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Swai JK, Soto AC, Ntabaliba WS, Kibondo UA, Ngonyani HA, Mseka AP, Ortiz A, Chura MR, Mascari TM, Moore SJ. Efficacy of the spatial repellent product Mosquito Shield™ against wild pyrethroid-resistant Anopheles arabiensis in south-eastern Tanzania. Malar J 2023; 22:249. [PMID: 37649032 PMCID: PMC10466708 DOI: 10.1186/s12936-023-04674-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 08/13/2023] [Indexed: 09/01/2023] Open
Abstract
BACKGROUND Spatial repellents that create airborne concentrations of an active ingredient (AI) within a space offer a scalable solution to further reduce transmission of malaria, by disrupting mosquito behaviours in ways that ultimately lead to reduced human-vector contact. Passive emanator spatial repellents can protect multiple people within the treated space and can last for multiple weeks without the need for daily user touchpoints, making them less intrusive interventions. They may be particularly advantageous in certain use cases where implementation of core tools may be constrained, such as in humanitarian emergencies and among mobile at-risk populations. The purpose of this study was to assess the efficacy of Mosquito Shield™ deployed in experimental huts against wild, free-flying, pyrethroid-resistant Anopheles arabiensis mosquitoes in Tanzania over 1 month. METHODS The efficacy of Mosquito Shield™ transfluthrin spatial repellent in reducing mosquito lands and blood-feeding was evaluated using 24 huts: sixteen huts were allocated to Human Landing Catch (HLC) collections and eight huts to estimating blood-feeding. In both experiments, half of the huts received no intervention (control) while the remaining received the intervention randomly allocated to huts and remained fixed for the study duration. Outcomes measured were mosquito landings, blood-fed, resting and dead mosquitoes. Data were analysed by multilevel mixed effects regression with appropriate dispersion and link function accounting for volunteer, hut and day. RESULTS Landing inhibition was estimated to be 70% (57-78%) [IRR 0.30 (95% CI 0.22-0.43); p < 0.0001] and blood-feeding inhibition was estimated to be 69% (56-79%) [IRR 0.31 (95% CI 0.21-0.44; p < 0.0001] There was no difference in the protective efficacy estimates of landing and blood-feeding inhibition [IRR 0.98 (95% CI 0.53-1.82; p = 0.958]. CONCLUSIONS This study demonstrated that Mosquito Shield™ was efficacious against a wild pyrethroid-resistant strain of An. arabiensis mosquitoes in Tanzania for up to 1 month and could be used as a complementary or stand-alone tool where gaps in protection offered by core malaria vector control tools exist. HLC is a suitable technique for estimating bite reductions conferred by spatial repellents especially where direct blood-feeding measurements are not practical or are ethically limited.
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Affiliation(s)
- Johnson Kyeba Swai
- Vector Control Product Testing Unit, Environmental Health and Ecological Science Department, Ifakara Health Institute, Bagamoyo, Tanzania
- Department of Epidemiology and Public, Health Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Alina Celest Soto
- Vector Control Product Testing Unit, Environmental Health and Ecological Science Department, Ifakara Health Institute, Bagamoyo, Tanzania
- Department of Epidemiology and Public, Health Swiss Tropical and Public Health Institute, Allschwil, Switzerland
| | - Watson Samuel Ntabaliba
- Vector Control Product Testing Unit, Environmental Health and Ecological Science Department, Ifakara Health Institute, Bagamoyo, Tanzania
| | - Ummi Abdul Kibondo
- Vector Control Product Testing Unit, Environmental Health and Ecological Science Department, Ifakara Health Institute, Bagamoyo, Tanzania
| | - Hassan Ahamad Ngonyani
- Vector Control Product Testing Unit, Environmental Health and Ecological Science Department, Ifakara Health Institute, Bagamoyo, Tanzania
| | - Antony Pius Mseka
- Vector Control Product Testing Unit, Environmental Health and Ecological Science Department, Ifakara Health Institute, Bagamoyo, Tanzania
| | | | | | | | - Sarah Jane Moore
- Vector Control Product Testing Unit, Environmental Health and Ecological Science Department, Ifakara Health Institute, Bagamoyo, Tanzania
- Department of Epidemiology and Public, Health Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
- School of Life Sciences and Bio Engineering, The Nelson Mandela, African Institution of Science and Technology, Tengeru, Arusha, United Republic of Tanzania
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Zahouli JZB, Edi CAV, Yao LA, Lisro EG, Adou M, Koné I, Small G, Sternberg ED, Koudou BG. Small-scale field evaluation of PermaNet ® Dual (a long-lasting net coated with a mixture of chlorfenapyr and deltamethrin) against pyrethroid-resistant Anopheles gambiae mosquitoes from Tiassalé, Côte d'Ivoire. Malar J 2023; 22:36. [PMID: 36726160 PMCID: PMC9893697 DOI: 10.1186/s12936-023-04455-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 01/16/2023] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND Due to the rapid expansion of pyrethroid-resistance in malaria vectors in Africa, Global Plan for Insecticide Resistance Management (GPIRM) has recommended the development of long-lasting insecticidal nets (LLINs), containing insecticide mixtures of active ingredients with different modes of action to mitigate resistance and improve LLIN efficacy. This good laboratory practice (GLP) study evaluated the efficacy of the chlorfenapyr and deltamethrin-coated PermaNet® Dual, in comparison with the deltamethrin and synergist piperonyl butoxide (PBO)-treated PermaNet® 3.0 and the deltamethrin-coated PermaNet® 2.0, against wild free-flying pyrethroid-resistant Anopheles gambiae sensu lato (s.l.), in experimental huts in Tiassalé, Côte d'Ivoire (West Africa). METHODS PermaNet® Dual, PermaNet® 3.0 and PermaNet® 2.0, unwashed and washed (20 washes), were tested against free-flying pyrethroid-resistant An. gambiae s.l. in the experimental huts in Tiassalé, Côte d'Ivoire from March to August 2020. Complementary laboratory cone bioassays (daytime and 3-min exposure) and tunnel tests (nightly and 15-h exposure) were performed against pyrethroid-susceptible An. gambiae sensu stricto (s.s.) (Kisumu strain) and pyrethroid-resistant An. gambiae s.l. (Tiassalé strain). RESULTS PermaNet® Dual demonstrated significantly improved efficacy, compared to PermaNet® 3.0 and PermaNet® 2.0, against the pyrethroid-resistant An. gambiae s.l. Indeed, the experimental hut trial data showed that the mortality and blood-feeding inhibition in the wild pyrethroid-resistant An. gambiae s.l. were overall significantly higher with PermaNet® Dual compared with PermaNet® 3.0 and PermaNet® 2.0, for both unwashed and washed samples. The mortality with unwashed and washed samples were 93.6 ± 0.2% and 83.2 ± 0.9% for PermaNet® Dual, 37.5 ± 2.9% and 14.4 ± 3.9% for PermaNet® 3.0, and 7.4 ± 5.1% and 11.7 ± 3.4% for PermaNet® 2.0, respectively. Moreover, unwashed and washed samples produced the respective percentage blood-feeding inhibition of 41.4 ± 6.9% and 43.7 ± 4.8% with PermaNet® Dual, 51.0 ± 5.7% and 9.8 ± 3.6% with PermaNet® 3.0, and 12.8 ± 4.3% and - 13.0 ± 3.6% with PermaNet® 2.0. Overall, PermaNet® Dual also induced higher or similar deterrence, exophily and personal protection when compared with the standard PermaNet® 3.0 and PermaNet® 2.0 reference nets, with both unwashed and washed net samples. In contrast to cone bioassays, tunnel tests predicted the efficacy of PermaNet® Dual seen in the current experimental hut trial. CONCLUSION The deltamethrin-chlorfenapyr-coated PermaNet® Dual induced a high efficacy and performed better than the deltamethrin-PBO PermaNet® 3.0 and the deltamethrin-only PermaNet® 2.0, testing both unwashed and 20 times washed samples against the pyrethroid-susceptible and resistant strains of An. gambiae s.l. The inclusion of chlorfenapyr with deltamethrin in PermaNet® Dual net greatly improved protection and control of pyrethroid-resistant An. gambiae populations. PermaNet® Dual thus represents a promising tool, with a high potential to reduce malaria transmission and provide community protection in areas compromised by mosquito vector resistance to pyrethroids.
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Affiliation(s)
- Julien Z. B. Zahouli
- grid.462846.a0000 0001 0697 1172Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire ,grid.449926.40000 0001 0118 0881Centre d’Entomologie Médicale et Vétérinaire, Université Alassane Ouattara, Bouaké, Côte d’Ivoire ,grid.416786.a0000 0004 0587 0574Swiss Tropical and Public Health Institute, Allschwil, Switzerland
| | - Constant A. V. Edi
- grid.462846.a0000 0001 0697 1172Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
| | - Laurence A. Yao
- grid.462846.a0000 0001 0697 1172Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
| | - Emmanuelle G. Lisro
- grid.462846.a0000 0001 0697 1172Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire
| | - Marc Adou
- grid.462846.a0000 0001 0697 1172Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire ,UFR Science de la Nature, Université Nagui-Abrogoua, Abidjan, Côte d’Ivoire
| | - Inza Koné
- grid.462846.a0000 0001 0697 1172Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire ,grid.410694.e0000 0001 2176 6353Université Félix Houphouët-Boingy, Abidjan, Côte d’Ivoire
| | - Graham Small
- grid.452416.0Innovative Vector Control Consortium, Liverpool, UK
| | - Eleanore D. Sternberg
- Vestergaard Sàrl, Lausanne, Switzerland ,grid.48004.380000 0004 1936 9764Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA UK
| | - Benjamin G. Koudou
- grid.462846.a0000 0001 0697 1172Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, Abidjan, Côte d’Ivoire ,UFR Science de la Nature, Université Nagui-Abrogoua, Abidjan, Côte d’Ivoire
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Azizi S, Snetselaar J, Kaaya R, Matowo J, Onen H, Shayo M, Kisengwa E, Tilya E, Manunda B, Mawa B, Mosha F, Kirby M. Implementing OECD GLP principles for the evaluation of novel vector control tools: a case study with two novel LLINs, SafeNet ® and SafeNet NF ®. Malar J 2022; 21:183. [PMID: 35690824 PMCID: PMC9188019 DOI: 10.1186/s12936-022-04208-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 05/30/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND To sustain high universal Long-Lasting Insecticidal Nets (LLINs) coverage, affordable nets that provide equivalent or better protection than standard LLINs, are required. Test facilities evaluating new LLINs require compliance to Good Laboratory Practice (GLP) standards to ensure the quality and integrity of test data. Following GLP principles allows for the reconstruction of activities during the conduct of a study and minimizes duplication of efficacy testing. This case study evaluated the efficacy of two LLINs: SafeNet NF® and SafeNet® LLIN. METHODS The study was conducted according to GLP principles and followed World Health Organization guidelines for evaluating LLINs. The LLINs were assessed in experimental huts against wild, pyrethroid-resistant Anopheles arabiensis mosquitoes. Nets were either unwashed or washed 20 times and artificially holed to simulate a used torn net. Blood-feeding inhibition and mortality were compared with a positive control (Interceptor® LLIN) and an untreated net. RESULTS Mosquito entry in the huts was reduced compared to negative control for the unwashed SafeNet NF, washed Safenet LLIN and the positive control arms. Similar exiting rates were found for all the treatment arms. Significant blood-feeding inhibition was only found for the positive control, both when washed and unwashed. All insecticide treatments induced significantly higher mortality compared to an untreated net. Compared to the positive control, the washed and unwashed SafeNet NF® resulted in similar mortality. For the SafeNet® LLINs the unwashed net had an equivalent performance, but the mortality for the washed net was significantly lower than the positive control. Internal audits of the study confirmed that all critical phases complied with Standard Operating Procedures (SOPs) and the study plan. The external audit confirmed that the study complied with GLP standards. CONCLUSIONS SafeNet NF® and SafeNet® LLIN offered equivalent protection to the positive control (Interceptor® LLIN). However, further research is needed to investigate the durability, acceptability, and residual efficacy of these nets in the community. This study demonstrated that GLP-compliant evaluation of LLINs can be successfully conducted by African research institutions.
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Affiliation(s)
- Salum Azizi
- Department of Medical Parasitology and Entomology, Kilimanjaro Christian Medical University College (KCMUCo), Moshi, 255, Tanzania. .,Pan African Malaria Vector Research Consortium (PAMVERC), Moshi, 255, Tanzania.
| | - Janneke Snetselaar
- Pan African Malaria Vector Research Consortium (PAMVERC), Moshi, 255, Tanzania.,Innovative Vector Control Consortium (IVCC), Liverpool, L3 5QA, UK.,London School of Hygiene and Tropical Medicine (LSHTM), London, WC1E 7HT, UK
| | - Robert Kaaya
- Department of Medical Parasitology and Entomology, Kilimanjaro Christian Medical University College (KCMUCo), Moshi, 255, Tanzania.,Pan African Malaria Vector Research Consortium (PAMVERC), Moshi, 255, Tanzania
| | - Johnson Matowo
- Department of Medical Parasitology and Entomology, Kilimanjaro Christian Medical University College (KCMUCo), Moshi, 255, Tanzania.,Pan African Malaria Vector Research Consortium (PAMVERC), Moshi, 255, Tanzania
| | - Hudson Onen
- Department of Zoology, Entomology and Fisheries Sciences, College of Natural Sciences, School of Biosciences, Makerere University, P.O. Box 7062, Kampala, Uganda
| | - Magreth Shayo
- Department of Medical Parasitology and Entomology, Kilimanjaro Christian Medical University College (KCMUCo), Moshi, 255, Tanzania.,Pan African Malaria Vector Research Consortium (PAMVERC), Moshi, 255, Tanzania
| | - Ezekia Kisengwa
- Department of Medical Parasitology and Entomology, Kilimanjaro Christian Medical University College (KCMUCo), Moshi, 255, Tanzania.,Pan African Malaria Vector Research Consortium (PAMVERC), Moshi, 255, Tanzania
| | - Evod Tilya
- Department of Medical Parasitology and Entomology, Kilimanjaro Christian Medical University College (KCMUCo), Moshi, 255, Tanzania.,Pan African Malaria Vector Research Consortium (PAMVERC), Moshi, 255, Tanzania
| | - Baltazari Manunda
- Department of Medical Parasitology and Entomology, Kilimanjaro Christian Medical University College (KCMUCo), Moshi, 255, Tanzania.,Pan African Malaria Vector Research Consortium (PAMVERC), Moshi, 255, Tanzania
| | - Benson Mawa
- Department of Medical Parasitology and Entomology, Kilimanjaro Christian Medical University College (KCMUCo), Moshi, 255, Tanzania.,Pan African Malaria Vector Research Consortium (PAMVERC), Moshi, 255, Tanzania
| | - Franklin Mosha
- Department of Medical Parasitology and Entomology, Kilimanjaro Christian Medical University College (KCMUCo), Moshi, 255, Tanzania.,Pan African Malaria Vector Research Consortium (PAMVERC), Moshi, 255, Tanzania
| | - Matthew Kirby
- Pan African Malaria Vector Research Consortium (PAMVERC), Moshi, 255, Tanzania.,Innovative Vector Control Consortium (IVCC), Liverpool, L3 5QA, UK
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Sirisopa P, Sukkanon C, Bangs MJ, Nakasathien S, Hii J, Grieco JP, Achee NL, Manguin S, Chareonviriyaphap T. Scientific achievements and reflections after 20 years of vector biology and control research at the Pu Teuy mosquito field research station, Thailand. Malar J 2022; 21:44. [PMID: 35164748 PMCID: PMC8842738 DOI: 10.1186/s12936-022-04061-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Accepted: 01/23/2022] [Indexed: 01/25/2023] Open
Abstract
Additional vector control tools are needed to supplement current strategies to achieve malaria elimination and control of Aedes-borne diseases in many settings in Thailand and the Greater Mekong Sub-region. Within the next decade, the vector control community, Kasetsart University (KU), and the Ministry of Higher Education, Science, Research and Innovation must take full advantage of these tools that combine different active ingredients with different modes of action. Pu Teuy Mosquito Field Research Station (MFRS), Department of Entomology, Faculty of Agriculture, Kasetsart University (KU), Thailand was established in 2001 and has grown into a leading facility for performing high-quality vector biology and control studies and evaluation of public health insecticides that are operationally relevant. Several onsite mosquito research platforms have been established including experimental huts, a 40-m long semi-field screening enclosure, mosquito insectary, field-laboratory, and living quarters for students and researchers. Field research and assessments ranged from 'basic' investigations on mosquito biology, taxonomy and genetics to more 'applied' studies on responses of mosquitoes to insecticides including repellency, behavioural avoidance and toxicity. In the course of two decades, 51 peer-reviewed articles have been published, and 7 masters and 16 doctoral degrees in Entomology have been awarded to national and international students. Continued support of key national stakeholders will sustain MFRS as a Greater Mekong Subregion centre of excellence and a resource for both insecticide trials and entomological research.
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Affiliation(s)
- Patcharawan Sirisopa
- grid.9723.f0000 0001 0944 049XDepartment of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok, 10900 Thailand
| | - Chutipong Sukkanon
- grid.412867.e0000 0001 0043 6347Department of Medical Technology, School of Allied Health Sciences, Walailak University, Nakhon Si Thammarat, 80160 Thailand
| | - Michael J. Bangs
- grid.9723.f0000 0001 0944 049XDepartment of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok, 10900 Thailand
| | - Sutkhet Nakasathien
- grid.9723.f0000 0001 0944 049XDepartment of Agronomy, Faculty of Agriculture, Kasetsart University, Bangkok, 10900 Thailand
| | - Jeffrey Hii
- grid.1011.10000 0004 0474 1797College of Public Health, Medical and Veterinary Sciences, James Cook University, North Queensland, QLD 4810 Australia
| | - John P. Grieco
- grid.131063.60000 0001 2168 0066Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN USA
| | - Nicole L. Achee
- grid.131063.60000 0001 2168 0066Department of Biological Sciences, Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN USA
| | - Sylvie Manguin
- grid.463853.f0000 0004 0384 4663HSM, Univ. Montpellier, CNRS, IRD, IMT, Montpellier, France
| | - Theeraphap Chareonviriyaphap
- grid.9723.f0000 0001 0944 049XDepartment of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok, 10900 Thailand
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Oumbouke WA, Rowland M, Koffi AA, Alou LPA, Camara S, N'Guessan R. Evaluation of an alpha-cypermethrin + PBO mixture long-lasting insecticidal net VEERALIN® LN against pyrethroid resistant Anopheles gambiae s.s.: an experimental hut trial in M'bé, central Côte d'Ivoire. Parasit Vectors 2019; 12:544. [PMID: 31730481 PMCID: PMC6858630 DOI: 10.1186/s13071-019-3796-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 11/07/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Long-lasting insecticidal nets (LLINs) are the primary method of malaria prevention. However, the widespread resistance to pyrethroids among major malaria vector species represents a significant threat to the continued efficacy of pyrethroid LLIN. Piperonyl butoxide (PBO) is a synergist that inhibits the activity of metabolic enzymes of the cytochrome P450 family known to detoxify insecticides including pyrethroids. Synergist LLIN incorporating PBO and a pyrethroid may provide improved control compared to pyrethroid-only LLIN. METHODS The efficacy of VEERALIN® LN (VKA polymers Pvt Ltd, India), an alpha-cypermethrin PBO synergist net was evaluated in experimental huts in M'bé, central Côte d'Ivoire against wild pyrethroid resistant Anopheles gambiae s.s. Comparison was made with a standard alpha-cypermethrin-treated net (MAGNet® LN, VKA polymers Pvt Ltd, India). Nets were tested unwashed and after 20 standardized washes. RESULTS VEERALIN® LN demonstrated improved efficacy compared to MAGNet® LN against wild free-flying pyrethroid-resistant An. gambiae s.s. Before washing, VEERALIN® LN produced mortality of An. gambiae s.s. (51%) significantly higher than the standard pyrethroid-only net (29%) (P < 0.0001). Although there was a significant reduction in mortality with both LLINs after 20 washes, VEERALIN® LN remained superior in efficacy to MAGNet® LN (38 vs 17%) (P < 0.0001). Blood-feeding was significantly inhibited with both types of insecticide-treated nets relative to the untreated control net (P < 0.0001). Unwashed VEERALIN® LN induced significantly higher blood-feeding inhibition of An. gambiae s.s. (62.6%) compared to MAGNet® LN (35.4%) (P < 0.001). The difference persisted after washing, as there was no indication that either LLIN lost protection against biting or blood-feeding. The level of personal protection derived from the use of VEERALIN® LN was high (87%) compared to MAGNet® LN (66-69%) whether unwashed or washed. The AI content of VEERALIN® LN after 20 washes decreased from 6.75 to 6.03 g/kg for alpha-cypermethrin and from 2.95 to 2.64 g/kg for PBO, corresponding to an overall retention of 89% for each compound. CONCLUSIONS The addition of the synergist PBO to pyrethroid net greatly improved protection and control of pyrethroid-resistant An. gambiae s.s. The pyrethroid-PBO VEERALIN® LN has the potential to reduce transmission in areas compromised by pyrethroid resistance.
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Affiliation(s)
- Welbeck A Oumbouke
- London School of Hygiene and Tropical Medicine, Keppel Street, London, UK. .,Vector Control Product Evaluation Centre (VCPEC)/Institut Pierre Richet, 01 BP 1500, Bouaké, Côte d'Ivoire.
| | - Mark Rowland
- London School of Hygiene and Tropical Medicine, Keppel Street, London, UK
| | - Alphonsine A Koffi
- Vector Control Product Evaluation Centre (VCPEC)/Institut Pierre Richet, 01 BP 1500, Bouaké, Côte d'Ivoire
| | - Ludovic P A Alou
- Vector Control Product Evaluation Centre (VCPEC)/Institut Pierre Richet, 01 BP 1500, Bouaké, Côte d'Ivoire
| | - Soromane Camara
- Vector Control Product Evaluation Centre (VCPEC)/Institut Pierre Richet, 01 BP 1500, Bouaké, Côte d'Ivoire
| | - Raphael N'Guessan
- London School of Hygiene and Tropical Medicine, Keppel Street, London, UK.,Vector Control Product Evaluation Centre (VCPEC)/Institut Pierre Richet, 01 BP 1500, Bouaké, Côte d'Ivoire
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Kweka EJ, Tungu PK, Mahande AM, Mazigo HD, Sayumwe S, Msangi S, Lyaruu L, Waweru J, Kisinza W, Wangai J. Bio-efficacy and wash resistance of MAGNet long-lasting insecticidal net against wild populations of Anopheles funestus in experimental huts in Muheza, Tanzania. Malar J 2019; 18:335. [PMID: 31570107 PMCID: PMC6771101 DOI: 10.1186/s12936-019-2973-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Accepted: 09/24/2019] [Indexed: 11/30/2022] Open
Abstract
Background The decline in malaria cases and vectors is major milestone in fighting against malaria. The efficacy of MAGNet long-lasting insecticidal nets (MAGNet LLIN), an alpha-cypermethrin incorporated long-lasting net, with the target dose ± 25% of 5.8 g active ingredient (AI)/kg (4.35–7.25 g AI/kg) was evaluated in six veranda-trap experimental huts in Muheza, Tanzania against freely flying wild population of Anopheles funestus. Methods MAGNet LLINs were tested against wild, free-flying, host-seeking An. funestus mosquitoes over a period of 6 weeks (total of 36 nights in the huts). MAGNet LLIN efficacy was determined in terms of mosquito mortality, blood-feeding inhibition, deterrence, induced exiting, personal protection, and insecticidal killing over 20 washes according to WHO standardized procedures. Efficacy was compared with reference to a WHOPES recommended approved LLINs (DuraNet) and to a net conventionally treated (CTN) treated with alpha-cypermethrin at WHO-recommended dose and washed to just before cut-off point. The efficacy of MAGNet was evaluated in experimental huts against wild, free-flying, pyrethroid-resistant An. funestus. The WHO-susceptibility method was used to detect resistance in wild Anopheles exposed to 0.75% permethrin. Mosquito mortality, blood-feeding inhibition and personal protection were compared between untreated nets and standard LLINs. Blood-feeding rates were recorded and compared between the 20 times washed; blood-feeding rates between 20 times washed MAGNet LLIN and 20 times washed WHOPES-approved piperonyl butoxide (PBO)/pyrethroid were not statistically different (p > 0.05). Results The results have evidently shown that MAGNet LLIN provides similar blood-feeding inhibition, exophily, mortality, and deterrence to the standard approved LLIN, thus meeting the WHOPES criteria for blood feeding. The significantly high feeding inhibition and personal protection over pyrethroid-resistant An. funestus recorded by both unwashed and 20 times washed MAGNet compared to the unwashed DuraNet, the WHOPES-approved standard pyrethroid-only LLIN provides proof of MAGNet meeting Phase II WHOPES criteria for a LLIN. Conclusion Based on this study, MAGNet has been shown to have a promising impact on protection when 20 times washed against a highly resistant population of An. funestus.
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Affiliation(s)
- Eliningaya J Kweka
- Department of Medical Parasitology and Entomology, School of Medicine, Catholic University of Health and Allied Sciences, P.O. Box 1464, Mwanza, Tanzania. .,Mosquito Section, Division of Livestock and Human Health Disease Vector Control, Tropical Pesticides Research Institute, P.O. Box 3024, Arusha, Tanzania.
| | - Patrick K Tungu
- Amani Medical Research Centre, National Institute for Medical Research, P.O.Box 81, Muheza, Tanga, Tanzania
| | - Aneth M Mahande
- Division of Livestock and Human Health Disease Vector Control, Tropical Pesticides Research Institute, Mabogini Field Station, Moshi, Tanzania
| | - Humphrey D Mazigo
- Mosquito Section, Division of Livestock and Human Health Disease Vector Control, Tropical Pesticides Research Institute, P.O. Box 3024, Arusha, Tanzania
| | - Subira Sayumwe
- Mosquito Section, Division of Livestock and Human Health Disease Vector Control, Tropical Pesticides Research Institute, P.O. Box 3024, Arusha, Tanzania
| | - Shandala Msangi
- Department of Medical Parasitology and Entomology, School of Medicine, Catholic University of Health and Allied Sciences, P.O. Box 1464, Mwanza, Tanzania
| | - Lucile Lyaruu
- Mosquito Section, Division of Livestock and Human Health Disease Vector Control, Tropical Pesticides Research Institute, P.O. Box 3024, Arusha, Tanzania
| | - John Waweru
- PestNet Kenya Ltd, P.O. BOX 51533-00200, Nairobi, Kenya
| | - William Kisinza
- Amani Medical Research Centre, National Institute for Medical Research, P.O.Box 81, Muheza, Tanga, Tanzania
| | - James Wangai
- PestNet Kenya Ltd, P.O. BOX 51533-00200, Nairobi, Kenya
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Gunasekaran K, Sahu SS, Vijayakumar T, Subramanian S, Jambulingam P. Bio-efficacy of LifeNet, a deltamethrin incorporated long-lasting insecticidal net, as assessed in experimental huts against Anopheles fluviatilis, a major malaria vector in east-central India. Acta Trop 2018; 187:151-7. [PMID: 30092223 DOI: 10.1016/j.actatropica.2018.08.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Revised: 08/03/2018] [Accepted: 08/03/2018] [Indexed: 11/24/2022]
Abstract
LifeNet, a deltamethrin incorporated long-lasting insecticidal (polypropylene) net (LLIN), was qualified by the World Health Organization Pesticide Evaluation Scheme (WHOPES) for Phase-II trial in India. The purpose of this trial was to assess the bio-efficacy of unwashed and 20 and 30 times washed LifeNet in comparison to the nets conventionally treated with deltamethrin against the natural population of Anopheles fluviatilis, a major malaria vector, in terms of deterring hut entry, inhibiting blood feeding, inducing exophily and causing mortality. The trial was carried out in six experimental huts constructed at Kandhaguda village in Malkangiri district, Odisha State. The efficacy of unwashed and washed (20 or 30 times) LifeNet was compared with untreated polypropylene and conventionally treated (with deltamethrin) polyester net washed to just before exhaustion or washed 20 times. The study showed a significant reduction of entry (treatment: 1.61-4.78; control: 7.61 per hut) and an increase in exit (50.7-64.4% and 39.1%) of An. fluviatilis in the treated arms compared to the control arm (untreated net) (P < 0.05). Blood feeding rates reduced in treated arms (20.7-68.0%) compared to the control (80.3%) (P < 0.05). Total mortality was significantly higher in LifeNet arms (73.8-98.3%) than the control (2.2%) (P < 0.05). After 30 washes, the active ingredient (AI) retention in LifeNet was 62%. Performance of the three LifeNet arms against the susceptible population of An. fluviatilis met the WHO efficacy criteria of Phase II evaluation for LLINs.
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Agossa FR, Padonou GG, Koukpo CZ, Zola-Sahossi J, Azondekon R, Akuoko OK, Ahoga J, N'dombidje B, Akinro B, Fassinou AJYH, Sezonlin M, Akogbeto MC. Efficacy of a novel mode of action of an indoor residual spraying product, SumiShield® 50WG against susceptible and resistant populations of Anopheles gambiae (s.l.) in Benin, West Africa. Parasit Vectors 2018; 11:293. [PMID: 29747684 PMCID: PMC5946391 DOI: 10.1186/s13071-018-2869-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 04/23/2018] [Indexed: 11/10/2022] Open
Abstract
Background Scale-up of the distribution of long-lasting insecticide-treated bed nets and indoor residual spraying with insecticides over the last decade have contributed to the considerable decrease of malaria morbidity and mortality in sub-Saharan Africa. Due to the increasing pyrethroid resistance intensity and the spread of carbamate resistance in Anopheles gambiae (s.s.) mosquitoes and the limited number of insecticides recommended by the WHO for vector control, alternative insecticide formulations for IRS with long-lasting residual activity are required to sustain the gains obtained in most malaria-endemic countries. Methods SumiShield 50WG (clothianidin 300 mg ai/m2) developed by Sumitomo Chemical was evaluated alongside deltamethrin 25 mg ai/m2 (K-Othrine 250 WG) against a pyrethroid resistant Anopheles gambiae (s.l.) population in experimental huts in Covè, Benin. Residual activity was also tested in cone bioassays with the susceptible An. gambiae “Kisumu” strain and the local wild resistant population. Results The results showed very low toxicity from deltamethrin (mortality rates ranged between 1–40%) against host-seeking resistant Anopheles populations. SumiShield in contrast gave an overall mean mortality of 91.7% at the 120 h observation across the eight- month observation period following spraying. The residual activity measured using cone tests was over the 80% WHO threshold for 24 weeks for resistant wild Anopheles population and 32 weeks for the susceptible strain “Kisumu” after the spraying. Conclusions SumiShield is a good candidate for IRS in areas of permanent malaria transmission and where Anopheles populations are resistant to other conventional insecticides such as pyrethroids. It would be interesting to complete experimental huts studies by assessing the efficacy and residual effect of SumiShield 50WG at community level (small-scale field testing) in an area where vectors are highly resistant to insecticides.
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Affiliation(s)
- Fiacre R Agossa
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Bénin.
| | - Gil G Padonou
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Bénin.,Laboratoire Evolution, Biodiversité des Arthropodes et Assainissement, FAST - UAC, Abomey-Calavi, Bénin
| | - Come Z Koukpo
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Bénin.,Ecole Doctorale Sciences de la Vie et de la Terre, FAST - UAC, Abomey-Calavi, Bénin
| | | | | | - Osei K Akuoko
- Noguchi Memorial Institute for Medical Research University, Accra, Ghana
| | - Juniace Ahoga
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Bénin
| | - Boris N'dombidje
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Bénin
| | - Bruno Akinro
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Bénin
| | - Arsene Jacques Y H Fassinou
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Bénin.,Ecole Doctorale Sciences de la Vie et de la Terre, FAST - UAC, Abomey-Calavi, Bénin
| | - Michel Sezonlin
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Bénin.,Laboratoire Evolution, Biodiversité des Arthropodes et Assainissement, FAST - UAC, Abomey-Calavi, Bénin
| | - Martin C Akogbeto
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Bénin.,Laboratoire Evolution, Biodiversité des Arthropodes et Assainissement, FAST - UAC, Abomey-Calavi, Bénin
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Oumbouke WA, Fongnikin A, Soukou KB, Moore SJ, N'Guessan R. Relative performance of indoor vector control interventions in the Ifakara and the West African experimental huts. Parasit Vectors 2017; 10:432. [PMID: 28927465 PMCID: PMC5606011 DOI: 10.1186/s13071-017-2365-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Accepted: 09/07/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND West African and Ifakara experimental huts are used to evaluate indoor mosquito control interventions, including spatial repellents and insecticides. The two hut types differ in size and design, so a side-by-side comparison was performed to investigate the performance of indoor interventions in the two hut designs using standard entomological outcomes: relative indoor mosquito density (deterrence), exophily (induced exit), blood-feeding and mortality of mosquitoes. METHODS Metofluthrin mosquito coils (0.00625% and 0.0097%) and Olyset® Net vs control nets (untreated, deliberately holed net) were evaluated against pyrethroid-resistant Culex quinquefasciatus in Benin. Four experimental huts were used: two West African hut designs and two Ifakara hut designs. Treatments were rotated among the huts every four nights until each treatment was tested in each hut 52 times. Volunteers rotated between huts nightly. RESULTS The Ifakara huts caught a median of 37 Culex quinquefasciatus/ night, while the West African huts captured a median of 8/ night (rate ratio 3.37, 95% CI: 2.30-4.94, P < 0.0001) and this difference in mosquito entry was similar for Olyset® Net and more pronounced for spatial repellents. Exophily was greater in the Ifakara huts with > 4-fold higher mosquito exit relative to the West African huts (odds ratio 4.18, 95% CI: 3.18-5.51, P < 0.0001), regardless of treatment. While blood-feeding rates were significantly higher in the West African huts, mortality appeared significantly lower for all treatments. CONCLUSIONS The Ifakara hut captured more Cx. quinquefasciatus that could more easily exit into windows and eave traps after failing to blood-feed, compared to the West African hut. The higher mortality rates recorded in the Ifakara huts could be attributable to the greater proportions of Culex mosquitoes exiting and probably dying from starvation, relative to the situation in the West African huts.
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Affiliation(s)
| | | | - Koffi B Soukou
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin
| | - Sarah J Moore
- Environmental Health and Ecological Sciences Thematic Group, Ifakara Health Institute, Bagamoyo Research and Training Centre, Bagamoyo, Tanzania.,Swiss Tropical and Public Health Institute, Socinstr., 574051, Basel, Switzerland.,University of Basel, Petersplatz 1, 4003, Basel, Switzerland
| | - Raphael N'Guessan
- Centre de Recherche Entomologique de Cotonou, Cotonou, Benin.,London School of Hygiene and Tropical Medicine, Keppel Street, WC1E 7HT, London, UK
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Kweka EJ, Lyaruu LJ, Mahande AM. Efficacy of PermaNet® 3.0 and PermaNet® 2.0 nets against laboratory-reared and wild Anopheles gambiae sensu lato populations in northern Tanzania. Infect Dis Poverty 2017; 6:11. [PMID: 28095897 PMCID: PMC5242039 DOI: 10.1186/s40249-016-0220-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 12/15/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Mosquitoes have developed resistance against pyrethroids, the only class of insecticides approved for use on long-lasting insecticidal nets (LLINs). The present study sought to evaluate the efficacy of the pyrethroid synergist PermaNet® 3.0 LLIN versus the pyrethroid-only PermaNet® 2.0 LLIN, in an East African hut design in Lower Moshi, northern Tanzania. In this setting, resistance to pyrethroid insecticides has been identified in Anopheles gambiae mosquitoes. METHODS Standard World Health Organization bioefficacy evaluations were conducted in both laboratory and experimental huts. Experimental hut evaluations were conducted in an area where there was presence of a population of highly pyrethroid-resistant An. arabiensis mosquitoes. All nets used were subjected to cone bioassays and then to experimental hut trials. Mosquito mortality, blood-feeding inhibition and personal protection rate were compared between untreated nets, unwashed LLINs and LLINs that were washed 20 times. RESULTS Both washed and unwashed PermaNet® 2.0 and PermaNet® 3.0 LLINs had knockdown and mortality rates of 100% against a susceptible strain of An. gambiae sensu stricto. The adjusted mortality rate of the wild mosquito population after use of the unwashed PermaNet® 3.0 and PermaNet® 2.0 nets was found to be higher than after use of the washed PermaNet® 2.0 and PermaNet® 3.0 nets. CONCLUSIONS Given the increasing incidence of pyrethroid resistance in An. gambiae mosquitoes in Tanzania, we recommend that consideration is given to its distribution in areas with pyrethroid-resistant malaria vectors within the framework of a national insecticide-resistance management plan.
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Affiliation(s)
- Eliningaya J Kweka
- Tropical Pesticides Research Institute, Division of Livestock and Human Diseases Vector Control, Mosquito Section, P.O. Box 3024, Arusha, Tanzania. .,Department of Medical Parasitology and Entomology, Catholic University of Health and Allied Sciences, P.O. Box 1464, Mwanza, Tanzania.
| | - Lucile J Lyaruu
- Tropical Pesticides Research Institute, Division of Livestock and Human Diseases Vector Control, Mosquito Section, P.O. Box 3024, Arusha, Tanzania
| | - Aneth M Mahande
- Tropical Pesticides Research Institute, Division of Livestock and Human Diseases Vector Control, Mabogini field station, Moshi, Tanzania
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Yeebiyo Y, Dengela D, Tesfaye AG, Anshebo GY, Kolyada L, Wirtz R, Chibsa S, Fornadel C, George K, Belemvire A, Taffese HS, Lucas B. Short persistence of bendiocarb sprayed on pervious walls and its implication for the indoor residual spray program in Ethiopia. Parasit Vectors 2016; 9:266. [PMID: 27151229 PMCID: PMC4858853 DOI: 10.1186/s13071-016-1549-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 04/27/2016] [Indexed: 11/24/2022] Open
Abstract
Background With the emergence and spread of vector resistance to pyrethroids and DDT in Africa, several countries have recently switched or are considering switching to carbamates and/or organophosphates for indoor residual spraying (IRS). However, data collected on the residual life of bendiocarb used for IRS in some areas indicate shorter than expected bio-efficacy. This study evaluated the effect of pH and wall type on the residual life of the carbamates bendiocarb and propoxur as measured by the standard World Health Organization (WHO) cone bioassay test. Methods In phase I of this study, bendiocarb and propoxur were mixed with buffered low pH (pH 4.3) local water and non-buffered high pH (pH 8.0) local water and sprayed on two types of wall surface, mud and dung, in experimental huts. In the six month phase II study, the two insecticides were mixed with high pH local water and sprayed on four different surfaces: painted, dung, mud and mud pre-wetted with water. The residual bio-efficacy of the insecticides was assessed monthly using standard WHO cone bioassay tests. Results In phase I, bendiocarb mixed with high pH water killed more than 80 % of susceptible Anopheles arabiensis mosquitoes for two months on both dung and mud surfaces. On dung surfaces, the 80 % mortality threshold was achieved for three months when the bendiocarb was mixed with low pH water and four months when it was mixed with high pH water. Propoxur lasted longer than bendiocarb on dung surfaces, staying above the 80 % mortality threshold for four and five months when mixed with high and low pH water, respectively. Phase II results also showed that the type of surface sprayed has a significant impact on the bio-efficacy of bendiocarb. Keeping the spray water constant at the same high pH of 8.0, bendiocarb killed 100 % of exposed mosquitoes on impervious painted surfaces for the six months of the study period compared with less than one month on mud surfaces. Conclusions Mixing the insecticides in alkaline water did not reduce the residual bio-efficacy of bendiocarb. However, bendiocarb performed much better on impervious (painted) surfaces than on porous dung or mud ones. Propoxur was less affected by wall type than was bendiocarb. Studies on the interaction between wall materials, soil, humidity, temperature and pH and the residual bio-efficacy of new and existing insecticides are recommended prior to their wide use in IRS.
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Affiliation(s)
- Yemane Yeebiyo
- The President's Malaria Initiative Africa Indoor Residual Spraying Project, Abt Associates, Gerji Road, Sami Building, 1st Floor, Addis Ababa, Ethiopia
| | - Dereje Dengela
- The President's Malaria Initiative Africa Indoor Residual Spraying Project, Abt Associates, 4550 Montgomery Ave., Suite 800 North, Bethesda, MD, 20814, USA.
| | - Alemayehu Getachew Tesfaye
- The President's Malaria Initiative Africa Indoor Residual Spraying Project, Abt Associates, Gerji Road, Sami Building, 1st Floor, Addis Ababa, Ethiopia
| | - Gedeon Yohannes Anshebo
- The President's Malaria Initiative Africa Indoor Residual Spraying Project, Abt Associates, Gerji Road, Sami Building, 1st Floor, Addis Ababa, Ethiopia
| | - Lena Kolyada
- The President's Malaria Initiative Africa Indoor Residual Spraying Project, Abt Associates, 4550 Montgomery Ave., Suite 800 North, Bethesda, MD, 20814, USA
| | - Robert Wirtz
- Entomology Branch, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329-4027, USA
| | - Sheleme Chibsa
- U.S. Agency for International Development (USAID), Entoto Street, Addis Ababa, Ethiopia
| | - Christen Fornadel
- President's Malaria Initiative, United States Agency for International Development, Bureau for Global Health, Office of Health, Infectious Disease & Nutrition, 10082A, 2100 Crystal Drive, Arlington, VA, 22202, USA
| | - Kristen George
- President's Malaria Initiative, United States Agency for International Development, Bureau for Global Health, Office of Health, Infectious Disease & Nutrition, 10082A, 2100 Crystal Drive, Arlington, VA, 22202, USA
| | - Allison Belemvire
- President's Malaria Initiative, United States Agency for International Development, Bureau for Global Health, Office of Health, Infectious Disease & Nutrition, 10082A, 2100 Crystal Drive, Arlington, VA, 22202, USA
| | | | - Bradford Lucas
- The President's Malaria Initiative Africa Indoor Residual Spraying Project, Abt Associates, 4550 Montgomery Ave., Suite 800 North, Bethesda, MD, 20814, USA
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