agentes infecciosos, CONICET for Instituto de Ciencia y Tecnología (ICT) Milstein - Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Buenos Aires, Argentina
| | - Darío Emmanuel Balcazar
- Área Parasitología, Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario (UNR), Rosario, Argentina
| | - Luciana Larocca
- Laboratorio de Biología Molecular y Bioquímica en Trypanosoma cruzi y otros agentes infecciosos, CONICET for Instituto de Ciencia y Tecnología (ICT) Milstein - Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Buenos Aires, Argentina
| | - Carolina Carrillo
- Laboratorio de Biología Molecular y Bioquímica en Trypanosoma cruzi y otros agentes infecciosos, CONICET for Instituto de Ciencia y Tecnología (ICT) Milstein - Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Buenos Aires, Argentina
- *Correspondence: Laura Fraccaroli, ; Carolina Carrillo,
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19
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Dreyer SM, Morin KJ, Magaña M, Pott M, Leiva D, Achee NL, Grieco JP, Vaughan JA. Oral susceptibility to ivermectin is over fifty times greater in a wild population of Anopheles albimanus mosquitoes from Belize than the STECLA laboratory reference strain of this mosquito. Malar J 2022; 21:72. [PMID: 35246147 PMCID: PMC8896111 DOI: 10.1186/s12936-022-04092-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 02/16/2022] [Indexed: 12/12/2022] Open
Abstract
Background The STECLA strain of Anopheles albimanus has been in continuous colony for many years and is the reference strain on which genomic studies for the species are based. Recently, the STECLA strain was demonstrated to be much less susceptible to ivermectin ingested in a blood meal (4-day LC50 of 1468 ng/ml) than all other Anopheles species tested to-date (LC50 values range from 7 to 56 ng/ml). The ability of An. albimanus to survive ingestion of ivermectin at concentrations far beyond that typically found in the blood of ivermectin-treated people or livestock (i.e., 30–70 ng/ml) could invalidate the use of ivermectin as a malaria vector control strategy in areas where An. albimanus is a primary vector. Methods To investigate this, host-seeking An. albimanus were captured in northern Belize and used in membrane feeding bioassays of ivermectin, employing the same methods as described earlier with the STECLA strain. Results Field-collected An. albimanus in Belize were 55 times more susceptible to ingested ivermectin than were the STECLA reference strain. Oral susceptibility to ivermectin in wild An. albimanus from Belize (4-day LC50 of 26 ng/ml) was equivalent to that of other Anopheles species tested. Conclusions Contrary to initial assessments using a highly inbred strain of mosquito, laboratory studies using a field population indicate that ivermectin treatment of livestock could reduce An. albimanus populations in areas of Central America and the Caribbean where malaria transmission may occur. Toxicity screening of ivermectin and other systemic parasiticides for malaria control should examine wild populations of the vector species being targeted.
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Affiliation(s)
| | | | - Marla Magaña
- Belize Vector and Ecology Center, Orange Walk Town, Belize
| | - Marie Pott
- Belize Vector and Ecology Center, Orange Walk Town, Belize
| | - Donovan Leiva
- Belize Vector and Ecology Center, Orange Walk Town, Belize
| | - Nicole L Achee
- Belize Vector and Ecology Center, Orange Walk Town, Belize.,University of Notre Dame, South Bend, IN, 46556, USA
| | - John P Grieco
- Belize Vector and Ecology Center, Orange Walk Town, Belize.,University of Notre Dame, South Bend, IN, 46556, USA
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20
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Morgan J, Salcedo-Sora JE, Triana-Chavez O, Strode C. Expansive and Diverse Phenotypic Landscape of Field Aedes aegypti (Diptera: Culicidae) Larvae with Differential Susceptibility to Temephos: Beyond Metabolic Detoxification. JOURNAL OF MEDICAL ENTOMOLOGY 2022; 59:192-212. [PMID: 34718656 PMCID: PMC8755997 DOI: 10.1093/jme/tjab179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Indexed: 05/08/2023]
Abstract
Arboviruses including dengue, Zika, and chikungunya are amongst the most significant public health concerns worldwide. Arbovirus control relies on the use of insecticides to control the vector mosquito Aedes aegypti (Linnaeus), the success of which is threatened by widespread insecticide resistance. The work presented here profiled the gene expression of Ae. aegypti larvae from field populations of Ae. aegypti with differential susceptibility to temephos originating from two Colombian urban locations, Bello and Cúcuta, previously reported to have distinctive disease incidence, socioeconomics, and climate. We demonstrated that an exclusive field-to-lab (Ae. aegypti strain New Orleans) comparison generates an over estimation of differential gene expression (DGE) and that the inclusion of a geographically relevant field control yields a more discrete, and likely, more specific set of genes. The composition of the obtained DGE profiles is varied, with commonly reported resistance associated genes including detoxifying enzymes having only a small representation. We identify cuticle biosynthesis, ion exchange homeostasis, an extensive number of long noncoding RNAs, and chromatin modelling among the differentially expressed genes in field resistant Ae. aegypti larvae. It was also shown that temephos resistant larvae undertake further gene expression responses when temporarily exposed to temephos. The results from the sampling triangulation approach here contribute a discrete DGE profiling with reduced noise that permitted the observation of a greater gene diversity, increasing the number of potential targets for the control of insecticide resistant mosquitoes and widening our knowledge base on the complex phenotypic network of the Ae. aegypti response to insecticides.
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Affiliation(s)
- Jasmine Morgan
- Department of Biology, Edge Hill University, Ormskirk, UK
| | - J Enrique Salcedo-Sora
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, UK
| | - Omar Triana-Chavez
- Instituto de Biología, Facultad de Ciencias Exactas y Naturales (FCEN), University of Antioquia, Medellín, Colombia
| | - Clare Strode
- Department of Biology, Edge Hill University, Ormskirk, UK
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21
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Wamaket N, Khamprapa O, Chainarin S, Thamsawet P, Ninsaeng U, Thongsalee S, Suwan V, Sakolvaree J, Takhampunya R, Davidson SA, McCardle PW, Sa-Angchai P, Mukaka M, Kiattibutr K, Khamsiriwatchara A, Nguitragool W, Sattabongkot J, Sirichaisinthop J, Kobylinski KC. Anopheles bionomics in a malaria endemic area of southern Thailand. Parasit Vectors 2021; 14:378. [PMID: 34315509 PMCID: PMC8317318 DOI: 10.1186/s13071-021-04870-8] [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: 04/09/2021] [Accepted: 07/02/2021] [Indexed: 12/26/2022] Open
Abstract
Background Ivermectin mass drug administration (MDA) could accelerate malaria elimination in the Greater Mekong Subregion. This study was performed to characterize the bionomics of Anopheles in Surat Thani province, Thailand. Methods Mosquitoes were collected via human landing collections between February and October 2019. Anopheles mosquitoes were morphologically identified to species. Primary Anopheles malaria vectors were dissected to assess parity status, and a subset were evaluated for molecular identification and Plasmodium detection. Results A total of 17,348 mosquitoes were collected during the study period; of these, 5777 were Anopheles mosquitoes. Morphological studies identified 15 Anopheles species, of which the most abundant were Anopheles minimus (s.l.) (87.16%, n = 5035), An. dirus s.l. (7.05%, n = 407) and An. barbirostris s.l. (2.86%, n = 165). Molecular identification confirmed that of the An. minimus s.l. mosquitoes collected, 99.80% were An. minimus (s.s.) (n = 484) and 0.2% were An. aconitus (n = 1), of the An. dirus (s.l.) collected, 100% were An. baimaii (n = 348), and of the An. maculatus (s.l.) collected, 93.62% were An. maculatus (s.s.) (n = 44) and 6.38% were An. sawadwongporni (n = 3). No Anopheles mosquito tested was Plasmodium positive (0/879). An average of 11.46 Anopheles were captured per collector per night. There were differences between species in hour of collection (Kruskal–Wallis H-test: χ2 = 80.89, P < 0.0001, n = 5666), with more An. barbirostris (s.l.) and An. maculatus (s.l.) caught earlier compared to An. minimus (s.l.) (P = 0.0001 and P < 0.0001, respectively) and An. dirus (s.l.) (P = 0.0082 and P < 0.001, respectively). The proportion of parous An. minimus (s.l.) captured by hour increased throughout the night (Wald Chi-square: χ2 = 17.31, P = 0.000, odds ratio = 1.0535, 95% confidence interval 1.0279–1.0796, n = 3400). Overall, An. minimus (s.l.) parity was 67.68% (2375/3509) with an intra-cluster correlation of 0.0378. A power calculation determined that an An. minimus (s.l.) parity reduction treatment effect size = 34%, with four clusters per treatment arm and a minimum of 300 mosquitoes dissected per cluster, at an α = 0.05, will provide 82% power to detect a significant difference following ivermectin MDA. Conclusions The study area in Surat Thani province is an ideal location to evaluate the impact of ivermectin MDA on An. minimus parity. Graphical abstract ![]()
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Affiliation(s)
- Narenrit Wamaket
- Department of Entomology, Armed Forces Research Institute of Medical Sciences, Ratchathewi, Bangkok, Thailand.,Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Ratchathewi, Bangkok, Thailand
| | - Oranicha Khamprapa
- Department of Entomology, Armed Forces Research Institute of Medical Sciences, Ratchathewi, Bangkok, Thailand.,Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Ratchathewi, Bangkok, Thailand
| | - Sittinont Chainarin
- Department of Entomology, Armed Forces Research Institute of Medical Sciences, Ratchathewi, Bangkok, Thailand.,Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Ratchathewi, Bangkok, Thailand
| | - Panisa Thamsawet
- Surat Thani Vector-Borne Diseases Control Center 11.3, Muang, Surat Thani, Thailand
| | - Ubolrat Ninsaeng
- Surat Thani Vector-Borne Diseases Control Center 11.3, Muang, Surat Thani, Thailand
| | - Suttipong Thongsalee
- Surat Thani Vector-Borne Diseases Control Center 11.3, Muang, Surat Thani, Thailand
| | - Veerast Suwan
- Surat Thani Vector-Borne Diseases Control Center 11.3, Muang, Surat Thani, Thailand
| | - Jira Sakolvaree
- Department of Entomology, Armed Forces Research Institute of Medical Sciences, Ratchathewi, Bangkok, Thailand
| | - Ratree Takhampunya
- Department of Entomology, Armed Forces Research Institute of Medical Sciences, Ratchathewi, Bangkok, Thailand
| | - Silas A Davidson
- Department of Entomology, Armed Forces Research Institute of Medical Sciences, Ratchathewi, Bangkok, Thailand
| | - Patrick W McCardle
- Department of Entomology, Armed Forces Research Institute of Medical Sciences, Ratchathewi, Bangkok, Thailand
| | - Patiwat Sa-Angchai
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Ratchathewi, Bangkok, Thailand
| | - Mavuto Mukaka
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Ratchathewi, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Kirakorn Kiattibutr
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Ratchathewi, Bangkok, Thailand
| | - Amnat Khamsiriwatchara
- Center of Excellence for Biomedical and Public Health Informatics, Faculty of Tropical Medicine, Mahidol University, Ratchathewi, Bangkok, Thailand
| | - Wang Nguitragool
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Ratchathewi, Bangkok, Thailand.,Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Ratchathewi, Bangkok, Thailand
| | - Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Ratchathewi, Bangkok, Thailand
| | | | - Kevin C Kobylinski
- Department of Entomology, Armed Forces Research Institute of Medical Sciences, Ratchathewi, Bangkok, Thailand.
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22
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de Souza DK, Thomas R, Bradley J, Leyrat C, Boakye DA, Okebe J. Ivermectin treatment in humans for reducing malaria transmission. Cochrane Database Syst Rev 2021; 6:CD013117. [PMID: 34184757 PMCID: PMC8240090 DOI: 10.1002/14651858.cd013117.pub2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND Malaria is transmitted through the bite of Plasmodium-infected adult female Anopheles mosquitoes. Ivermectin, an anti-parasitic drug, acts by killing mosquitoes that are exposed to the drug while feeding on the blood of people (known as blood feeds) who have ingested the drug. This effect on mosquitoes has been demonstrated by individual randomized trials. This effect has generated interest in using ivermectin as a tool for malaria control. OBJECTIVES To assess the effect of community administration of ivermectin on malaria transmission. SEARCH METHODS We searched the Cochrane Infectious Diseases Group (CIDG) Specialized Register, CENTRAL, MEDLINE, Embase, LILACS, Science Citation index - expanded, the World Health Organization (WHO) International Clinical Trials Registry Platform, ClinicalTrials.gov, and the National Institutes of Health (NIH) RePORTER database to 14 January 2021. We checked the reference lists of included studies for other potentially relevant studies, and contacted researchers working in the field for unpublished and ongoing trials. SELECTION CRITERIA We included cluster-randomized controlled trials (cRCTs) that compared ivermectin, as single or multiple doses, with a control treatment or placebo given to populations living in malaria-endemic areas, in the context of mass drug administration. Primary outcomes were prevalence of malaria parasite infection and incidence of clinical malaria in the community. DATA COLLECTION AND ANALYSIS Two review authors independently extracted data on the number of events and the number of participants in each trial arm at the time of assessment. For rate data, we noted the total time at risk in each trial arm. To assess risk of bias, we used Cochrane's RoB 2 tool for cRCTs. We documented the method of data analysis, any adjustments for clustering or other covariates, and recorded the estimate of the intra-cluster correlation (ICC) coefficient. We re-analysed the trial data provided by the trial authors to adjust for cluster effects. We used a Poisson mixed-effect model with small sample size correction, and a cluster-level analysis using the linear weighted model to adequately adjust for clustering. MAIN RESULTS: We included one cRCT and identified six ongoing trials. The included cRCT examined the incidence of malaria in eight villages in Burkina Faso, randomized to two arms. Both trial arms received a single dose of ivermectin 150 µg/kg to 200 µg/kg, together with a dose of albendazole. The villages in the intervention arm received an additional five doses of ivermectin, once every three weeks. Children were enrolled into an active cohort, in which they were repeatedly screened for malaria infection. The primary outcome was the cumulative incidence of uncomplicated malaria in a cohort of children aged five years and younger, over the 18-week study. We judged the study to be at high risk of bias, as the analysis did not account for clustering or correlation between participants in the same village. The study did not demonstrate an effect of Ivermectin on the cumulative incidence of uncomplicated malaria in the cohort of children over the 18-week study (risk ratio 0.86, 95% confidence interval (CI) 0.62 to 1.17; P = 0.2607; very low-certainty evidence). AUTHORS' CONCLUSIONS We are uncertain whether community administration of ivermectin has an effect on malaria transmission, based on one trial published to date.
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Affiliation(s)
- Dziedzom K de Souza
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Rebecca Thomas
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - John Bradley
- MRC International Statistics and Epidemiology Group, London School of Hygiene & Tropical Medicine, London, UK
| | - Clemence Leyrat
- Medical Statistics Department, London School of Hygiene & Tropical Medicine, London, UK
| | - Daniel A Boakye
- Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra, Ghana
| | - Joseph Okebe
- Department of International Public Health, Liverpool School of Tropical Medicine, Liverpool, UK
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23
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Omitola OO, Umunnakwe CU, Bayegun AA, Anifowose SA, Mogaji HO, Oluwole AS, Odoemene SN, Awolola TS, Osipitan AA, Sam-Wobo SO, Ekpo UF. Impacts of ivermectin mass drug administration for onchocerciasis on mosquito populations of Ogun state, Nigeria. Parasit Vectors 2021; 14:212. [PMID: 33879232 PMCID: PMC8056593 DOI: 10.1186/s13071-021-04716-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 04/01/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The impact of single-dose mass drug administration (MDA) of ivermectin for onchocerciasis on mosquito populations was investigated in Ogun State, Nigeria. METHODS Indoor and outdoor collection of mosquitoes was carried out in two intervention (IC) and two control communities (CC) at three different periods: pre-MDA (baseline), 2-3 days after MDA and 13-14 days after MDA. The density and parity rate of female Anopheles and Culex mosquitoes were determined and compared. Environmental and climatic data of study locations were obtained to perform generalized linear model analysis. RESULTS A total of 1399 female mosquitoes were collected, including 1227 Anopheles and 172 Culex mosquitoes. There was a similar magnitude of reduction in the indoor density of Anopheles by 29% in the IC and CC 2-3 days post-MDA but the reduction in indoor parity rate was significantly higher (p = 0.021) in the IC, reducing by more than 50%. In the IC, observation of a significant reduction at 2-3 days post-MDA was consistent for both the indoor density (1.43 to 1.02) and indoor parity rate (95.35% to 44.26%) of Anopheles mosquitoes. The indoor parity rate of Anopheles remained significantly reduced (75.86%) 13-14 post-MDA. On the other hand, the indoor density of Culex increased from 0.07 to 0.10 at 2-3 days post-MDA while the indoor parity rate of Culex did not change. The outdoor density of Anopheles in the IC increased (p = 0.394) from 0.58 to 0.90 at 2-3 days post-MDA; a similar observation was consistent for the outdoor density (2.83 to 3.90) and outdoor parity rate (70.59% to 97.44%) of Culex, while the outdoor parity rate of Anopheles reduced from 85.71 to 66.67% at 2-3 days post-MDA. A generalized linear model showed that ivermectin MDA significantly caused a reduction in both the indoor density (p < 0.001) and indoor parity rate (p = 0.003) of Anopheles in the IC. CONCLUSION Ivermectin MDA resulted in the reduction of both the survival and density of Anopheles mosquitoes. This has strong implications for malaria transmission, which depends strongly on vector survival.
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Affiliation(s)
- Olaitan Olamide Omitola
- Department of Pure and Applied Zoology, Federal University of Agriculture, Abeokuta, Ogun, Nigeria.
| | | | - Adedotun Ayodeji Bayegun
- Department of Pure and Applied Zoology, Federal University of Agriculture, Abeokuta, Ogun, Nigeria
| | | | - Hammed Oladeji Mogaji
- Department of Animal and Environmental Biology, Federal University Oye Ekiti, Ekiti, Nigeria
| | | | | | - Taiwo Sam Awolola
- Molecular Entomology and Vector Control Research Laboratory, Public Health Division, Nigeria Institute of Medical Research, Lagos, Nigeria
| | | | - Sammy Olufemi Sam-Wobo
- Department of Pure and Applied Zoology, Federal University of Agriculture, Abeokuta, Ogun, Nigeria
| | - Uwem Friday Ekpo
- Department of Pure and Applied Zoology, Federal University of Agriculture, Abeokuta, Ogun, Nigeria.
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24
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Pessanha de Carvalho L, Kreidenweiss A, Held J. Drug Repurposing: A Review of Old and New Antibiotics for the Treatment of Malaria: Identifying Antibiotics with a Fast Onset of Antiplasmodial Action. Molecules 2021; 26:2304. [PMID: 33921170 PMCID: PMC8071546 DOI: 10.3390/molecules26082304] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 04/12/2021] [Accepted: 04/13/2021] [Indexed: 11/24/2022] Open
Abstract
Malaria is one of the most life-threatening infectious diseases and constitutes a major health problem, especially in Africa. Although artemisinin combination therapies remain efficacious to treat malaria, the emergence of resistant parasites emphasizes the urgent need of new alternative chemotherapies. One strategy is the repurposing of existing drugs. Herein, we reviewed the antimalarial effects of marketed antibiotics, and described in detail the fast-acting antibiotics that showed activity in nanomolar concentrations. Antibiotics have been used for prophylaxis and treatment of malaria for many years and are of particular interest because they might exert a different mode of action than current antimalarials, and can be used simultaneously to treat concomitant bacterial infections.
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Affiliation(s)
- Lais Pessanha de Carvalho
- Institute of Tropical Medicine, University of Tuebingen, 72074 Tuebingen, Germany; (L.P.d.C.); (A.K.)
| | - Andrea Kreidenweiss
- Institute of Tropical Medicine, University of Tuebingen, 72074 Tuebingen, Germany; (L.P.d.C.); (A.K.)
- Centre de Recherches Medicales de Lambaréné (CERMEL), Lambaréné BP 242, Gabon
| | - Jana Held
- Institute of Tropical Medicine, University of Tuebingen, 72074 Tuebingen, Germany; (L.P.d.C.); (A.K.)
- Centre de Recherches Medicales de Lambaréné (CERMEL), Lambaréné BP 242, Gabon
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25
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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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26
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A systematic review and an individual patient data meta-analysis of ivermectin use in children weighing less than fifteen kilograms: Is it time to reconsider the current contraindication? PLoS Negl Trop Dis 2021; 15:e0009144. [PMID: 33730099 PMCID: PMC7968658 DOI: 10.1371/journal.pntd.0009144] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 01/13/2021] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Oral ivermectin is a safe broad spectrum anthelminthic used for treating several neglected tropical diseases (NTDs). Currently, ivermectin use is contraindicated in children weighing less than 15 kg, restricting access to this drug for the treatment of NTDs. Here we provide an updated systematic review of the literature and we conducted an individual-level patient data (IPD) meta-analysis describing the safety of ivermectin in children weighing less than 15 kg. METHODOLOGY/PRINCIPAL FINDINGS A systematic review was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) for IPD guidelines by searching MEDLINE via PubMed, Web of Science, Ovid Embase, LILACS, Cochrane Database of Systematic Reviews, TOXLINE for all clinical trials, case series, case reports, and database entries for reports on the use of ivermectin in children weighing less than 15 kg that were published between 1 January 1980 to 25 October 2019. The protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO): CRD42017056515. A total of 3,730 publications were identified, 97 were selected for potential inclusion, but only 17 sources describing 15 studies met the minimum criteria which consisted of known weights of children less than 15 kg linked to possible adverse events, and provided comprehensive IPD. A total of 1,088 children weighing less than 15 kg were administered oral ivermectin for one of the following indications: scabies, mass drug administration for scabies control, crusted scabies, cutaneous larva migrans, myiasis, pthiriasis, strongyloidiasis, trichuriasis, and parasitic disease of unknown origin. Overall a total of 1.4% (15/1,088) of children experienced 18 adverse events all of which were mild and self-limiting. No serious adverse events were reported. CONCLUSIONS/SIGNIFICANCE Existing limited data suggest that oral ivermectin in children weighing less than 15 kilograms is safe. Data from well-designed clinical trials are needed to provide further assurance.
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27
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Tipthara P, Kobylinski KC, Godejohann M, Hanboonkunupakarn B, Roth A, Adams JH, White NJ, Jittamala P, Day NPJ, Tarning J. Identification of the metabolites of ivermectin in humans. Pharmacol Res Perspect 2021; 9:e00712. [PMID: 33497030 PMCID: PMC7836931 DOI: 10.1002/prp2.712] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 12/04/2020] [Accepted: 12/07/2020] [Indexed: 12/11/2022] Open
Abstract
Mass drug administration of ivermectin has been proposed as a possible malaria elimination tool. Ivermectin exhibits a mosquito-lethal effect well beyond its biological half-life, suggesting the presence of active slowly eliminated metabolites. Human liver microsomes, primary human hepatocytes, and whole blood from healthy volunteers given oral ivermectin were used to identify ivermectin metabolites by ultra-high performance liquid chromatography coupled with high-resolution mass spectrometry. The molecular structures of metabolites were determined by mass spectrometry and verified by nuclear magnetic resonance. Pure cytochrome P450 enzyme isoforms were used to elucidate the metabolic pathways. Thirteen different metabolites (M1-M13) were identified after incubation of ivermectin with human liver microsomes. Three (M1, M3, and M6) were the major metabolites found in microsomes, hepatocytes, and blood from volunteers after oral ivermectin administration. The chemical structure, defined by LC-MS/MS and NMR, indicated that M1 is 3″-O-demethyl ivermectin, M3 is 4-hydroxymethyl ivermectin, and M6 is 3″-O-demethyl, 4-hydroxymethyl ivermectin. Metabolic pathway evaluations with characterized cytochrome P450 enzymes showed that M1, M3, and M6 were produced primarily by CYP3A4, and that M1 was also produced to a small extent by CYP3A5. Demethylated (M1) and hydroxylated (M3) ivermectin were the main human in vivo metabolites. Further studies are needed to characterize the pharmacokinetic properties and mosquito-lethal activity of these metabolites.
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Affiliation(s)
- Phornpimon Tipthara
- Mahidol Oxford Tropical Medicine Research UnitFaculty of Tropical MedicineMahidol UniversityBangkokThailand
| | - Kevin C. Kobylinski
- Department of EntomologyArmed Forces Research Institute of Medical SciencesBangkokThailand
| | | | - Borimas Hanboonkunupakarn
- Mahidol Oxford Tropical Medicine Research UnitFaculty of Tropical MedicineMahidol UniversityBangkokThailand
- Department of Clinical Tropical MedicineFaculty of Tropical MedicineMahidol UniversityBangkokThailand
| | - Alison Roth
- Center for Global Health and Infectious Diseases ResearchCollege of Public HealthUniversity of South FloridaTampaFLUSA
- Department of Drug DiscoveryExperimental Therapeutics BranchWalter Reed Army Institute of ResearchSilver SpringMDUSA
| | - John H. Adams
- Center for Global Health and Infectious Diseases ResearchCollege of Public HealthUniversity of South FloridaTampaFLUSA
| | - Nicholas J. White
- Mahidol Oxford Tropical Medicine Research UnitFaculty of Tropical MedicineMahidol UniversityBangkokThailand
- Centre for Tropical Medicine and Global HealthNuffield Department of Clinical MedicineUniversity of OxfordOxfordUnited Kingdom
| | - Podjanee Jittamala
- Mahidol Oxford Tropical Medicine Research UnitFaculty of Tropical MedicineMahidol UniversityBangkokThailand
- Department of Tropical HygieneFaculty of Tropical MedicineMahidol UniversityBangkokThailand
| | - Nicholas P. J. Day
- Mahidol Oxford Tropical Medicine Research UnitFaculty of Tropical MedicineMahidol UniversityBangkokThailand
- Centre for Tropical Medicine and Global HealthNuffield Department of Clinical MedicineUniversity of OxfordOxfordUnited Kingdom
| | - Joel Tarning
- Mahidol Oxford Tropical Medicine Research UnitFaculty of Tropical MedicineMahidol UniversityBangkokThailand
- Centre for Tropical Medicine and Global HealthNuffield Department of Clinical MedicineUniversity of OxfordOxfordUnited Kingdom
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28
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Kinobe RT, Owens L. A systematic review of experimental evidence for antiviral effects of ivermectin and an in silico analysis of ivermectin's possible mode of action against SARS-CoV-2. Fundam Clin Pharmacol 2021; 35:260-276. [PMID: 33427370 PMCID: PMC8013482 DOI: 10.1111/fcp.12644] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 12/18/2020] [Accepted: 01/07/2021] [Indexed: 01/02/2023]
Abstract
Viral infections remain a major cause of economic loss with an unmet need for novel therapeutic agents. Ivermectin is a putative antiviral compound; the proposed mechanism is the inhibition of nuclear translocation of viral proteins, facilitated by mammalian host importins, a necessary process for propagation of infections. We systematically reviewed the evidence for the applicability of ivermectin against viral infections including SARS‐CoV‐2 regarding efficacy, mechanisms and selective toxicity. The SARS‐CoV‐2 genome was mined to determine potential nuclear location signals for ivermectin and meta‐analyses for in vivo studies included all comparators over time, dose range and viral replication in multiple organs. Ivermectin inhibited the replication of many viruses including those in Flaviviridae, Circoviridae and Coronaviridae families in vitro. Real and mock nuclear location signals were identified in SARS‐CoV‐2, a potential target for ivermectin and predicting a sequestration bait for importin β, stopping infected cells from reaching a virus‐resistant state. While pharmacokinetic evaluations indicate that ivermectin could be toxic if applied based on in vitro studies, inhibition of viral replication in vivo was shown for Porcine circovirus in piglets and Suid herpesvirus in mice. Overall standardized mean differences and 95% confidence intervals for ivermectin versus controls were −4.43 (−5.81, −3.04), p < 0.00001. Based on current results, the potential for repurposing ivermectin as an antiviral agent is promising. However, further work is needed to reconcile in vitro studies with clinical efficacy. Developing ivermectin as an additional antiviral agent should be pursued with an emphasis on pre‐clinical trials in validated models of infection.
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Affiliation(s)
- Robert T Kinobe
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, Australia
| | - Leigh Owens
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, Australia
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29
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High concentrations of membrane-fed ivermectin are required for substantial lethal and sublethal impacts on Aedes aegypti. Parasit Vectors 2021; 14:9. [PMID: 33407825 PMCID: PMC7789309 DOI: 10.1186/s13071-020-04512-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 12/01/2020] [Indexed: 12/25/2022] Open
Abstract
Background With widespread insecticide resistance in mosquito vectors, there is a pressing need to evaluate alternatives with different modes of action. Blood containing the antihelminthic drug ivermectin has been shown to have lethal and sub-lethal effects on mosquitoes. Almost all work to date has been on Anopheles spp., but impacts on other anthropophagic vectors could provide new options for their control, or additional value to anti-malarial ivermectin programmes. Methods Using dose-response assays, we evaluated the effects of ivermectin delivered by membrane feeding on daily mortality (up to 14 days post-blood feed) and fecundity of an Indian strain of Aedes aegypti. Results The 7-day lethal concentration of ivermectin required to kill 50% of adult mosquitoes was calculated to be 178.6 ng/ml (95% confidence intervals 142.3–218.4) for Ae. aegypti, which is much higher than that recorded for Anopheles spp. in any previous study. In addition, significant effects on fecundity and egg hatch rates were only recorded at high ivermectin concentrations (≥ 250 ng/ul). Conclusion Our results suggest that levels of ivermectin present in human blood at current dosing regimes in mass drug administration campaigns, or even those in a recent higher-dose anti-malaria trial, are unlikely to have a substantial impact on Ae. aegypti. Moreover, owing to the strong anthropophagy of Ae. aegypti, delivery of higher levels of ivermectin in livestock blood is also unlikely to be an effective option for its control. However, other potential toxic impacts of ivermectin metabolites, accumulation in tissues, sublethal effects on behaviour, or antiviral action might increase the efficacy of ivermectin against Ae. aegypti and the arboviral diseases it transmits, and require further investigation.![]()
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Dabira ED, Soumare HM, Lindsay SW, Conteh B, Ceesay F, Bradley J, Kositz C, Broekhuizen H, Kandeh B, Fehr AE, Nieto-Sanchez C, Ribera JM, Peeters Grietens K, Smit MR, Drakeley C, Bousema T, Achan J, D'Alessandro U. Mass Drug Administration With High-Dose Ivermectin and Dihydroartemisinin-Piperaquine for Malaria Elimination in an Area of Low Transmission With High Coverage of Malaria Control Interventions: Protocol for the MASSIV Cluster Randomized Clinical Trial. JMIR Res Protoc 2020; 9:e20904. [PMID: 33211022 PMCID: PMC7714640 DOI: 10.2196/20904] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 07/28/2020] [Accepted: 08/03/2020] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND With a decline in malaria burden, innovative interventions and tools are required to reduce malaria transmission further. Mass drug administration (MDA) of artemisinin-based combination therapy (ACT) has been identified as a potential tool to further reduce malaria transmission, where coverage of vector control interventions is already high. However, the impact is limited in time. Combining an ACT with an endectocide treatment that is able to reduce vector survival, such as ivermectin (IVM), could increase the impact of MDA and offer a new tool to reduce malaria transmission. OBJECTIVE The study objective is to evaluate the impact of MDA with IVM plus dihydroartemisinin-piperaquine (DP) on malaria transmission in an area with high coverage of malaria control interventions. METHODS The study is a cluster randomized trial in the Upper River Region of The Gambia and included 32 villages (16 control and 16 intervention). A buffer zone of ~2 km was created around all intervention clusters. MDA with IVM plus DP was implemented in all intervention villages and the buffer zones; control villages received standard malaria interventions according to the Gambian National Malaria Control Program plans. RESULTS The MDA campaigns were carried out from August to October 2018 for the first year and from July to September 2019 for the second year. Statistical analysis will commence once the database is completed, cleaned, and locked. CONCLUSIONS This is the first cluster randomized clinical trial of MDA with IVM plus DP. The results will provide evidence on the impact of MDA with IVM plus DP on malaria transmission. TRIAL REGISTRATION ClinicalTrials.gov NCT03576313; https://clinicaltrials.gov/ct2/show/NCT03576313. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID) DERR1-10.2196/20904.
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Affiliation(s)
- Edgard Diniba Dabira
- Medical Research Council Unit Gambia, London School of Hygiene and Tropical Medicine, Banjul, Gambia
| | - Harouna M Soumare
- Medical Research Council Unit Gambia, London School of Hygiene and Tropical Medicine, Banjul, Gambia
| | - Steven W Lindsay
- Department of Biosciences, Durham University, Durham, United Kingdom
| | - Bakary Conteh
- Medical Research Council Unit Gambia, London School of Hygiene and Tropical Medicine, Banjul, Gambia
| | - Fatima Ceesay
- Medical Research Council Unit Gambia, London School of Hygiene and Tropical Medicine, Banjul, Gambia
| | - John Bradley
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Christian Kositz
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | | - Balla Kandeh
- National Malaria Control Program, The Gambia, Banjul, Gambia
| | - Alexandra E Fehr
- Medical Anthropology Unit, Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium
- Vrije Universiteit Amsterdam, Athena Institute, Amsterdam, Netherlands
| | - Claudia Nieto-Sanchez
- Medical Anthropology Unit, Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium
| | - Joan Muela Ribera
- Medial Anthropology Research Center, Universitat Rovira i Virgili, Tarragona, Spain
| | - Koen Peeters Grietens
- Medical Anthropology Unit, Department of Public Health, Institute of Tropical Medicine, Antwerp, Belgium
| | - Menno Roderick Smit
- Amsterdam Centre for Global Child Health, Emma Children's Hospital, Amsterdam University Medical Centres, Amsterdam, The Netherlands, Amsterdam, Netherlands
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Chris Drakeley
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Teun Bousema
- Radboud University Medical Centre, Nijmegen, Netherlands
| | - Jane Achan
- Medical Research Council Unit Gambia, London School of Hygiene and Tropical Medicine, Banjul, Gambia
| | - Umberto D'Alessandro
- Medical Research Council Unit Gambia, London School of Hygiene and Tropical Medicine, Banjul, Gambia
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Safety, Pharmacokinetics, and Activity of High-Dose Ivermectin and Chloroquine against the Liver Stage of Plasmodium cynomolgi Infection in Rhesus Macaques. Antimicrob Agents Chemother 2020; 64:AAC.00741-20. [PMID: 32660993 PMCID: PMC7449176 DOI: 10.1128/aac.00741-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Accepted: 06/30/2020] [Indexed: 12/11/2022] Open
Abstract
Previously, ivermectin (1 to 10 mg/kg of body weight) was shown to inhibit the liver-stage development of Plasmodium berghei in orally dosed mice. Here, ivermectin showed inhibition of the in vitro development of Plasmodium cynomolgi schizonts (50% inhibitory concentration [IC50], 10.42 μM) and hypnozoites (IC50, 29.24 μM) in primary macaque hepatocytes when administered as a high dose prophylactically but not when administered in radical cure mode. Previously, ivermectin (1 to 10 mg/kg of body weight) was shown to inhibit the liver-stage development of Plasmodium berghei in orally dosed mice. Here, ivermectin showed inhibition of the in vitro development of Plasmodium cynomolgi schizonts (50% inhibitory concentration [IC50], 10.42 μM) and hypnozoites (IC50, 29.24 μM) in primary macaque hepatocytes when administered as a high dose prophylactically but not when administered in radical cure mode. The safety, pharmacokinetics, and efficacy of oral ivermectin (0.3, 0.6, and 1.2 mg/kg) with and without chloroquine (10 mg/kg) administered for 7 consecutive days were evaluated for prophylaxis or radical cure of P. cynomolgi liver stages in rhesus macaques. No inhibition or delay to blood-stage P. cynomolgi parasitemia was observed at any ivermectin dose (0.3, 0.6, and 1.2 mg/kg). Ivermectin (0.6 and 1.2 mg/kg) and chloroquine (10 mg/kg) in combination were well-tolerated with no adverse events and no significant pharmacokinetic drug-drug interactions observed. Repeated daily ivermectin administration for 7 days did not inhibit ivermectin bioavailability. It was recently demonstrated that both ivermectin and chloroquine inhibit replication of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in vitro. Further ivermectin and chloroquine trials in humans are warranted to evaluate their role in Plasmodium vivax control and as adjunctive therapies against COVID-19 infections.
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Repurposing Drugs to Fight Hepatic Malaria Parasites. Molecules 2020; 25:molecules25153409. [PMID: 32731386 PMCID: PMC7435416 DOI: 10.3390/molecules25153409] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/23/2020] [Accepted: 07/24/2020] [Indexed: 12/16/2022] Open
Abstract
Malaria remains one of the most prevalent infectious diseases worldwide, primarily affecting some of the most vulnerable populations around the globe. Despite achievements in the treatment of this devastating disease, there is still an urgent need for the discovery of new drugs that tackle infection by Plasmodium parasites. However, de novo drug development is a costly and time-consuming process. An alternative strategy is to evaluate the anti-plasmodial activity of compounds that are already approved for other purposes, an approach known as drug repurposing. Here, we will review efforts to assess the anti-plasmodial activity of existing drugs, with an emphasis on the obligatory and clinically silent liver stage of infection. We will also review the current knowledge on the classes of compounds that might be therapeutically relevant against Plasmodium in the context of other communicable diseases that are prevalent in regions where malaria is endemic. Repositioning existing compounds may constitute a faster solution to the current gap of prophylactic and therapeutic drugs that act on Plasmodium parasites, overall contributing to the global effort of malaria eradication.
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Dieng S, Ba EH, Cissé B, Sallah K, Guindo A, Ouedraogo B, Piarroux M, Rebaudet S, Piarroux R, Landier J, Sokhna C, Gaudart J. Spatio-temporal variation of malaria hotspots in Central Senegal, 2008-2012. BMC Infect Dis 2020; 20:424. [PMID: 32552759 PMCID: PMC7301493 DOI: 10.1186/s12879-020-05145-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 06/10/2020] [Indexed: 12/01/2022] Open
Abstract
Background In malaria endemic areas, identifying spatio-temporal hotspots is becoming an important element of innovative control strategies targeting transmission bottlenecks. The aim of this work was to describe the spatio-temporal variation of malaria hotspots in central Senegal and to identify the meteorological, environmental, and preventive factors that influence this variation. Methods This study analysed the weekly incidence of malaria cases recorded from 2008 to 2012 in 575 villages of central Senegal (total population approximately 500,000) as part of a trial of seasonal malaria chemoprevention (SMC). Data on weekly rainfall and annual vegetation types were obtained for each village through remote sensing. The time series of weekly malaria incidence for the entire study area was divided into periods of high and low transmission using change-point analysis. Malaria hotspots were detected during each transmission period with the SaTScan method. The effects of rainfall, vegetation type, and SMC intervention on the spatio-temporal variation of malaria hotspots were assessed using a General Additive Mixed Model. Results The malaria incidence for the entire area varied between 0 and 115.34 cases/100,000 person weeks during the study period. During high transmission periods, the cumulative malaria incidence rate varied between 7.53 and 38.1 cases/100,000 person-weeks, and the number of hotspot villages varied between 62 and 147. During low transmission periods, the cumulative malaria incidence rate varied between 0.83 and 2.73 cases/100,000 person-weeks, and the number of hotspot villages varied between 10 and 43. Villages with SMC were less likely to be hotspots (OR = 0.48, IC95%: 0.33–0.68). The association between rainfall and hotspot status was non-linear and depended on both vegetation type and amount of rainfall. The association between village location in the study area and hotspot status was also shown. Conclusion In our study, malaria hotspots varied over space and time according to a combination of meteorological, environmental, and preventive factors. By taking into consideration the environmental and meteorological characteristics common to all hotspots, monitoring of these factors could lead targeted public health interventions at the local level. Moreover, spatial hotspots and foci of malaria persisting during LTPs need to be further addressed. Trial registration The data used in this work were obtained from a clinical trial registered on July 10, 2008 at www.clinicaltrials.gov under NCT00712374.
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Affiliation(s)
- Sokhna Dieng
- Aix Marseille Univ, IRD, INSERM, SESSTIM, Marseille, France. .,Ecole des Hautes Etudes en Santé Publique, Rennes, France.
| | - El Hadj Ba
- UMR VITROME, Campus International IRD-UCAD de l'IRD, Dakar, Sénégal
| | - Badara Cissé
- Institut de Recherche en Santé, de Surveillance Épidémiologique et de Formation (IRESSEF) Diamniadio, Dakar, Sénégal
| | - Kankoe Sallah
- Aix Marseille Univ, IRD, INSERM, SESSTIM, Marseille, France.,AP-HP, Hôpital Bichat, Unité de Recherche Clinique PNVS, Paris, France
| | - Abdoulaye Guindo
- Aix Marseille Univ, IRD, INSERM, SESSTIM, Marseille, France.,Research and Training Center - Ogobara K Doumbo, FMOS-FAPH, Mali-NIAID-ICER, Université des Sciences, des Techniques et des Technologies de Bamako, Bamako, Mali
| | - Boukary Ouedraogo
- Aix Marseille Univ, IRD, INSERM, SESSTIM, Marseille, France.,Direction des Systèmes d'Information en santé, Ministère de la santé, Ouagadougou, Burkina Faso
| | - Martine Piarroux
- French Armed Forces Center for Epidemiology and Public Health (CESPA), Marseille, France
| | - Stanislas Rebaudet
- APHM, Assistance Publique - Hôpitaux de Marseille, Marseille, France.,Hôpital Européen, Marseille, France
| | - Renaud Piarroux
- Sorbonne Université, INSERM, Institut Pierre-Louis d'Epidémiologie et de Santé Publique, AP-HP, Hôpital Pitié-Salpêtrière, Paris, France
| | - Jordi Landier
- Aix Marseille Univ, IRD, INSERM, SESSTIM, Marseille, France
| | - Cheikh Sokhna
- UMR VITROME, Campus International IRD-UCAD de l'IRD, Dakar, Sénégal
| | - Jean Gaudart
- Aix Marseille Univ, APHM, INSERM, IRD, SESSTIM, Hop Timone, BioSTIC, Biostatistic & ICT, Marseille, France
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Dieng S, Michel P, Guindo A, Sallah K, Ba EH, Cissé B, Carrieri MP, Sokhna C, Milligan P, Gaudart J. Application of Functional Data Analysis to Identify Patterns of Malaria Incidence, to Guide Targeted Control Strategies. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17114168. [PMID: 32545302 PMCID: PMC7312547 DOI: 10.3390/ijerph17114168] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 06/05/2020] [Accepted: 06/06/2020] [Indexed: 11/16/2022]
Abstract
We introduce an approach based on functional data analysis to identify patterns of malaria incidence to guide effective targeting of malaria control in a seasonal transmission area. Using functional data method, a smooth function (functional data or curve) was fitted from the time series of observed malaria incidence for each of 575 villages in west-central Senegal from 2008 to 2012. These 575 smooth functions were classified using hierarchical clustering (Ward’s method), and several different dissimilarity measures. Validity indices were used to determine the number of distinct temporal patterns of malaria incidence. Epidemiological indicators characterizing the resulting malaria incidence patterns were determined from the velocity and acceleration of their incidences over time. We identified three distinct patterns of malaria incidence: high-, intermediate-, and low-incidence patterns in respectively 2% (12/575), 17% (97/575), and 81% (466/575) of villages. Epidemiological indicators characterizing the fluctuations in malaria incidence showed that seasonal outbreaks started later, and ended earlier, in the low-incidence pattern. Functional data analysis can be used to identify patterns of malaria incidence, by considering their temporal dynamics. Epidemiological indicators derived from their velocities and accelerations, may guide to target control measures according to patterns.
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Affiliation(s)
- Sokhna Dieng
- Sciences Economiques et Sociales de la Santé et Traitement de de l'Information Médicale (SESSTIM), Institut de Recherche pour le Développement (IRD), Institut National de la Santé et de la Recherche médicale (INSERM), Aix Marseille Université, 13005 Marseille, France
| | - Pierre Michel
- Aix Marseille School of Economics (AMSE), Centrale Marseille, Ecoles des Hautes Etudes en Sciences Sociales (EHESS), Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université, 13001 Marseille, France
| | - Abdoulaye Guindo
- Sciences Economiques et Sociales de la Santé et Traitement de de l'Information Médicale (SESSTIM), Institut de Recherche pour le Développement (IRD), Institut National de la Santé et de la Recherche médicale (INSERM), Aix Marseille Université, 13005 Marseille, France
- Mère et Enfant face aux Infections Tropicales (MERIT), Institut de Recherche pour le Développement (IRD), Université Paris 5, 75006 Paris, France
| | - Kankoe Sallah
- Sciences Economiques et Sociales de la Santé et Traitement de de l'Information Médicale (SESSTIM), Institut de Recherche pour le Développement (IRD), Institut National de la Santé et de la Recherche médicale (INSERM), Aix Marseille Université, 13005 Marseille, France
- Unité de Recherche Clinique Paris Nord Val de Seine (PNVS), Hôpital Bichat, Assistance Publique-Hôpitaux de Paris (AP-HP), 75018 Paris, France
| | - El-Hadj Ba
- Unité Mixte de Recherche (UMR), Vecteurs-Infections Tropicales et Méditerranéennes (VITROME), Campus International Institut de Recherche pour le Développement-Université Cheikh Anta Diop (IRD-UCAD) de l'IRD, Dakar CP 18524, Senegal
| | - Badara Cissé
- Institut de Recherche en Santé, de Surveillance Épidémiologique et de Formation (IRESSEF) Diamniadio, Dakar BP 7325, Senegal
| | - Maria Patrizia Carrieri
- Sciences Economiques et Sociales de la Santé et Traitement de de l'Information Médicale (SESSTIM), Institut de Recherche pour le Développement (IRD), Institut National de la Santé et de la Recherche médicale (INSERM), Aix Marseille Université, 13005 Marseille, France
| | - Cheikh Sokhna
- Unité Mixte de Recherche (UMR), Vecteurs-Infections Tropicales et Méditerranéennes (VITROME), Campus International Institut de Recherche pour le Développement-Université Cheikh Anta Diop (IRD-UCAD) de l'IRD, Dakar CP 18524, Senegal
| | - Paul Milligan
- London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
| | - Jean Gaudart
- Aix Marseille Université, Assistance Publique-Hôpitaux de Marseille(APHM), INSERM, IRD, SESSTIM, Hop Timone, BioSTIC, Biostatistic and ICT, 13005 Marseille, France
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Sougoufara S, Ottih EC, Tripet F. The need for new vector control approaches targeting outdoor biting Anopheline malaria vector communities. Parasit Vectors 2020; 13:295. [PMID: 32522290 PMCID: PMC7285743 DOI: 10.1186/s13071-020-04170-7] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 06/04/2020] [Indexed: 12/13/2022] Open
Abstract
Since the implementation of Roll Back Malaria, the widespread use of insecticide-treated nets (ITNs) and indoor residual spraying (IRS) is thought to have played a major part in the decrease in mortality and morbidity achieved in malaria-endemic regions. In the past decade, resistance to major classes of insecticides recommended for public health has spread across many malaria vector populations. Increasingly, malaria vectors are also showing changes in vector behaviour in response to current indoor chemical vector control interventions. Changes in the time of biting and proportion of indoor biting of major vectors, as well as changes in the species composition of mosquito communities threaten the progress made to control malaria transmission. Outdoor biting mosquito populations contribute to malaria transmission in many parts of sub-Saharan Africa and pose new challenges as they cannot be reliably monitored or controlled using conventional tools. Here, we review existing and novel approaches that may be used to target outdoor communities of malaria vectors. We conclude that scalable tools designed specifically for the control and monitoring of outdoor biting and resting malaria vectors with increasingly complex and dynamic responses to intensifying malaria control interventions are urgently needed. These are crucial for integrated vector management programmes designed to challenge current and future vector populations.
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Affiliation(s)
- Seynabou Sougoufara
- Centre of Applied Entomology and Parasitology, School of Life Sciences, Keele University, Staffordshire, UK
| | - Emmanuel Chinweuba Ottih
- Centre of Applied Entomology and Parasitology, School of Life Sciences, Keele University, Staffordshire, UK
| | - Frederic Tripet
- Centre of Applied Entomology and Parasitology, School of Life Sciences, Keele University, Staffordshire, UK
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Old and Recent Advances in Life Cycle, Pathogenesis, Diagnosis, Prevention, and Treatment of Malaria Including Perspectives in Ethiopia. ScientificWorldJournal 2020. [DOI: 10.1155/2020/1295381] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Malaria, caused by apicomplexan parasite, is an old disease and continues to be a major public health threat in many countries. This article aims to present different aspects of malaria including causes, pathogenesis, prevention, and treatment in an articulate and comprehensive manner. Six Plasmodium species are recognized as the etiology of human malaria, of which Plasmodium falciparum is popular in East and Southern Africa. Malaria is transmitted mainly through Anopheles gambiae and Anopheles funestus, the two most effective malaria vectors in the world. Half of the world’s population is at risk for malaria infection. Globally, the morbidity and mortality rates of malaria have become decreased even though few reports in Ethiopia showed high prevalence of malaria. The malaria parasite has a complex life cycle that takes place both inside the mosquito and human beings. Generally, diagnosis of malaria is classified into clinical and parasitological diagnoses. Lack of clear understanding on the overall biology of Plasmodium has created a challenge in an effort to develop new drugs, vaccines, and preventive methods against malaria. However, three types of vaccines and a lot of novel compounds are under perclinical and clinical studies that are triggered by the occurrence of resistance among commonly used drugs and insecticides. Antiadhesion adjunctive therapies are also under investigation in the laboratory. In addition to previously known targets for diagnostic tool, vaccine and drug discovery scientists from all corner of the world are in search of new targets and chemical entities.
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Billingsley P, Binka F, Chaccour C, Foy B, Gold S, Gonzalez-Silva M, Jacobson J, Jagoe G, Jones C, Kachur P, Kobylinski K, Last A, Lavery JV, Mabey D, Mboera D, Mbogo C, Mendez-Lopez A, Rabinovich NR, Rees S, Richards F, Rist C, Rockwood J, Ruiz-Castillo P, Sattabongkot J, Saute F, Slater H, Steer A, Xia K, Zullinger R. A Roadmap for the Development of Ivermectin as a Complementary Malaria Vector Control Tool. Am J Trop Med Hyg 2020; 102:3-24. [PMID: 31971144 PMCID: PMC7008306 DOI: 10.4269/ajtmh.19-0620] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 10/22/2019] [Indexed: 12/14/2022] Open
Abstract
In the context of stalling progress against malaria, resistance of mosquitoes to insecticides, and residual transmission, mass drug administration (MDA) of ivermectin, an endectocide used for neglected tropical diseases (NTDs), has emerged as a promising complementary vector control method. Ivermectin reduces the life span of Anopheles mosquitoes that feed on treated humans and/or livestock, potentially decreasing malaria parasite transmission when administered at the community level. Following the publication by WHO of the preferred product characteristics for endectocides as vector control tools, this roadmap provides a comprehensive view of processes needed to make ivermectin available as a vector control tool by 2024 with a completely novel mechanism of action. The roadmap covers various aspects, which include 1) the definition of optimal dosage/regimens for ivermectin MDA in both humans and livestock, 2) the risk of resistance to the drug and environmental impact, 3) ethical issues, 4) political and community engagement, 5) translation of evidence into policy, and 6) operational aspects of large-scale deployment of the drug, all in the context of a drug given as a prevention tool acting at the community level. The roadmap reflects the insights of a multidisciplinary group of global health experts who worked together to elucidate the path to inclusion of ivermectin in the toolbox against malaria, to address residual transmission, counteract insecticide resistance, and contribute to the end of this deadly disease.
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Affiliation(s)
| | - Fred Binka
- University of Health and Allied Sciences
| | | | | | | | | | | | | | | | | | | | - Anna Last
- London School of Hygiene and Tropical Medicine
| | | | - David Mabey
- London School of Hygiene and Tropical Medicine
| | | | | | | | | | | | | | - Cassidy Rist
- Virginia-Maryland College of Veterinary Medicine at Virginia Tech
| | | | | | | | | | | | | | - Kang Xia
- School of Plant and Environmental Sciences, Virginia Tech
| | - Rose Zullinger
- US President’s Malaria Initiative/US Centers for Disease Control and Prevention
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Ivermectin as a novel complementary malaria control tool to reduce incidence and prevalence: a modelling study. THE LANCET. INFECTIOUS DISEASES 2020; 20:498-508. [PMID: 31948767 DOI: 10.1016/s1473-3099(19)30633-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 09/30/2019] [Accepted: 10/21/2019] [Indexed: 11/22/2022]
Abstract
BACKGROUND Ivermectin is a potential new vector control tool to reduce malaria transmission. Mosquitoes feeding on a bloodmeal containing ivermectin have a reduced lifespan, meaning they are less likely to live long enough to complete sporogony and become infectious. We aimed to estimate the effect of ivermectin on malaria transmission in various scenarios of use. METHODS We validated an existing population-level mathematical model of the effect of ivermectin mass drug administration (MDA) on the mosquito population and malaria transmission against two datasets: clinical data from a cluster- randomised trial done in Burkina Faso in 2015 wherein ivermectin was given to individuals taller than 90 cm and entomological data from a study of mosquito outcomes after ivermectin MDA for onchocerciasis or lymphatic filariasis in Burkina Faso, Senegal, and Liberia between 2008 and 2013. We extended the existing model to include a range of complementary malaria interventions (seasonal malaria chemoprevention and MDA with dihydroartemisinin-piperaquine) and to incorporate new data on higher doses of ivermectin with a longer mosquitocidal effect. We consider two ivermectin regimens: a single dose of 400 μg/kg (1 × 400 μg/kg) and three consecutive daily doses of 300 μg/kg per day (3 × 300 μg/kg). We simulated the effect of these two doses in a range of usage scenarios in different transmission settings (highly seasonal, seasonal, and perennial). We report percentage reductions in clinical incidence and slide prevalence. FINDINGS We estimate that MDA with ivermectin will reduce prevalence and incidence and is most effective in areas with highly seasonal transmission. In a highly seasonal moderate transmission setting, three rounds of ivermectin only MDA at 3 × 300 μg/kg (rounds spaced 1 month apart) and 70% coverage is predicted to reduce clinical incidence by 71% and prevalence by 34%. We predict that adding ivermectin MDA to seasonal malaria chemoprevention in this setting would reduce clinical incidence by an additional 77% in children younger than 5 years compared with seasonal malaria chemoprevention alone; adding ivermectin MDA to MDA with dihydroartemisinin-piperaquine in this setting would reduce incidence by an additional 75% and prevalence by an additional 64% (all ages) compared with MDA with dihydroartemisinin-piperaquine alone. INTERPRETATION Our modelling predictions suggest that ivermectin could be a valuable addition to the malaria control toolbox, both in areas with persistently high transmission where existing interventions are insufficient and in areas approaching elimination to prevent resurgence. FUNDING Imperial College Junior Research Fellowship.
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Kobylinski KC, Jittamala P, Hanboonkunupakarn B, Pukrittayakamee S, Pantuwatana K, Phasomkusolsil S, Davidson SA, Winterberg M, Hoglund RM, Mukaka M, van der Pluijm RW, Dondorp A, Day NPJ, White NJ, Tarning J. Safety, Pharmacokinetics, and Mosquito-Lethal Effects of Ivermectin in Combination With Dihydroartemisinin-Piperaquine and Primaquine in Healthy Adult Thai Subjects. Clin Pharmacol Ther 2019; 107:1221-1230. [PMID: 31697848 PMCID: PMC7285759 DOI: 10.1002/cpt.1716] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 10/15/2019] [Indexed: 12/30/2022]
Abstract
Mass administration of antimalarial drugs and ivermectin are being considered as potential accelerators of malaria elimination. The safety, tolerability, pharmacokinetics, and mosquito‐lethal effects of combinations of ivermectin, dihydroartemisinin‐piperaquine, and primaquine were evaluated. Coadministration of ivermectin and dihydroartemisinin‐piperaquine resulted in increased ivermectin concentrations with corresponding increases in mosquito‐lethal effect across all subjects. Exposure to piperaquine was also increased when coadministered with ivermectin, but electrocardiograph QT‐interval prolongation was not increased. One subject had transiently impaired liver function. Ivermectin mosquito‐lethal effect was greater than predicted previously against the major Southeast Asian malaria vectors. Both Anopheles dirus and Anopheles minimus mosquito mortality was increased substantially (20‐fold and 35‐fold increase, respectively) when feeding on volunteer blood after ivermectin administration compared with in vitro ivermectin‐spiked blood. This suggests the presence of ivermectin metabolites that impart mosquito‐lethal effects. Further studies of this combined approach to accelerate malaria elimination are warranted.
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Affiliation(s)
- Kevin C Kobylinski
- Department of Entomology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand.,Entomology Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
| | - Podjanee Jittamala
- Department of Tropical Hygiene, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Borimas Hanboonkunupakarn
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Sasithon Pukrittayakamee
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,The Royal Society of Thailand, Dusit, Bangkok, Thailand
| | - Kanchana Pantuwatana
- Department of Entomology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Siriporn Phasomkusolsil
- Department of Entomology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Silas A Davidson
- Department of Entomology, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand.,Entomology Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
| | - Markus Winterberg
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Richard M Hoglund
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Mavuto Mukaka
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Rob W van der Pluijm
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Arjen Dondorp
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Nicholas P J Day
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Nicholas J White
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Joel Tarning
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.,Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
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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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Mekuriaw W, Balkew M, Messenger LA, Yewhalaw D, Woyessa A, Massebo F. The effect of ivermectin ® on fertility, fecundity and mortality of Anopheles arabiensis fed on treated men in Ethiopia. Malar J 2019; 18:357. [PMID: 31703736 PMCID: PMC6842263 DOI: 10.1186/s12936-019-2988-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 10/24/2019] [Indexed: 12/13/2022] Open
Abstract
Background Insecticide resistance is a growing threat to malaria vector control. Ivermectin, either administered to humans or animals, may represent an alternate strategy to reduce resistant mosquito populations. The aim of this study was to assess the residual or delayed effect of administering a single oral dose of ivermectin to humans on the survival, fecundity and fertility of Anopheles arabiensis in Ethiopia. Methods Six male volunteers aged 25–40 years (weight range 64–72 kg) were recruited; four of them received a recommended single oral dose of 12 mg ivermectin and the other two individuals were untreated controls. A fully susceptible insectary colony of An. arabiensis was fed on treated and control participants at 1, 4, 7, 10 and 13 days post ivermectin-administration. Daily mosquito mortality was recorded for 5 days. An. arabiensis fecundity and fertility were measured from day 7 post treatment, by dissection to examine the number of eggs per mosquito, and by observing larval hatching rates, respectively. Results Ivermectin treatment induced significantly higher An. arabiensis mortality on days 1 and 4, compared to untreated controls (p = 0.02 and p < 0.001, respectively). However, this effect had declined by day 7, with no significant difference in mortality between treated and control groups (p = 0.06). The mean survival time of mosquitoes fed on day 1 was 2.1 days, while those fed on day 4 survived 4.0 days. Mosquitoes fed on the treatment group at day 7 and 10 produced significantly lower numbers of eggs compared to the untreated controls (p < 0.001 and p = 0.04, respectively). An. arabiensis fed on day 7 on treated men also had lower larval hatching rates than mosquitoes fed on days 10 and 13 (p = 0.003 and p = 0.001, respectively). Conclusion A single oral dose of ivermectin given to humans can induce mortality and reduce survivorship of An. arabiensis for 7 days after treatment. Ivermectin also had a delayed effect on fecundity of An. arabiensis that took bloodmeals from treated individuals on day 7 and 10. Additional studies are warranted using wild, insecticide-resistant mosquito populations, to confirm findings and a phase III evaluation among community members in Ethiopia is needed to determine the impact of ivermectin on malaria transmission.
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Affiliation(s)
- Wondemeneh Mekuriaw
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia. .,Department of Biology, Arba Minch University, Arba Minch, Ethiopia.
| | - Meshesha Balkew
- Abt Associates, PMI Vectorlink Project in Ethiopia, Addis Ababa, Ethiopia
| | - Louisa A Messenger
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, UK
| | - Delenasaw Yewhalaw
- Tropical and Infectious Disease Research Center, Jimma University, Jimma, Ethiopia.,Department of Medical Laboratory Sciences and Pathology, College of Health Sciences, Jimma University, Jimma, Ethiopia
| | - Adugna Woyessa
- Ethiopian Public Health Institute, Addis Ababa, Ethiopia
| | - Fekadu Massebo
- Department of Biology, Arba Minch University, Arba Minch, Ethiopia
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Atif M, Lynch JW, Keramidas A. The effects of insecticides on two splice variants of the glutamate-gated chloride channel receptor of the major malaria vector, Anopheles gambiae. Br J Pharmacol 2019; 177:175-187. [PMID: 31479507 DOI: 10.1111/bph.14855] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 08/18/2019] [Accepted: 08/27/2019] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE Between half to 1 million people die annually from malaria. Anopheles gambiae mosquitoes are major malaria vectors. Unfortunately, resistance has emerged to the agents currently used to control A. gambiae, creating a demand for novel control measures. The pentameric glutamate-gated chloride channel (GluCl) expressed in the muscle and nerve cells of these organisms are a potentially important biological target for malaria control. The pharmacological properties of Anophiline GluCl receptors are, however, largely unknown. Accordingly, we compared the efficacy of four insecticides (lindane, fipronil, picrotoxin, and ivermectin) on two A. gambiae GluCl receptor splice variants with the aim of providing a molecular basis for designing novel anti-malaria treatments. EXPERIMENTAL APPROACH The A. gambiae GluCl receptor b1 and c splice variants were expressed homomerically in Xenopus laevis oocytes and studied with electrophysiological techniques, using two-electrode voltage-clamp. KEY RESULTS The b1 and c GluCl receptors were activated with similar potencies by glutamate and ivermectin. Fipronil was more potent than picrotoxin and lindane at inhibiting glutamate- and ivermectin-gated currents. Importantly, b1 GluCl receptors exhibited reduced sensitivity to picrotoxin and lindane. They also recovered from these effects to a greater extent than c GluCl receptors CONCLUSIONS AND IMPLICATIONS: The two splice variant subunits exhibited differential sensitivities to multiple, structurally divergent insecticides, without accompanying changes in the sensitivity to the endogenous neurotransmitter, glutamate, implying that drug resistance may be caused by alterations in relative subunit expression levels, without affecting physiological function. Our results strongly suggest that it should be feasible to develop novel subunit-specific pharmacological agents.
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Affiliation(s)
- Mohammed Atif
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Joseph W Lynch
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Angelo Keramidas
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
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Noskov YA, Polenogova OV, Yaroslavtseva ON, Belevich OE, Yurchenko YA, Chertkova EA, Kryukova NA, Kryukov VY, Glupov VV. Combined effect of the entomopathogenic fungus Metarhizium robertsii and avermectins on the survival and immune response of Aedes aegypti larvae. PeerJ 2019; 7:e7931. [PMID: 31667017 PMCID: PMC6816395 DOI: 10.7717/peerj.7931] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 09/23/2019] [Indexed: 12/18/2022] Open
Abstract
Combination of insect pathogenic fungi and microbial metabolites is a prospective method for mosquito control. The effect of the entomopathogenic fungus Metarhizium robertsii J.F. Bischoff, S.A. Rehner & Humber and avermectins on the survival and physiological parameters of Aedes aegypti (Linnaeus, 1762) larvae (dopamine concentration, glutathione S-transferase (GST), nonspecific esterases (EST), acid proteases, lysozyme-like, phenoloxidase (PO) activities) was studied. It is shown that the combination of these agents leads to a synergistic effect on mosquito mortality. Colonization of Ae. aegypti larvae by hyphal bodies following water inoculation with conidia is shown for the first time. The larvae affected by fungi are characterized by a decrease in PO and dopamine levels. In the initial stages of toxicosis and/or fungal infection (12 h posttreatment), increases in the activity of insect detoxifying enzymes (GST and EST) and acid proteases are observed after monotreatments, and these increases are suppressed after combined treatment with the fungus and avermectins. Lysozyme-like activity is also most strongly suppressed under combined treatment with the fungus and avermectins in the early stages posttreatment (12 h). Forty-eight hours posttreatment, we observe increases in GST, EST, acid proteases, and lysozyme-like activities under the influence of the fungus and/or avermectins. The larvae affected by avermectins accumulate lower levels of conidia than avermectin-free larvae. On the other hand, a burst of bacterial CFUs is observed under treatment with both the fungus and avermectins. We suggest that disturbance of the responses of the immune and detoxifying systems under the combined treatment and the development of opportunistic bacteria may be among the causes of the synergistic effect.
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Affiliation(s)
- Yuriy A Noskov
- Institute of Systematics and Ecology of Animals, Siberian Branch of Russian Academy of Sciences, Novosibirsk, Russia.,Tomsk State University, Tomsk, Russia
| | - Olga V Polenogova
- Institute of Systematics and Ecology of Animals, Siberian Branch of Russian Academy of Sciences, Novosibirsk, Russia
| | - Olga N Yaroslavtseva
- Institute of Systematics and Ecology of Animals, Siberian Branch of Russian Academy of Sciences, Novosibirsk, Russia
| | - Olga E Belevich
- Institute of Systematics and Ecology of Animals, Siberian Branch of Russian Academy of Sciences, Novosibirsk, Russia
| | - Yuriy A Yurchenko
- Institute of Systematics and Ecology of Animals, Siberian Branch of Russian Academy of Sciences, Novosibirsk, Russia
| | - Ekaterina A Chertkova
- Institute of Systematics and Ecology of Animals, Siberian Branch of Russian Academy of Sciences, Novosibirsk, Russia
| | - Natalya A Kryukova
- Institute of Systematics and Ecology of Animals, Siberian Branch of Russian Academy of Sciences, Novosibirsk, Russia
| | - Vadim Yu Kryukov
- Institute of Systematics and Ecology of Animals, Siberian Branch of Russian Academy of Sciences, Novosibirsk, Russia
| | - Viktor V Glupov
- Institute of Systematics and Ecology of Animals, Siberian Branch of Russian Academy of Sciences, Novosibirsk, Russia
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Sequeira J, Louçã J, Mendes AM, Lind PG. Transition from endemic behavior to eradication of malaria due to combined drug therapies: An agent-model approach. J Theor Biol 2019; 484:110030. [PMID: 31568789 DOI: 10.1016/j.jtbi.2019.110030] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 09/14/2019] [Accepted: 09/26/2019] [Indexed: 01/05/2023]
Abstract
We introduce an agent-based model describing a susceptible-infectious-susceptible (SIS) system of humans and mosquitoes to predict malaria epidemiological scenarios in realistic biological conditions. Emphasis is given to the transition from endemic behavior to eradication of malaria transmission induced by combined drug therapies acting on both the gametocytemia reduction and on the selective mosquito mortality during parasite development in the mosquito. Our mathematical framework enables to uncover the critical values of the parameters characterizing the effect of each drug therapy. Moreover, our results provide quantitative evidence of what was up to now only partially assumed with empirical support: interventions combining gametocytemia reduction through the use of gametocidal drugs, with the selective action of ivermectin during parasite development in the mosquito, may actively promote disease eradication in the long run. In the agent model, the main properties of human-mosquito interactions are implemented as parameters and the model is validated by comparing simulations with real data of malaria incidence collected in the endemic malaria region of Chimoio in Mozambique. Finally, we discuss our findings in light of current drug administration strategies for malaria prevention, which may interfere with human-to-mosquito transmission process.
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Affiliation(s)
- João Sequeira
- Instituto Universitário de Lisboa (ISCTE-IUL), ISTAR-IUL, Av. das Forças Armadas, Lisboa 1649-026, Portugal; Hospital Santa Cruz, Av. Prof. Dr. Reinaldo dos Santos, Carnaxide 2790-134, Portugal
| | - Jorge Louçã
- Instituto Universitário de Lisboa (ISCTE-IUL), ISTAR-IUL, Av. das Forças Armadas, Lisboa 1649-026, Portugal
| | - António M Mendes
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Av. Prof. Egas Moniz, Lisboa 1649-028, Portugal
| | - Pedro G Lind
- Instituto Universitário de Lisboa (ISCTE-IUL), ISTAR-IUL, Av. das Forças Armadas, Lisboa 1649-026, Portugal; Department of Computer Science, OsloMet - Oslo Metropolitan University, P.O. Box 4 St. Olavs plass, Oslo N-0130, Norway.
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Ivermectin Impairs the Development of Sexual and Asexual Stages of Plasmodium falciparum In Vitro. Antimicrob Agents Chemother 2019; 63:AAC.00085-19. [PMID: 31109978 DOI: 10.1128/aac.00085-19] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 05/09/2019] [Indexed: 12/11/2022] Open
Abstract
Ivermectin is the drug of choice for many parasitic infections, with more than one billion doses being distributed in onchocerciasis programs. The drug has been put into focus recently by the malaria community because of its potential to kill blood-sucking mosquitoes, thereby reducing malaria transmission. However, the activity of ivermectin against the malaria parasite itself has been only partly investigated. This study aimed to investigate the in vitro activity of ivermectin against asexual and sexual stages of Plasmodium falciparum Both asexual and late-stage gametocytes were incubated with ivermectin and control drugs in vitro The growth-inhibiting effects were assessed for asexual stages of different Plasmodium falciparum laboratory strains and culture-adapted clinical isolates using the histidine-rich protein 2 enzyme-linked immunosorbent assay technique. The effect against stage IV/V gametocytes was evaluated based on ATP quantification. Ivermectin showed activities at nanomolar concentrations against asexual stages (50% inhibitory concentration of ∼100 nM) and stage IV/V gametocytes (500 nM) of P. falciparum Stage-specific assays suggested that ivermectin arrests the parasite cycle at the trophozoite stage. Ivermectin might add a feature to its "wonder drug" properties with activity against asexual stages of the malaria parasite Plasmodium falciparum The observed activities might be difficult to reach with current regimens but will be more relevant with future high-dose regimens under investigation. Further studies should be performed to confirm these results in vitro and in vivo.
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Foy BD, Alout H, Seaman JA, Rao S, Magalhaes T, Wade M, Parikh S, Soma DD, Sagna AB, Fournet F, Slater HC, Bougma R, Drabo F, Diabaté A, Coulidiaty AGV, Rouamba N, Dabiré RK. Efficacy and risk of harms of repeat ivermectin mass drug administrations for control of malaria (RIMDAMAL): a cluster-randomised trial. Lancet 2019; 393:1517-1526. [PMID: 30878222 PMCID: PMC6459982 DOI: 10.1016/s0140-6736(18)32321-3] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 09/11/2018] [Accepted: 09/13/2018] [Indexed: 10/27/2022]
Abstract
BACKGROUND Ivermectin is widely used in mass drug administrations for controlling neglected parasitic diseases, and can be lethal to malaria vectors that bite treated humans. Therefore, it could be a new tool to reduce plasmodium transmission. We tested the hypothesis that frequently repeated mass administrations of ivermectin to village residents would reduce clinical malaria episodes in children and would be well tolerated with minimal harms. METHODS We invited villages (clusters) in Burkina Faso to participate in a single-blind (outcomes assessor), parallel-assignment, two-arm, cluster-randomised trial over the 2015 rainy season. Villages were assigned (1:1) by random draw to either the intervention group or the control group. In both groups, all eligible participants who consented to the treatment and were at least 90 cm in height received single oral doses of ivermectin (150-200 μg/kg) and albendazole (400 mg), and those in the intervention group received five further doses of ivermectin alone at 3-week intervals thereafter over the 18-week treatment phase. The primary outcome was cumulative incidence of uncomplicated malaria episodes over 18 weeks (analysed on a cluster intention-to-treat basis) in an active case detection cohort of children aged 5 years or younger living in the study villages. This trial is registered with ClinicalTrials.gov, number NCT02509481. FINDINGS Eight villages agreed to participate, and four were randomly assigned to each group. 2712 participants (1333 [49%] males and 1379 [51%] females; median age 15 years [IQR 6-34]), including 590 children aged 5 years or younger, provided consent and were enrolled between May 22 and July 20, 2015 (except for 77 participants enrolled after these dates because of unavailability before the first mass drug administration, travel into the village during the trial, or birth), with 1447 enrolled into the intervention group and 1265 into the control group. 330 (23%) participants in the intervention group and 233 (18%) in the control group met the exclusion criteria for mass drug administration. Most children in the active case detection cohort were not treated because of height restrictions. 14 (4%) children in the intervention group and 10 (4%) in the control group were lost to follow-up. Cumulative malaria incidence was reduced in the intervention group (648 episodes among 327 children; estimated mean 2·00 episodes per child) compared with the control group (647 episodes among 263 children; 2·49 episodes per child; risk difference -0·49 [95% CI -0·79 to -0·21], p=0·0009, adjusted for sex and clustering). The risk of adverse events among all participants did not differ between groups (45 events [3%] among 1447 participants in the intervention group vs 24 events [2%] among 1265 in the control group; risk ratio 1·63 [1·01 to 2·67]; risk difference 1·21 [0·04 to 2·38], p=0·060), and no adverse reactions were reported. INTERPRETATION Frequently repeated mass administrations of ivermectin during the malaria transmission season can reduce malaria episodes among children without significantly increasing harms in the populace. FUNDING Bill & Melinda Gates Foundation.
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Affiliation(s)
- Brian D Foy
- Arthropod-borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, USA.
| | - Haoues Alout
- Arthropod-borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Jonathan A Seaman
- Arthropod-borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Sangeeta Rao
- Department of Clinical Sciences, Colorado State University, Fort Collins, CO, USA
| | - Tereza Magalhaes
- Arthropod-borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, USA
| | - Martina Wade
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
| | - Sunil Parikh
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
| | - Dieudonné D Soma
- Institute of Research in Health Sciences, Western Regional Direction, National Center for Scientific and Technological Research, Bobo-Dioulasso, Burkina Faso; International Mixed Laboratory on Vector Diseases, Bobo-Dioulasso, Burkina Faso
| | - André B Sagna
- International Mixed Laboratory on Vector Diseases, Bobo-Dioulasso, Burkina Faso; Research Institute for Development, Infectious Diseases, and Vectors: Ecology, Genetics, Evolution and Control, National Centre for Scientific Research, University of Montpellier, Montpellier, France
| | - Florence Fournet
- International Mixed Laboratory on Vector Diseases, Bobo-Dioulasso, Burkina Faso; Research Institute for Development, Infectious Diseases, and Vectors: Ecology, Genetics, Evolution and Control, National Centre for Scientific Research, University of Montpellier, Montpellier, France
| | - Hannah C Slater
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Roland Bougma
- National Program for the Fight against Neglected Tropical Diseases, Department of Disease Control, Ministry of Health, Ouagadougou, Burkina Faso
| | - François Drabo
- National Program for the Fight against Neglected Tropical Diseases, Department of Disease Control, Ministry of Health, Ouagadougou, Burkina Faso
| | - Abdoulaye Diabaté
- Institute of Research in Health Sciences, Western Regional Direction, National Center for Scientific and Technological Research, Bobo-Dioulasso, Burkina Faso; International Mixed Laboratory on Vector Diseases, Bobo-Dioulasso, Burkina Faso
| | | | - Nöel Rouamba
- Institute of Research in Health Sciences, Western Regional Direction, National Center for Scientific and Technological Research, Bobo-Dioulasso, Burkina Faso
| | - Roch K Dabiré
- Institute of Research in Health Sciences, Western Regional Direction, National Center for Scientific and Technological Research, Bobo-Dioulasso, Burkina Faso; International Mixed Laboratory on Vector Diseases, Bobo-Dioulasso, Burkina Faso
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47
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Nguyen C, Gray M, Burton TA, Foy SL, Foster JR, Gendernalik AL, Rückert C, Alout H, Young MC, Boze B, Ebel GD, Clapsaddle B, Foy BD. Evaluation of a novel West Nile virus transmission control strategy that targets Culex tarsalis with endectocide-containing blood meals. PLoS Negl Trop Dis 2019; 13:e0007210. [PMID: 30845250 PMCID: PMC6424467 DOI: 10.1371/journal.pntd.0007210] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 03/19/2019] [Accepted: 02/04/2019] [Indexed: 11/27/2022] Open
Abstract
Control of arbovirus transmission remains focused on vector control through application of insecticides directly to the environment. However, these insecticide applications are often reactive interventions that can be poorly-targeted, inadequate for localized control during outbreaks, and opposed due to environmental and toxicity concerns. In this study, we developed endectocide-treated feed as a systemic endectocide for birds to target blood feeding Culex tarsalis, the primary West Nile virus (WNV) bridge vector in the western United States, and conducted preliminary tests on the effects of deploying this feed in the field. In lab tests, ivermectin (IVM) was the most effective endectocide tested against Cx. tarsalis and WNV-infection did not influence mosquito mortality from IVM. Chickens and wild Eurasian collared doves exhibited no signs of toxicity when fed solely on bird feed treated with concentrations up to 200 mg IVM/kg of diet, and significantly more Cx. tarsalis that blood fed on these birds died (greater than 80% mortality) compared to controls (less than 25% mortality). Mosquito mortality following blood feeding correlated with IVM serum concentrations at the time of blood feeding, which dropped rapidly after the withdrawal of treated feed. Preliminary field testing over one WNV season in Fort Collins, Colorado demonstrated that nearly all birds captured around treated bird feeders had detectable levels of IVM in their blood. However, entomological data showed that WNV transmission was non-significantly reduced around treated bird feeders. With further development, deployment of ivermectin-treated bird feed might be an effective, localized WNV transmission control tool. West Nile virus (WNV) is a mosquito-borne virus that causes significant disease and death every year in humans, domesticated animals, and wildlife. Control of WNV transmission is focused on controlling the mosquito vector through applications of insecticides directly to the environment. In this study, we evaluate a novel control strategy for WNV transmission by targeting the main mosquito bridge vector in the Great Plains region, Culex tarsalis, through its blood feeding behavior. Because Culex tarsalis favor taking blood meals from particular bird species, our strategy aims to target these bird species with endectocide-treated bird feed that will result in lethal blood meals for Cx. tarsalis. In this study, we developed a safe and effective formulation of ivermectin-treated diet that resulted in increased mortality for Cx. tarsalis blood fed on birds consuming this treated diet as compared to mosquitoes feeding on control birds. We also conducted a pilot field trial in Fort Collins, Colorado to test this strategy in a natural transmission cycle, which demonstrated promising results.
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Affiliation(s)
- Chilinh Nguyen
- Arthropod-borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States of America
- * E-mail:
| | - Meg Gray
- Arthropod-borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States of America
| | - Timothy A. Burton
- Arthropod-borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States of America
| | - Soleil L. Foy
- Arthropod-borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States of America
| | - John R. Foster
- Arthropod-borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States of America
| | - Alex Lazr Gendernalik
- Arthropod-borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States of America
| | - Claudia Rückert
- Arthropod-borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States of America
| | | | - Michael C. Young
- Arthropod-borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States of America
| | - Broox Boze
- Vector Disease Control International, Little Rock, AR, United States of America
| | - Gregory D. Ebel
- Arthropod-borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States of America
| | | | - Brian D. Foy
- Arthropod-borne and Infectious Diseases Laboratory, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States of America
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48
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Gari T, Lindtjørn B. Reshaping the vector control strategy for malaria elimination in Ethiopia in the context of current evidence and new tools: opportunities and challenges. Malar J 2018; 17:454. [PMID: 30518395 PMCID: PMC6282332 DOI: 10.1186/s12936-018-2607-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 12/01/2018] [Indexed: 12/20/2022] Open
Abstract
The core vector control measures, long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS), reduce the risk of malaria infection by targeting indoor biting mosquitoes. These two interventions are found to be effective in malaria control, but not sufficient to eliminate malaria. The main challenges with LLINs and IRS are insecticide resistance, misuse of the interventions, host behaviour, such as staying out-door during early night or sleeping outdoor without using protective measures, and vector behaviour including feeding on bovine blood, outdoor biting and outdoor resting. Therefore, for complete interruption of malaria transmission in a defined area there is a need to consider a variety of interventions that can help prevent out-door as well as indoor malaria transmission. In Ethiopia, to achieve the malaria elimination goal, a mix of vector control tools, such as intensifying the use of LLINs and IRS, and supplemented by use of ivermectin administration, zooprophylaxis, odour-baited mosquito trapping, improving housing and larva control measures tailored to the local situation of malaria transmission, may be needed.
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Affiliation(s)
- Taye Gari
- School of Public Health, College of Medicine and Health Sciences, Hawassa University, Hawassa, Ethiopia.
| | - Bernt Lindtjørn
- Centre for International Health, University of Bergen, Bergen, Norway
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49
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Gomez SA, Chapman LAC, Dilger E, Courtenay O, Picado A. Estimating the efficacy of community-wide use of systemic insecticides in dogs to control zoonotic visceral leishmaniasis: A modelling study in a Brazilian scenario. PLoS Negl Trop Dis 2018; 12:e0006797. [PMID: 30222756 PMCID: PMC6160230 DOI: 10.1371/journal.pntd.0006797] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 09/27/2018] [Accepted: 08/28/2018] [Indexed: 12/31/2022] Open
Abstract
Systemic insecticides in dogs have been suggested as a public health intervention to prevent human cases of Zoonotic Visceral Leishmaniasis (ZVL). But, currently there are no systemic insecticides for dogs registered against zoo-anthropophilic pool blood feeding phlebotomine flies. We predict the impact of community-wide use of systemic insecticide in dog populations as a public health measure to control transmission of Leishmania infantum to humans using a mathematical model. We developed a Susceptible-Exposed-Infected (SEI) compartmental model to describe L. infantum transmission dynamics in dogs, with a vectorial capacity term to represent transmission between L. infantum-hosting dogs via phlebotomine flies. For Infected (I) dogs two levels of infectiousness were modelled, high infectiousness and low infectiousness. Human incidence was estimated through its relationship to infection in the dog population. We evaluated outcomes from a wide range of scenarios comprising different combinations of initial insecticide efficacy, duration of insecticide efficacy over time, and proportion of the dog population treated (60%, 70% & 80%). The same reduction in human infection incidence can be achieved via different combinations of insecticide efficacy, duration and dog coverage. For example, a systemic insecticide with an initial efficacy of 80% and 6 months above 65% efficacy would require treating at least 70% of the dogs to reduce the human infection incidence by 50%. Sensitivity analysis showed that the model outcome was most sensitive to baseline values of phlebotomine fly daily survival rate and insecticide coverage. Community-wide use of systemic insecticides applied to the “L. infantum canine reservoir” can significantly reduce human incidence of L. infantum infection. The results of this mathematical model can help defining the insecticide target product profile and how the insecticide should be applied to maximise effectiveness. Zoonotic visceral leishmaniasis (ZVL) is a potentially deadly disease in humans caused by Leishmania infantum. This leishmania species can be delivered by pool blood feeding zoo-anthropophilic phlebotomine flies to several mammals, the dog population being recognized as the main reservoir. Transmission from infected dogs to humans is through the bite of female phlebotomine sand flies. The disease is endemic in several countries and Brazil has a high prevalence of cases with over 3000 ZVL cases reported per year. The main, inefficient and highly controversial, control measure in Brazil has been culling sero-positive dogs. The community-wide use of systemic insecticides in dogs could be an alternative to control L. infantum transmission from phlebotomine flies to humans. The rationale is that phlebotomine flies which sampled their blood meals from dogs treated with systemic insecticides would die reducing the risk of L. infantum transmission. To reduce the number of ZVL cases, a large proportion of dogs in the community should be treated and the systemic insecticide used should be effective in killing phlebotomine flies acting as vectors of L. infantum parasites for a significant amount of time. We used a mathematical model mimicking L. infantum transmission to show that this novel vector control strategy could be effective. We identified the combination of different key parameters (e.g. insecticide efficacy, duration and proportion of dogs treated) that could lead to a significant reduction of the risk of L. infantum infection in humans.
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Affiliation(s)
- Sonia A. Gomez
- ISGlobal-Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
- * E-mail: (AP); (SAG)
| | - Lloyd A. C. Chapman
- Department of Global Health and Development, London School of Hygiene and Tropical Medicine, London, United Kingdom
- School of Life Sciences, University of Warwick, Gibbet Hill Campus, Coventry, United Kingdom
| | - Erin Dilger
- School of Life Sciences, University of Warwick, Gibbet Hill Campus, Coventry, United Kingdom
| | - Orin Courtenay
- School of Life Sciences, University of Warwick, Gibbet Hill Campus, Coventry, United Kingdom
| | - Albert Picado
- ISGlobal-Hospital Clínic, Universitat de Barcelona, Barcelona, Spain
- * E-mail: (AP); (SAG)
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50
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Ng'habi K, Viana M, Matthiopoulos J, Lyimo I, Killeen G, Ferguson HM. Mesocosm experiments reveal the impact of mosquito control measures on malaria vector life history and population dynamics. Sci Rep 2018; 8:13949. [PMID: 30224714 PMCID: PMC6141522 DOI: 10.1038/s41598-018-31805-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 08/24/2018] [Indexed: 11/29/2022] Open
Abstract
The impact of control measures on mosquito vector fitness and demography is usually estimated from bioassays or indirect variables in the field. Whilst indicative, neither approach is sufficient to quantify the potentially complex response of mosquito populations to combined interventions. Here, large replicated mesocosms were used to measure the population-level response of the malaria vector Anopheles arabiensis to long-lasting insecticidal nets (LLINs) when used in isolation, or combined with insecticidal eave louvers (EL), or treatment of cattle with the endectocide Ivermectin (IM). State-space models (SSM) were fit to these experimental data, revealing that LLIN introduction reduced adult mosquito survival by 91% but allowed population persistence. ELs provided no additional benefit, but IM reduced mosquito fecundity by 59% and nearly eliminated all populations when combined with LLINs. This highlights the value of IM for integrated vector control, and mesocosm population experiments combined with SSM for identifying optimal combinations for vector population elimination.
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Affiliation(s)
- Kija Ng'habi
- Ifakara Health Institute, Environmental Health and Ecological Sciences, Ifakara, United Republic of Tanzania
- School of Health Sciences, University of Dar es Salaam, Dar es Salaam, Tanzania
| | - Mafalda Viana
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - Jason Matthiopoulos
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - Issa Lyimo
- Ifakara Health Institute, Environmental Health and Ecological Sciences, Ifakara, United Republic of Tanzania
| | - Gerry Killeen
- Ifakara Health Institute, Environmental Health and Ecological Sciences, Ifakara, United Republic of Tanzania
- Liverpool School of Tropical Medicine, Department of Vector Biology, Liverpool, United Kingdom
| | - Heather M Ferguson
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, United Kingdom.
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