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Shah HK, Srinivasan V, Venkatesan S, Balakrishnan V, Candasamy S, Mathew N, Kumar A, Kuttiatt VS. Evaluation of the mosquitocidal efficacy of fluralaner, a potential candidate for drug based vector control. Sci Rep 2024; 14:5628. [PMID: 38454095 PMCID: PMC10920869 DOI: 10.1038/s41598-024-56053-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: 11/27/2023] [Accepted: 03/01/2024] [Indexed: 03/09/2024] Open
Abstract
Vector control is a key intervention against mosquito borne diseases. However, conventional methods have several limitations and alternate strategies are in urgent need. Vector control with endectocides such as ivermectin is emerging as a novel strategy. The short half-life of ivermectin is a limiting factor for its application as a mass therapy tool for vector control. Isoxazoline compounds like fluralaner, a class of veterinary acaricides with long half-life hold promise as an alternative. However, information about their mosquitocidal effect is limited. We explored the efficacy of fluralaner against laboratory reared vector mosquitoes-Aedes aegypti, Anopheles stephensi, and, Culex quinquefasciatus. 24 h post-blood feeding, fluralaner showed a significant mosquitocidal effect with LC50 values in the range of 24.04-49.82 ng/mL for the three different mosquito species tested. Effects on life history characteristics (fecundity, egg hatch success, etc.) were also observed and significant effects were noted at drug concentrations of 20, 25 and 45 ng/mL for Ae. aegypti, An. stephensi, and, Cx. quinquefasciatus respectively. At higher drug concentration of 250 ng/mL, significant mortality was observed within 1-2 h of post blood feeding. Potent mosquitocidal effect coupled with its long half-life makes fluralaner an excellent candidate for drug based vector control strategies.
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Affiliation(s)
| | | | | | | | | | - Nisha Mathew
- ICMR-Vector Control Research Centre, Puducherry, 605 006, India
| | - Ashwani Kumar
- ICMR-Vector Control Research Centre, Puducherry, 605 006, India
- Saveetha Institute of Medical and Technical Sciences, Saveetha University, Thandalam, Kanchipuram, 602 105, India
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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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Zeleke G, De Baere S, Suleman S, Devreese M. Development and Validation of a Reliable UHPLC-MS/MS Method for Simultaneous Quantification of Macrocyclic Lactones in Bovine Plasma. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27030998. [PMID: 35164263 PMCID: PMC8838099 DOI: 10.3390/molecules27030998] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 01/28/2022] [Accepted: 01/28/2022] [Indexed: 11/16/2022]
Abstract
A fast, accurate and reliable ultra-high performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS) method was developed for simultaneous quantification of ivermectin (IVER), doramectin (DORA), and moxidectin (MOXI) in bovine plasma. A priority for sample preparation was the eradication of possible infectious diseases to avoid travel restrictions. The sample preparation was based on protein precipitation using 1% formic acid in acetonitrile, followed by Ostro® 96-well plate pass-through sample clean-up. The simple and straightforward procedure, along with the short analysis time, makes the current method unique and suitable for a large set of sample analyses per day for PK studies. Chromatographic separation was performed using an Acquity UPLC HSS-T3 column, with 0.01% acetic acid in water and methanol, on an Acquity H-Class ultra-high performance liquid chromatograph (UHPLC) system. The MS/MS instrument was a Xevo TQ-S® mass spectrometer, operating in the positive electrospray ionization mode and two multiple reaction monitoring (MRM) transitions were monitored per component. The MRM transitions of m/z 897.50 > 753.4 for IVER, m/z 921.70 > 777.40 for DORA and m/z 640.40 > 123.10 for MOXI were used for quantification. The method validation was performed using matrix-matched calibration curves in a concentration range of 1 to 500 ng/mL. Calibration curves fitted a quadratic regression model with 1/x2 weighting (r ≥ 0.998 and GoF ≤ 4.85%). Limits of quantification (LOQ) values of 1 ng/mL were obtained for all the analytes, while the limits of detection (LOD) were 0.02 ng/mL for IVER, 0.03 ng/mL for DORA, and 0.58 ng/mL for MOXI. The results of within-day (RSD < 6.50%) and between-day (RSD < 8.10%) precision and accuracies fell within acceptance ranges. No carry-over and no peak were detected in the UHPLC-MS/MS chromatogram of blank samples showing good specificity of the method. The applicability of the developed method was proved by an analysis of the field PK samples.
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Affiliation(s)
- Gemechu Zeleke
- Laboratory of Pharmacology and Toxicology, Department of Pathobiology, Pharmacology and Zoological Medicine, Faculty of Veterinary Medicine, Ghent University, B-9820 Merelbeke, Belgium; (G.Z.); (S.D.B.)
- Institute of Health, School of Pharmacy, Jimma University, Jimma P.O. Box 378, Ethiopia;
| | - Siegrid De Baere
- Laboratory of Pharmacology and Toxicology, Department of Pathobiology, Pharmacology and Zoological Medicine, Faculty of Veterinary Medicine, Ghent University, B-9820 Merelbeke, Belgium; (G.Z.); (S.D.B.)
| | - Sultan Suleman
- Institute of Health, School of Pharmacy, Jimma University, Jimma P.O. Box 378, Ethiopia;
| | - Mathias Devreese
- Laboratory of Pharmacology and Toxicology, Department of Pathobiology, Pharmacology and Zoological Medicine, Faculty of Veterinary Medicine, Ghent University, B-9820 Merelbeke, Belgium; (G.Z.); (S.D.B.)
- Correspondence: ; Tel.: +32-(0)9-264-73-47
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Ahmad SS, Rahi M, Saroha P, Sharma A. Ivermectin as an endectocide may boost control of malaria vectors in India and contribute to elimination. Parasit Vectors 2022; 15:20. [PMID: 35012612 PMCID: PMC8744265 DOI: 10.1186/s13071-021-05124-3] [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: 08/13/2021] [Accepted: 12/12/2021] [Indexed: 11/10/2022] Open
Abstract
Malaria constitutes one of the largest public health burdens faced by humanity. Malaria control has to be an efficient balance between diagnosis, treatment and vector control strategies. The World Health Organization currently recommends indoor residual spraying and impregnated bed nets as two malaria vector control methods that have shown robust and persistent results against endophilic and anthropophilic mosquito species. The Indian government launched the National Framework for Malaria Elimination in 2016 with the aim to achieve the elimination of malaria in a phased and strategic manner and to sustain a nation-wide malaria-free status by 2030. India is currently in a crucial phase of malaria elimination and novel vector control strategies maybe helpful in dealing with various challenges, such as vector behavioural adaptations and increasing insecticide resistance among the Anopheles populations of India. Ivermectin can be one such new tool as it is the first endectocide to be approved in both animals and humans. Trials of ivermectin have been conducted in endemic areas of Africa with promising results. In this review, we assess available data on ivermectin as an endectocide and propose that this endectocide should be explored as a vector control tool for malaria in India.
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Affiliation(s)
- Sundus Shafat Ahmad
- Indian Council of Medical Research (ICMR)-National Institute of Malaria Research, New Delhi, India
| | - Manju Rahi
- Indian Council of Medical Research, New Delhi, India.,Academy of Scientific and Innovative Research (AcSir), Ghaziabad, India
| | - Poonam Saroha
- Indian Council of Medical Research (ICMR)-National Institute of Malaria Research, New Delhi, India.,Academy of Scientific and Innovative Research (AcSir), Ghaziabad, India
| | - Amit Sharma
- Indian Council of Medical Research (ICMR)-National Institute of Malaria Research, New Delhi, India. .,International Centre for Genetic Engineering and Biotechnology, New Delhi, India. .,Academy of Scientific and Innovative Research (AcSir), Ghaziabad, India.
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Ruiz-Castillo P, Rist C, Rabinovich R, Chaccour C. Insecticide-treated livestock: a potential One Health approach to malaria control in Africa. Trends Parasitol 2021; 38:112-123. [PMID: 34756820 DOI: 10.1016/j.pt.2021.09.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 09/16/2021] [Accepted: 09/16/2021] [Indexed: 12/20/2022]
Abstract
New vector-control tools are urgently needed to reduce malaria in areas where there is significant transmission after deployment of indoor residual spraying (IRS) and insecticide treated nets. Insecticide-treated livestock (ITL) is a potential novel strategy by which zoophagic mosquitos are killed after feeding upon animals treated with an insecticide. Although there are several insecticide candidates in the pipeline with a wide efficacy range against mosquitos, additional field studies with epidemiological outcomes are required to test the impact of this intervention on malaria transmission. Insecticides under consideration have long been used in livestock to improve animal health and productivity, but each has food and environmental safety considerations. Therefore, moving ITL from a concept to implementation will require a One Health framework.
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Affiliation(s)
| | - Cassidy Rist
- Virginia Maryland College of Veterinary Medicine at Virginia Tech, Blacksburg, VA, USA
| | - Regina Rabinovich
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain; Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Carlos Chaccour
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain; Facultad de Medicina, Universidad de Navarra, Pamplona, Spain
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Khaligh FG, Jafari A, Silivanova E, Levchenko M, Rahimi B, Gholizadeh S. Endectocides as a complementary intervention in the malaria control program: a systematic review. Syst Rev 2021; 10:30. [PMID: 33455581 PMCID: PMC7812718 DOI: 10.1186/s13643-021-01578-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Accepted: 01/02/2021] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Malaria is the most common vector-borne disease transmitted to humans by Anopheles mosquitoes. Endectocides and especially ivermectin will be available as a vector control tool soon. The current review could be valuable for trial design and clinical studies to control malaria transmission. METHODS PubMed/MEDLINE, Scopus, Web of Science, and Science Direct were searched for original English published papers on ("Malaria chemical control" OR "Malaria elimination" OR "Anopheles vector control" OR "Malaria zooprophylaxis") AND ("Systemic insecticides" OR "Endectocides" OR "Ivermectin"). The last search was from 19 June 2019 to 31 December 2019. It was updated on 17 November 2020. Two reviewers (SG and FGK) independently reviewed abstracts and full-text articles. Data were extracted by one person and checked by another. As meta-analyses were not possible, a qualitative summary of results was performed. RESULTS Thirty-six published papers have used systemic insecticides/endectocides for mosquito control. Most of the studies (56.75%) were done on Anopheles gambiae complex species on doses from 150 μg/kg to 400 μg/kg in several studies. Target hosts for employing systemic insecticides/drugs were animals (44.2%, including rabbit, cattle, pig, and livestock) and humans (32.35%). CONCLUSIONS Laboratory and field studies have highlighted the potential of endectocides in malaria control. Ivermectin and other endectocides could soon serve as novel malaria transmission control tools by reducing the longevity of Anopheles mosquitoes that feed on treated hosts, potentially decreasing Plasmodium parasite transmission when used as mass drug administration (MDA).
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Affiliation(s)
- Fereshteh Ghahvechi Khaligh
- Social Determinants of Health Research Center, Clinical Research Institute, Urmia University of Medical Sciences, Urmia, Iran.,Medical Entomology Department, School of Public Health, Urmia University of Medical Sciences, Urmia, Iran
| | - Abbas Jafari
- Department of Clinical Toxicology, School of Medicine, Urmia University of Medical Sciences, Urmia, Iran.,Cellular and Molecular Research Center, Research Institute on Cellular and Molecular Medicine, Urmia University of Medical Sciences, Urmia, Iran
| | - Elena Silivanova
- All-Russian Scientific Research Institute of Veterinary Entomology and Arachnology, Branch of Federal State Institution Federal Research Centre Tyumen Scientific Centre, Siberian Branch of the Russian Academy of Sciences (ASRIVEA - Branch of Tyumen Scientific Centre SB RAS), Institutskaya st. 2, Tyumen, Russian Federation, 625041
| | - Mikhail Levchenko
- All-Russian Scientific Research Institute of Veterinary Entomology and Arachnology, Branch of Federal State Institution Federal Research Centre Tyumen Scientific Centre, Siberian Branch of the Russian Academy of Sciences (ASRIVEA - Branch of Tyumen Scientific Centre SB RAS), Institutskaya st. 2, Tyumen, Russian Federation, 625041
| | - Bahlol Rahimi
- Department of Health Information Technology, School of Applied Medical Sciences, Urmia University of Medical Sciences, Urmia, Iran
| | - Saber Gholizadeh
- Social Determinants of Health Research Center, Clinical Research Institute, Urmia University of Medical Sciences, Urmia, Iran. .,Medical Entomology Department, School of Public Health, Urmia University of Medical Sciences, Urmia, Iran.
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Chaccour C. Veterinary endectocides for malaria control and elimination: prospects and challenges. Philos Trans R Soc Lond B Biol Sci 2020; 376:20190810. [PMID: 33357062 DOI: 10.1098/rstb.2019.0810] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Residual transmission is the persistence of malaria transmission after scale-up of appropriate vector control tools and is one of the key challenges for malaria elimination today. Although long associated with outdoor biting, other mosquito behaviours such as partly feeding upon animals contribute greatly to sustaining transmission. Peri-domestic livestock can be used as decoy to protect humans from blood-seeking vectors but this approach often leads to an increased malaria risk in a phenomenon known as zoopotentiation. Treating the said livestock with drugs capable of killing intestinal parasites as well as mosquitoes that feed upon them has the potential to tackle malaria through a previously unexplored mechanism. The advantages and challenges associated with this approach are briefly discussed here. Numerous references are purposely provided. This article is part of the theme issue 'Novel control strategies for mosquito-borne diseases'.
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Affiliation(s)
- Carlos Chaccour
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Rosello 132, 5ª 2ª, 08036 Barcelona, Spain.,Ifakara Health Institute, Off Mlabani Passage, PO Box 53, Ifakara, United Republic of Tanzania.,Faculty of Medicine, Universidad de Navarra, Calle de Irunlarrea 1, 31008 Pamplona, Spain
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Mlacha YP, Chaki PP, Muhili A, Massue DJ, Tanner M, Majambere S, Killen GF, Govella NJ. Reduced human-biting preferences of the African malaria vectors Anopheles arabiensis and Anopheles gambiae in an urban context: controlled, competitive host-preference experiments in Tanzania. Malar J 2020; 19:418. [PMID: 33218346 PMCID: PMC7678205 DOI: 10.1186/s12936-020-03495-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 11/11/2020] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Host preference is a critical determinant of human exposure to vector-borne infections and the impact of vector control interventions. Widespread use of long-lasting insecticide-treated nets (LLINs) and indoor residual spraying (IRS) across sub-Saharan Africa, which protect humans against mosquitoes, may select for altered host preference traits of malaria vectors over the long term. Here, the host preferences of Anopheles arabiensis and Anopheles gambiae sensu stricto (s.s.) were experimentally assessed in the field, using direct host-preference assays in two distinct ecological settings in Tanzania. METHODS Eight Ifakara Tent Trap (ITT), four baited with humans and four with bovine calves, were simultaneously used to catch malaria vectors in open field sites in urban and rural Tanzania. The numbers of mosquitoes collected in human-baited traps versus calf-baited traps were used to estimate human feeding preference for each site's vector species. RESULTS The estimated proportion [95% confidence interval (CI)] of mosquitoes attacking humans rather than cattle was 0.60 [0.40, 0.77] for An. arabiensis in the rural setting and 0.61 [0.32, 0.85] for An. gambiae s.s. in the urban setting, indicating no preference for either host in both cases (P = 0.32 and 0.46, respectively) and no difference in preference between the two (Odds Ratio (OR) [95%] = 0.95 [0.30, 3.01], P = 0.924). However, only a quarter of An. arabiensis in the urban setting attacked humans (0.25 [0.09, 0.53]), indicating a preference for cattle that approached significance (P = 0.08). Indeed, urban An. arabiensis were less likely to attack humans rather than cattle when compared to the same species in the rural setting (OR [95%] = 0.21 [0.05, 0.91], P = 0.037). CONCLUSION Urban An. arabiensis had a stronger preference for cattle than the rural population and urban An. gambiae s.s. showed no clear preference for either humans or cattle. In the urban setting, both species exhibited stronger tendencies to attack cattle than previous studies of the same species in rural contexts. Cattle keeping may, therefore, particularly limit the impact of human-targeted vector control interventions in Dar es Salaam and perhaps in other African towns and cities.
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Affiliation(s)
- Yeromin P Mlacha
- Ecological Sciences Department, Ifakara Health Institute, Environmental Health, Kiko Avenue, P.O. Box 78373, Mikocheni, Dar es Salaam, United Republic of Tanzania.
- Swiss Tropical and Public Health Institute, Basel, Switzerland.
- University of Basel, Basel, Switzerland.
| | - Prosper P Chaki
- Ecological Sciences Department, Ifakara Health Institute, Environmental Health, Kiko Avenue, P.O. Box 78373, Mikocheni, Dar es Salaam, United Republic of Tanzania
- The Pan-African Mosquito Control Association (PAMCA), KEMRI Headquarters, Mbagathi Road, Nairobi, 54840-00200, Nairobi, Kenya
| | - Athuman Muhili
- Ecological Sciences Department, Ifakara Health Institute, Environmental Health, Kiko Avenue, P.O. Box 78373, Mikocheni, Dar es Salaam, United Republic of Tanzania
| | - Dennis J Massue
- Univerity of Dar Es Salaam, Mbeya College of Health and Allied Sciences, P.O. Box 608, Mbeya, United Republic of Tanzania
- Amani Research Centre, National Institute for Medical Research, P.O. Box 81, Muheza-Tanga, United Republic of Tanzania
| | - Marcel Tanner
- Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Silas Majambere
- The Pan-African Mosquito Control Association (PAMCA), KEMRI Headquarters, Mbagathi Road, Nairobi, 54840-00200, Nairobi, Kenya
| | - Gerry F Killen
- Ecological Sciences Department, Ifakara Health Institute, Environmental Health, Kiko Avenue, P.O. Box 78373, Mikocheni, Dar es Salaam, United Republic of Tanzania
- Liverpool School of Tropical Medicine, Vector Biology Department, Pembroke Place, Liverpool, L3 5QA, UK
- School of Biological, Earth & Environmental Sciences and Environmental Research Institute, University College Cork, Cork, Republic of Ireland
| | - Nicodem J Govella
- Ecological Sciences Department, Ifakara Health Institute, Environmental Health, Kiko Avenue, P.O. Box 78373, Mikocheni, Dar es Salaam, United Republic of Tanzania
- The Nelson Mandela, African Institution of Science and Technology, The School of Life Science and Bio-Engineering (LISBE), P.O.BOX 447, Tengeru, Arusha, United Republic of Tanzania
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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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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: 46] [Impact Index Per Article: 11.5] [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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Orsborne J, Mohammed AR, Jeffries CL, Kristan M, Afrane YA, Walker T, Yakob L. Evidence of extrinsic factors dominating intrinsic blood host preferences of major African malaria vectors. Sci Rep 2020; 10:741. [PMID: 31959845 PMCID: PMC6971008 DOI: 10.1038/s41598-020-57732-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 12/02/2019] [Indexed: 11/20/2022] Open
Abstract
One of the key determinants of a haematophagous vector’s capacity to transmit pathogens is its selection of which host to secure a blood meal from. This choice is influenced by both intrinsic (genetic) and extrinsic (environmental) factors, but little is known of their relative contributions. Blood fed Anopheles mosquitoes were collected from a malaria endemic village in Ghana. Collections were conducted across a range of different host availabilities and from both indoor and outdoor locations. These environmental factors were shown to impact dramatically the host choice of caught malaria vectors: mosquitoes caught indoors were ten-fold more likely to have sourced their blood meal from humans; and a halving in odds of being human-fed was found for mosquitoes caught only 25 m from the centre of the village. For the first time, we demonstrate that anthropophagy was better explained by extrinsic factors (namely, local host availability and indoor/outdoor trapping location) than intrinsic factors (namely, the (sibling) species of the mosquito caught) (respective Akaike information criterion estimates: 243.0 versus 359.8). Instead of characterizing biting behaviour on a taxonomic level, we illustrate the importance of assessing local entomology. Accounting for this behavioural plasticity is important, both in terms of measuring effectiveness of control programmes and in informing optimal disease control strategies.
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Affiliation(s)
- James Orsborne
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, UK
| | - Abdul Rahim Mohammed
- Department of Medical Microbiology, College of Health Sciences, University of Ghana, Korle Bu, Accra, Ghana
| | - Claire L Jeffries
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, UK
| | - Mojca Kristan
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, UK
| | - Yaw A Afrane
- Department of Medical Microbiology, College of Health Sciences, University of Ghana, Korle Bu, Accra, Ghana
| | - Thomas Walker
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, UK
| | - Laith Yakob
- Department of Disease Control, London School of Hygiene & Tropical Medicine, London, UK.
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