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Furnival-Adams J, Kiuru C, Sagna AB, Mouline K, Maia M, Chaccour C. Ivermectin resistance mechanisms in ectoparasites: a scoping review. Parasitol Res 2024; 123:221. [PMID: 38787430 PMCID: PMC11126493 DOI: 10.1007/s00436-024-08223-z] [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: 03/05/2024] [Accepted: 04/24/2024] [Indexed: 05/25/2024]
Abstract
Ivermectin mass drug administration has been used for decades to target human and veterinary ectoparasites, and is currently being considered for use against malaria vectors. Although there have been few reports of resistance to date in human ectoparasites, we must anticipate the development of resistance in mosquitoes in the future. Hence, through this review, we mapped the existing evidence on ivermectin resistance mechanisms in human ectoparasites. A search was conducted on the 8th November 2023 through databases, PubMed, Web of Science, and Google Scholar, using terms related to ivermectin, human and veterinary ectoparasites, and resistance. Abstracts (5893) were screened by JFA and CK. Data on the study organism, the type of resistance, the analysis methods, and, where applicable, the gene loci of interest were extracted from the studies. Details of the methodology and results of each study were summarised narratively and in a table. Eighteen studies were identified describing ivermectin resistance in ectoparasites. Two studies described target site resistance; and 16 studies reported metabolic resistance and/or changes in efflux pump expression. The studies investigated genetic mutations in resistant organisms, detoxification, and efflux pump expression in resistant versus susceptible organisms, and the effect of synergists on mortality or detoxification enzyme/efflux pump transcription. To date, very few studies have been conducted examining the mechanisms of ivermectin resistance in ectoparasites, with only two on Anopheles spp. Of the existing studies, most examined detoxification and efflux pump gene expression, and only two studies in lice investigated target-site resistance. Further research in this field should be encouraged, to allow for close monitoring in ivermectin MDA programmes, and the development of resistance mitigation strategies.
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Affiliation(s)
- Joanna Furnival-Adams
- Barcelona Institute for Global Health (ISGlobal), Barcelona, Spain.
- Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona (UB), Barcelona, Spain.
| | - Caroline Kiuru
- Barcelona Institute for Global Health (ISGlobal), Barcelona, Spain
- Centro de Investigação Em Saúde de Manhiça (CISM), Maputo, Mozambique
| | | | - Karine Mouline
- MIVEGEC, University of Montpellier, IRD, CNRS, Montpellier, France
| | - Marta Maia
- Kenya Medical Research Institute, Wellcome Trust Research Programme, Kilifi, Kenya
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Carlos Chaccour
- Barcelona Institute for Global Health (ISGlobal), Barcelona, Spain
- CIBER de Enfermedades Infecciosas, Madrid, Spain
- Universidad de Navarra, Pamplona, Spain
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Shepherd-Gorringe MAM, Pettit MW, Hawkes FM. Lethal and sublethal impacts of membrane-fed ivermectin are concentration dependent in Anopheles coluzzii. Parasit Vectors 2024; 17:228. [PMID: 38755640 PMCID: PMC11100210 DOI: 10.1186/s13071-024-06287-5] [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: 01/26/2024] [Accepted: 04/18/2024] [Indexed: 05/18/2024] Open
Abstract
BACKGROUND Ivermectin is a well-tolerated anthelminthic drug with wide clinical and veterinary applications. It also has lethal and sublethal effects on mosquitoes. Mass drug administration with ivermectin has therefore been suggested as an innovative vector control tool in efforts to curb emerging insecticide resistance and reduce residual malaria transition. To support assessments of the feasibility and efficacy of current and future formulations of ivermectin for vector control, we sought to establish the relationship between ivermectin concentration and its lethal and sublethal impacts in a primary malaria vector. METHODS The in vitro effects of ivermectin on daily mortality and fecundity, measured by egg production, were assessed up to 14 days post-blood feed in a laboratory colony of Anopheles coluzzii. Mosquitoes were fed ivermectin in blood meals delivered by membrane feeding at one of six concentrations: 0 ng/ml (control), 10 ng/ml, 15 ng/ml, 25 ng/ml, 50 ng/ml, 75 ng/ml, and 100 ng/ml. RESULTS Ivermectin had a significant effect on mosquito survival in a concentration-dependent manner. The LC50 at 7 days was 19.7 ng/ml. The time to median mortality at ≥ 50 ng/ml was ≤ 4 days, compared to 9.6 days for control, and 6.3-7.6 days for ivermectin concentrations between 10 and 25 ng/ml. Fecundity was also affected; no oviposition was observed in surviving females from the two highest concentration treatment groups. While females exposed to 10 to 50 ng/ml of ivermectin did oviposit, significantly fewer did so in the 50 ng/ml treatment group compared to the control, and they also produced significantly fewer eggs. CONCLUSIONS Our results showed ivermectin reduced mosquito survival in a concentration-dependent manner and at ≥ 50 ng/ml significantly reduced fecundity in An. coluzzii. Results indicate that levels of ivermectin found in human blood following ingestion of a single 150-200 μg/kg dose would be sufficient to achieve 50% mortality across 7 days; however, fecundity in survivors is unlikely to be affected. At higher doses, a substantial impact on both survival and fecundity is likely. Treating human populations with ivermectin could be used as a supplementary malaria vector control method to kill mosquito populations and supress their reproduction; however strategies to safely maintain mosquitocidal blood levels of ivermectin against all Anopheles species require development.
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Affiliation(s)
- Monique A M Shepherd-Gorringe
- Medway Centre for Pharmaceutical Science, University of Greenwich, Chatham Maritime, Kent, ME4 4TB, UK.
- Natural Resources Institute, University of Greenwich at Medway, Chatham Maritime, Kent, ME4 4TB, UK.
| | - Marie W Pettit
- Medway Centre for Pharmaceutical Science, University of Greenwich, Chatham Maritime, Kent, ME4 4TB, UK
| | - Frances M Hawkes
- Natural Resources Institute, University of Greenwich at Medway, Chatham Maritime, Kent, ME4 4TB, UK
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Zeleke G, Duchateau L, Yewhalaw D, Suleman S, Devreese M. Pharmacokinetics of macrocyclic lactone endectocides in indigenous Zebu cattle and their insecticidal efficacy on Anopheles arabiensis. Exp Parasitol 2023; 253:108605. [PMID: 37659710 DOI: 10.1016/j.exppara.2023.108605] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 08/25/2023] [Accepted: 08/30/2023] [Indexed: 09/04/2023]
Abstract
Outdoor biting, outdoor resting, and early evening biting of Anopheles arabiensis is a challenge in current malaria control and elimination efforts in Africa. Zooprophylaxis using livestock treated with macrocyclic lactones is a novel approach to control zoophilic vectors. Therefore, the present study aimed to investigate the pharmacokinetics and insecticidal efficacy of ivermectin (IVER), doramectin (DORA), and moxidectin (MOXI) subcutaneous (SC) formulations in treated calves. The study was conducted using indigenous (Bos indicus) calves treated with SC formulation at a dosage of 0.5, 0.2 or 0.05 mg/kg body weight (BW) IVER or DORA and 0.2 or 0.05 mg/kg BW MOXI. Direct skin feeding of mosquitoes and animal blood sampling were performed at 4, 8, 12, and 24 h and on days 2, 3, 5, 7, 10, 14, 21, 28, and 35 post treatment. The survival of fully fed A. arabiensis mosquitoes was monitored for 10 days. Plasma samples were analyzed using UHPLC-MS/MS. A. arabiensis mortality percentages in the 0.5 mg/kg BW DORA and IVER groups were 65.74% (95% CI: [54.98; 76.50]) and 64.53% (95% CI: [53.77; 75.29]), respectively, over 35 days post treatment. At the recommended dose (0.2 mg/kg BW), promising overall A. arabiensis mortality rates of 61.79% (95% CI: [51.55; 72.03]) and 61.78% (95% CI: [51.02; 72.54]) were observed for IVER and DORA, respectively. In contrast, A. arabiensis mortality in the MOXI group was 50.23% (95% CI: [39.87, 60.58]). At 0.2 mg/kg BW dose, area under the plasma concentration versus time curve (AUC0-inf) values for IVER, DORA, and MOXI were 382.53 ± 133.25, 395.41 ± 132.12, and 215.85 ± 63.09 ng day/mL, respectively. An extended elimination half-life (T1/2el) was recorded for DORA (4.28 ± 0.93 d), at 0.2 mg/kg BW dose level, compared to that for IVER (3.16 ± 1.47 d). The T1/2el of MOXI was 2.17 ± 0.44 day. A maximum plasma concentration (Cmax) was recorded earlier for MOXI (10 h) than for IVER (1.6 days) and longer for DORA (3.0 days). For DORA and IVER, significant differences were found in T1/2el (P<0.05), Cmax (P<0.01), and AUC0-inf (P<0.01) between the higher 0.5 mg/kg BW and the lower 0.05 mg/kg BW doses. The T1/2el and AUC0-inf of DORA and IVER in the present study were significantly (p < 0.05) correlated with the observed insecticidal efficacy against A. arabiensis mosquitoes at 0.2 mg/kg a dose. Therefore, treating cattle with IVER or DORA could complement the malaria vector control interventions, especially in Ethiopia, where the zoophilic malaria vector A. arabiensis majorly contribute for residual malaria transmission.
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Affiliation(s)
- Gemechu Zeleke
- Department of Pathobiology, Pharmacology and Zoological Medicine, Faculty of Veterinary Medicine, Salisburylaan 133, Merelbeke, Belgium; School of Pharmacy, Institute of Health, Jimma University, Jimma, Ethiopia
| | - Luc Duchateau
- Biometrics Research Center, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, Merelbeke, Belgium
| | - Delenasaw Yewhalaw
- School of Medical Laboratory Sciences, Institute of Health, Jimma University, Jimma, Ethiopia
| | - Sultan Suleman
- School of Pharmacy, Institute of Health, Jimma University, Jimma, Ethiopia
| | - Mathias Devreese
- Department of Pathobiology, Pharmacology and Zoological Medicine, Faculty of Veterinary Medicine, Salisburylaan 133, Merelbeke, Belgium.
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Ominde KM, Kamau Y, Karisa J, Muturi MN, Kiuru C, Wanjiku C, Babu L, Yaah F, Tuwei M, Musani H, Ondieki Z, Muriu S, Mwangangi J, Chaccour C, Maia MF. A field bioassay for assessing ivermectin bio-efficacy in wild malaria vectors. Malar J 2023; 22:291. [PMID: 37777725 PMCID: PMC10542238 DOI: 10.1186/s12936-023-04718-9] [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: 03/06/2023] [Accepted: 09/13/2023] [Indexed: 10/02/2023] Open
Abstract
BACKGROUND Ivermectin (IVM) mass drug administration is a candidate complementary malaria vector control tool. Ingestion of blood from IVM treated hosts results in reduced survival in mosquitoes. Estimating bio-efficacy of IVM on wild-caught mosquitoes requires they ingest the drug in a blood meal either through a membrane or direct feeding on a treated host. The latter, has ethical implications, and the former results in low feeding rates. Therefore, there is a need to develop a safe and effective method for IVM bio-efficacy monitoring in wild mosquitoes. METHODS Insectary-reared Anopheles gambiae s.s. were exposed to four IVM doses: 85, 64, 43, 21 ng/ml, and control group (0 ng/ml) in three different solutions: (i) blood, (ii) 10% glucose, (iii) four ratios (1:1, 1:2, 1:4, 1:8) of blood in 10% glucose, and fed through filter paper. Wild-caught An. gambiae s.l. were exposed to 85, 43 and 21 ng/ml IVM in blood and 1:4 ratio of blood-10% glucose mixture. Survival was monitored for 28 days and a pool of mosquitoes from each cohort sacrificed immediately after feeding and weighed to determine mean weight of each meal type. RESULTS When administered in glucose solution, mosquitocidal effect of IVM was not comparable to the observed effects when similar concentrations were administered in blood. Equal concentrations of IVM administered in blood resulted in pronounced reductions in mosquito survival compared to glucose solution only. However, by adding small amounts of blood to glucose solution, mosquito mortality rates increased resulting in similar effects to what was observed during blood feeding. CONCLUSION Bio-efficacy of ivermectin is strongly dependent on mode of drug delivery to the mosquito and likely influenced by digestive processes. The assay developed in this study is a good candidate for field-based bio-efficacy monitoring: wild mosquitoes readily feed on the solution, the assay can be standardized using pre-selected concentrations and by not involving treated blood hosts (human or animal) variation in individual pharmacokinetic profiles as well as ethical issues are bypassed. Meal volumes did not explain the difference in the lethality of IVM across the different meal types necessitating further research on the underlying mechanisms.
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Affiliation(s)
- Kelly M Ominde
- Department of Biosciences, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.
- Department of Biological Sciences, and Pwani University Biosciences Research Centre, Pwani University, Kilifi, Kenya.
| | - Yvonne Kamau
- Department of Biosciences, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Jonathan Karisa
- Department of Biosciences, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
- Department of Biological Sciences, and Pwani University Biosciences Research Centre, Pwani University, Kilifi, Kenya
| | - Martha N Muturi
- Department of Biosciences, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | | | - Caroline Wanjiku
- Department of Biosciences, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Lawrence Babu
- Department of Biosciences, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Festus Yaah
- Department of Biosciences, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Mercy Tuwei
- Department of Biosciences, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
- Department of Biological Sciences, and Pwani University Biosciences Research Centre, Pwani University, Kilifi, Kenya
| | - Haron Musani
- Department of Biosciences, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Zedekiah Ondieki
- Department of Biosciences, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Simon Muriu
- Department of Biosciences, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
- Department of Biological Sciences, and Pwani University Biosciences Research Centre, Pwani University, Kilifi, Kenya
| | - Joseph Mwangangi
- Department of Biosciences, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Carlos Chaccour
- ISGlobal, Barcelona, Spain
- Ciberinfec, Madrid, Spain
- Faculty of Medicine, Universidad de Navarra, Pamplona, Spain
| | - Marta F Maia
- Department of Biosciences, KEMRI-Wellcome Trust Research Programme, Kilifi, Kenya.
- Centre for Global Health and Tropical Medicine and Nuffield Department of Medicine, University of Oxford, Oxford, UK.
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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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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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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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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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9
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Shakya M, Nandi A, Fular A, Kumar S, Bisht N, Sharma AK, Singh K, Kumar R, Kumar S, Juliet S, Ghosh S. Synergistic property of piperonyl butoxide, diethyl maleate, triphenyl phosphate and verapamil hydrochloride with deltamethrin and ivermectin against Rhipicephalus microplus ticks. Ticks Tick Borne Dis 2022; 13:102006. [PMID: 35917692 DOI: 10.1016/j.ttbdis.2022.102006] [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: 11/11/2021] [Revised: 06/16/2022] [Accepted: 07/16/2022] [Indexed: 11/24/2022]
Abstract
The present study was taken up to evaluate the synergistic properties of piperonyl butoxide (PBO), diethyl maleate (DEM), triphenyl phosphate (TPP) and verapamil (VER) with deltamethrin (DLM) and ivermectin (IVM) against DLM and IVM resistant tick populations collected from Madhya Pradesh and Punjab states of India. The collected field tick populations were resistant to DLM (Resistance Factor [RF] in the range of 21.71-32.98) and IVM (RF in the range of 1.89-4.98). A strong synergism between DLM and, IVM with PBO and IVM with VER was noticed. The synergistic efficacy of PBO and VER with IVM in reducing the lethal concentration 50 (LC50) value (1.69-5.72 times for PBO and 3.00-10.62 times for VER) of IVM in resistant ticks suggest that a combination of these synergists with IVM can significantly enhance the effectiveness of IVM against IVM-resistant Rhipicephlaus microplus populations gradually establishing in the different parts of the country. The synergistic efficiency of PBO with DLM in reducing the LC50 value was 2.65 and 18.01 times, respectively, against DLM- resistant two R. microplus populations (KTN and LDH). The study revealed the gradual establishment of DLM and IVM resistant populations in the surveyed states suggesting the need to adopt required resistance management strategies. The use of synergists with DLM and IVM has emerged as an effective approach for controlling the acaricide-resistant ticks.
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Affiliation(s)
- Mukesh Shakya
- Entomology Laboratory, Division of Parasitology, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh 243112, India
| | - Abhijit Nandi
- Entomology Laboratory, Division of Parasitology, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh 243112, India
| | - Ashutosh Fular
- Entomology Laboratory, Division of Parasitology, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh 243112, India
| | - Sachin Kumar
- Entomology Laboratory, Division of Parasitology, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh 243112, India
| | - Nisha Bisht
- Entomology Laboratory, Division of Parasitology, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh 243112, India
| | - Anil Kumar Sharma
- Entomology Laboratory, Division of Parasitology, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh 243112, India
| | - Kaushlendra Singh
- Entomology Laboratory, Division of Parasitology, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh 243112, India
| | - Rajesh Kumar
- Division of Agricultural Chemicals, ICAR-Indian Agricultural Research Institute, New Delhi 110 012, India
| | - Satyanshu Kumar
- ICAR-Directorate of Medicinal and Aromatic Plants Research, Boriavi, Anand, Gujarat 387310, India
| | - Sanis Juliet
- Department of Veterinary Pharmacology and Toxicology, College of Veterinary and Animal Sciences, Pookode, Wayanad, Kerala 673 576, India
| | - Srikanta Ghosh
- Entomology Laboratory, Division of Parasitology, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh 243112, India.
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Holcomb KM, Nguyen C, Foy BD, Ahn M, Cramer K, Lonstrup ET, Mete A, Tell LA, Barker CM. Effects of ivermectin treatment of backyard chickens on mosquito dynamics and West Nile virus transmission. PLoS Negl Trop Dis 2022; 16:e0010260. [PMID: 35333866 PMCID: PMC9012369 DOI: 10.1371/journal.pntd.0010260] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 04/15/2022] [Accepted: 02/14/2022] [Indexed: 11/18/2022] Open
Abstract
Background Vector control strategies typically rely on pesticides to target mosquitoes involved in enzootic and zoonotic transmission of West Nile virus (WNV). Nevertheless, increasing insecticide resistance and a desire to reduce pesticide usage provide the impetus for developing alternative strategies. Ivermectin (IVM), an antiparasitic drug which is widely used in human and veterinary medicine, is a potential alternative for targeted control because Culex mosquitoes experience increased mortality following ingestion of IVM in bloodmeals. Methodology/Principal findings We conducted a randomized field trial to investigate the impact of treating backyard chicken flocks with IVM in urban neighborhoods across Davis, California on mosquito populations and WNV transmission dynamics. We observed a significant reduction in WNV seroconversions in treated vs. untreated chickens, suggesting a reduction in WNV transmission intensity around treated flocks. We also detected a reduction in parity rates of Cx. tarsalis near treated vs. untreated flocks and increased mortality in wild mosquitoes following a bloodmeal on treated chickens (IVM serum concentration > 5ng/mL) vs. chickens with IVM serum concentrations < 5 ng/mL. However, we did not find a significant difference in abundance or infection prevalence in mosquitoes between treatment groups associated with the reductions in seroconversions. Mosquito immigration from surrounding larval habitat, relatively low WNV activity in the study area, and variable IVM serum concentrations likely contributed to uncertainty about the impact. Conclusions/Significance Taken together, our results point to a reduction in WNV transmission due to the impact of IVM on Culex mosquito populations and support the ongoing investigation of oral administration of IVM to wild birds for local control of WNV transmission, although further work is needed to optimize dosing and understand effects on entomological endpoints. Current mosquito control strategies aimed to prevent pathogen transmission to humans have limited ability to target mosquitoes involved in amplification and spillover transmission of pathogens like West Nile virus (WNV). Additionally, growing prevalence of insecticide resistance in mosquito populations limit the efficacy of these insecticide-based control strategies. Ivermectin (IVM) provides an alternative avenue for control by increasing the mortality of mosquitoes that ingest this drug in bloodmeals. Therefore, IVM treatment of avian species that account for the majority of mosquito bloodmeals during the WNV transmission season could be an effective control strategy. Building on pilot studies indicating the efficacy and feasibility of IVM-deployment for WNV control, we performed a randomized field trial to investigate the impact of IVM-treatment of backyard chickens on local population dynamics of Culex mosquitoes and WNV transmission. We were able to link changes in mosquito populations to reduction in WNV transmission, as measured by chicken seroconversions, through IVM-induced mortality in mosquitoes. However, further work is needed to identify the impact of treatment on mosquito abundance and infection prevalence to fully attribute observed changes to IVM administration. Overall, our results support IVM treatment as a potentially effective alternative to insecticide-based vector control strategies and one that can be used to target WNV transmission on the local scale.
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Affiliation(s)
- Karen M. Holcomb
- Davis Arbovirus Research and Training Laboratory, Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - Chilinh Nguyen
- Center for Vector-borne Infectious Diseases, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Brian D. Foy
- Center for Vector-borne Infectious Diseases, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Michelle Ahn
- Davis Arbovirus Research and Training Laboratory, Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - Kurt Cramer
- Davis Arbovirus Research and Training Laboratory, Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - Emma T. Lonstrup
- Davis Arbovirus Research and Training Laboratory, Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - Asli Mete
- California Animal Health and Food Safety Lab, Department of Pathology, Microbiology & Immunology, University of California, Davis, California, United States of America
| | - Lisa A. Tell
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - Christopher M. Barker
- Davis Arbovirus Research and Training Laboratory, Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, California, United States of America
- * E-mail:
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