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Clegban CMY, Camara S, Koffi AA, Ahoua Alou LP, Kabran Kouame JP, Koffi AF, Kouassi PK, Moiroux N, Pennetier C. Evaluation of Yahe ® and Panda ® 2.0 long-lasting insecticidal nets against wild pyrethroid-resistant Anopheles gambiae s.l. from Côte d'Ivoire: an experimental hut trial. Parasit Vectors 2021; 14:347. [PMID: 34210362 PMCID: PMC8247218 DOI: 10.1186/s13071-021-04843-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 06/11/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Long-lasting insecticidal nets (LLINs) have played an important role in reducing the global malaria burden since 2000. They are a core prevention tool used widely by people at risk of malaria. The Vector Control Prequalification mechanism of the Word Health Organization (WHO-Vector Control PQ) established the testing and evaluation guidelines for LLINs before registration for public use. In the present study, two new brands of deltamethrin-impregnated nets (Yahe® LN and Panda® Net 2.0) were evaluated in an experimental hut against wild pyrethroid-resistant Anopheles gambiae s.l. in M'Bé nearby Bouaké, central Côte d'Ivoire. METHODS The performance of Yahe® LN and Panda® Net 2.0 was compared with that of PermaNet 2.0, conventionally treated nets (CTN), and untreated net to assess the blood-feeding inhibition, deterrence, induced exophily, and mortality. RESULTS Cone bioassay results showed that Panda® Net 2.0, PermaNet 2.0 and Yahe® LN (both unwashed and washed 20 times) induced > 95% knockdown or > 80% mortality of the susceptible Anopheles gambiae Kisumu strain. With the pyrethroid-resistant M'Bé strain, mortality rate for all treated nets did not exceed 70%. There was a significant reduction in entry and blood feeding (p < 0.05) and an increase in exophily and mortality rates (p < 0.05) with all treatments compared to untreated nets, except the CTNs. However, the personal protection induced by these treated nets decreased significantly after 20 washes. The performance of Panda® Net 2.0 was equal to PermaNet® 2.0 in terms of inhibiting blood feeding, but better than PermaNet® 2.0 in terms of mortality. CONCLUSION This study showed that Yahe® LN and Panda® Net 2.0 met the WHO Pesticide Evaluation Scheme (WHOPES) criteria to undergo phase III trial at the community level. Due to an increasing spread and development of pyrethroid resistance in malaria vectors, control of malaria transmission must evolve into an integrated vector management relying on a large variety of efficient control tools.
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Affiliation(s)
- Cyntia-Muriel Y Clegban
- Institut Pierre Richet/Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire. .,Université Félix Houphouët-Boigny, Abidjan, Côte d'Ivoire. .,MIVEGEC, Univ Montpellier, CNRS, IRD, Montpellier, France.
| | - Soromane Camara
- Institut Pierre Richet/Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire.,Université Félix Houphouët-Boigny, Abidjan, Côte d'Ivoire.,MIVEGEC, Univ Montpellier, CNRS, IRD, Montpellier, France
| | - A Alphonsine Koffi
- Institut Pierre Richet/Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire
| | - Ludovic P Ahoua Alou
- Institut Pierre Richet/Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire
| | | | - A Fernand Koffi
- Institut Pierre Richet/Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire
| | | | | | - Cédric Pennetier
- Institut Pierre Richet/Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire.,MIVEGEC, Univ Montpellier, CNRS, IRD, Montpellier, France
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Deguenon JM, Azondekon R, Agossa FR, Padonou GG, Anagonou R, Ahoga J, N’dombidje B, Akinro B, Stewart DA, Wang B, Gittins D, Tihomirov L, Apperson CS, McCord MG, Akogbeto MC, Roe RM. Imergard TMWP: A Non-Chemical Alternative for an Indoor Residual Spray, Effective against Pyrethroid-Resistant Anopheles gambiae (s.l.) in Africa. INSECTS 2020; 11:E322. [PMID: 32456154 PMCID: PMC7290382 DOI: 10.3390/insects11050322] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 04/29/2020] [Accepted: 05/18/2020] [Indexed: 11/17/2022]
Abstract
Malaria is the deadliest mosquito-borne disease and kills predominantly people in sub-Saharan Africa (SSA). The now widespread mosquito resistance to pyrethroids, with rapidly growing resistance to other insecticide classes recommended by the World Health Organization (WHO), may overturn the successes gained in mosquito control in recent years. It is of utmost importance to search for new, inexpensive, and safe alternatives, with new modes of action, that might improve the efficacy of current insecticides. The efficacy of a novel mechanical insecticidal mineral derived from volcanic rock, ImergardTMWP, was investigated to determine its efficacy as a stand-alone residual wall spray and as a mixture with deltamethrin (K-Othrine® Polyzone) in experimental huts in Cove, Benin. The evaluation was conducted with susceptible (Kisumu) and wild-type Anopheles gambiae (s.l.). Deltamethrin applied alone demonstrated 40-45% mortality (at 72 h post-exposure) during the first four months, which declined to 25% at six months for wild An. gambiae from Cove. ImergardTMWP alone and mixed with deltamethrin, under the same assay conditions, produced 79-82% and 73-81% mortality, respectively, during the same six-month period. ImergardTMWP met the 80% WHO bio-efficacy threshold for residual activity for the first five months with 78% residual activity at six months. ImergardTMWP can be used as a mixture with chemical insecticides or as a stand-alone pesticide for mosquito control in Africa.
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Affiliation(s)
- Jean M. Deguenon
- Department of Entomology and Plant Pathology, Campus Box 7647, 3230 Ligon Street, North Carolina State University, Raleigh, NC 27695, USA; (J.M.D.); (C.S.A.)
| | - Roseric Azondekon
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou 06BP2604, Benin; (R.A.); (F.R.A.); (G.G.P.); (R.A.); (J.A.); (B.N.); (B.A.); (M.C.A.)
| | - Fiacre R. Agossa
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou 06BP2604, Benin; (R.A.); (F.R.A.); (G.G.P.); (R.A.); (J.A.); (B.N.); (B.A.); (M.C.A.)
| | - Gil G. Padonou
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou 06BP2604, Benin; (R.A.); (F.R.A.); (G.G.P.); (R.A.); (J.A.); (B.N.); (B.A.); (M.C.A.)
| | - Rodrigue Anagonou
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou 06BP2604, Benin; (R.A.); (F.R.A.); (G.G.P.); (R.A.); (J.A.); (B.N.); (B.A.); (M.C.A.)
| | - Juniace Ahoga
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou 06BP2604, Benin; (R.A.); (F.R.A.); (G.G.P.); (R.A.); (J.A.); (B.N.); (B.A.); (M.C.A.)
| | - Boris N’dombidje
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou 06BP2604, Benin; (R.A.); (F.R.A.); (G.G.P.); (R.A.); (J.A.); (B.N.); (B.A.); (M.C.A.)
| | - Bruno Akinro
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou 06BP2604, Benin; (R.A.); (F.R.A.); (G.G.P.); (R.A.); (J.A.); (B.N.); (B.A.); (M.C.A.)
| | - David A. Stewart
- Imerys Filtration Minerals, Inc., Roswell, GA 30076, USA; (D.A.S.); (B.W.); (D.G.); (L.T.)
| | - Bo Wang
- Imerys Filtration Minerals, Inc., Roswell, GA 30076, USA; (D.A.S.); (B.W.); (D.G.); (L.T.)
| | - David Gittins
- Imerys Filtration Minerals, Inc., Roswell, GA 30076, USA; (D.A.S.); (B.W.); (D.G.); (L.T.)
| | - Larissa Tihomirov
- Imerys Filtration Minerals, Inc., Roswell, GA 30076, USA; (D.A.S.); (B.W.); (D.G.); (L.T.)
| | - Charles S. Apperson
- Department of Entomology and Plant Pathology, Campus Box 7647, 3230 Ligon Street, North Carolina State University, Raleigh, NC 27695, USA; (J.M.D.); (C.S.A.)
| | - Marian G. McCord
- College of Natural Resources, Campus Box 8001, 2820 Faucette Drive, North Carolina State University, Raleigh, NC 27695, USA;
| | - Martin C. Akogbeto
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou 06BP2604, Benin; (R.A.); (F.R.A.); (G.G.P.); (R.A.); (J.A.); (B.N.); (B.A.); (M.C.A.)
| | - R. Michael Roe
- Department of Entomology and Plant Pathology, Campus Box 7647, 3230 Ligon Street, North Carolina State University, Raleigh, NC 27695, USA; (J.M.D.); (C.S.A.)
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Camara S, Ahoua Alou LP, Koffi AA, Clegban YCM, Kabran JP, Koffi FM, Koffi K, Pennetier C. Efficacy of Interceptor ® G2, a new long-lasting insecticidal net against wild pyrethroid-resistant Anopheles gambiae s.s. from Côte d'Ivoire: a semi-field trial. ACTA ACUST UNITED AC 2018; 25:42. [PMID: 30088473 PMCID: PMC6082037 DOI: 10.1051/parasite/2018042] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Accepted: 07/19/2018] [Indexed: 11/17/2022]
Abstract
Background: The widespread insecticide resistance in malaria vector populations is a serious threat to the efficacy of vector control tools. As a result, the World Health Organization (WHO) supports the development of alternative tools that combine several insecticides with the aim of improving vector control and the management of insecticide resistance. In the present study, a long-lasting insecticidal net treated with a mixture of chlorfenapyr and alphacypermethrin was evaluated against wild pyrethroid-resistant Anopheles gambiae s.s in M’bé, Côte d’Ivoire. Centers for Disease Control and Prevention (CDC) bottle tests were carried out with resistant An. gambiae s.s. of M’bé and the susceptible strain, to assess the resistance level to chlorfenapyr and alphacypermethrin. Results: CDC bottle bioassays revealed a high level of resistance of An. gambiae s.s. population from M’bé to alphacypermethrin, whereas they revealed low resistance to chlorfenapyr. In experimental huts, Interceptor® G2 that was unwashed or washed 20 times killed 87% and 82% of An. gambiae s.s., respectively, whereas Interceptor® LN that was either unwashed or washed 20 times killed only about 10% of the mosquitoes. The blood-feeding inhibition induced by Interceptor® was not significantly different compared to untreated nets, whereas Interceptor® G2 that was unwashed or washed 20 times induced 42% and 34% inhibition of blood-feeding, respectively. Conclusion: Interceptor® G2 met the WHOPES criteria to undergo a phase III study. Investigation of its efficacy at a community level and the conduct of randomized controlled trials dealing with epidemiological outputs are warranted in order to study the potential of Interceptor® G2 to better protect communities.
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Affiliation(s)
- Soromane Camara
- Institut Pierre Richet/Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire - Université Félix Houphouët-Boigny, Abidjan, Côte d'Ivoire - Institut de Recherche pour le Développement (IRD), Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle (MIVEGEC), UMR 224, Bouaké, Côte d'Ivoire
| | | | | | - Yao Cyntia Muriel Clegban
- Institut Pierre Richet/Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire - Université Félix Houphouët-Boigny, Abidjan, Côte d'Ivoire
| | - Jean-Paul Kabran
- Institut Pierre Richet/Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire
| | - Fernand Mathieu Koffi
- Institut Pierre Richet/Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire
| | - Kouakou Koffi
- Université Félix Houphouët-Boigny, Abidjan, Côte d'Ivoire
| | - Cédric Pennetier
- Institut Pierre Richet/Institut National de Santé Publique (INSP), Bouaké, Côte d'Ivoire - Institut de Recherche pour le Développement (IRD), Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle (MIVEGEC), UMR 224, Bouaké, Côte d'Ivoire
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Ketoh GK, Ahadji-Dabla KM, Chabi J, Amoudji AD, Apetogbo GY, Awokou F, Glitho IA. Efficacy of two PBO long lasting insecticidal nets against natural populations of Anopheles gambiae s.l. in experimental huts, Kolokopé, Togo. PLoS One 2018; 13:e0192492. [PMID: 29995894 PMCID: PMC6040683 DOI: 10.1371/journal.pone.0192492] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 01/24/2018] [Indexed: 11/18/2022] Open
Abstract
LLINs containing an insecticide plus the synergist, piperonyl butoxide (PBO) have been designed for increased efficacy against pyrethroid-resistant malaria vectors. In this study, two LLINs with PBO, PermaNet® 3.0 and Olyset® Plus, and a pyrethroid-only LLIN, Yorkool®, were evaluated in experimental huts against a free-flying, wild population of Anopheles gambiae s.l. in Kolokopé, a cotton cultivated area of Togo. WHO susceptibility tube tests and subsequent molecular assays determine the An. gambiae s.l. populations to be resistant to pyrethroids and DDT with both target site kdr and metabolic resistance mechanisms involved in the resistance observed. Anopheles gambiae s.s. and An. coluzzi were present in sympatry though the kdr (L1014F) mutation was observed at a higher frequency in An. gambiae s.s. The experimental hut results showed that both PermaNet® 3.0 and Olyset® Plus nets induced similar levels of deterrence, exophily, and reduced blood feeding rate against wild An. gambiae s.l. in contrast to the pyrethroid only LLIN, Yorkool®. The proportion of wild An. gambiae s.l. killed by unwashed PermaNet® 3.0 was significantly higher than unwashed Olyset® Plus (corrected mortality 80.5% compared to 66.6%). Similar blood feeding inhibition rates were observed for unwashed PermaNet® 3.0 and Olyset® Plus; however, PermaNet® 3.0 washed 20 times demonstrated significantly higher blood feeding inhibition rate than Olyset® Plus washed 20 times (91.1% compared with 85.6% respectively). Yorkool® performed the worst for all the parameters evaluated. In an area of pyrethroid resistance of An. gambiae s.l involving kdr target site and metabolic resistance mechanisms, LLINs with PBO can provide additional protection in terms of reduction in blood feeding and increase in mosquito mortality compared to a pyrethroid-only net, and should be considered in malaria vector control strategies.
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Affiliation(s)
- Guillaume K. Ketoh
- Insect Pest and Insect Vector Management/Ecotoxicology, Unité de Recherche en Ecotoxicologie (URET), Laboratoire d’Entomologie Appliquée (LEA), Faculté des Sciences, Université de Lomé, Lomé, Togo
| | - Koffi M. Ahadji-Dabla
- Insect Pest and Insect Vector Management/Ecotoxicology, Unité de Recherche en Ecotoxicologie (URET), Laboratoire d’Entomologie Appliquée (LEA), Faculté des Sciences, Université de Lomé, Lomé, Togo
- * E-mail:
| | - Joseph Chabi
- Noguchi Memorial Institute for Medical Research (NMIMR), University of Ghana, Legon, Accra, Ghana
| | - Adjovi D. Amoudji
- Insect Pest and Insect Vector Management/Ecotoxicology, Unité de Recherche en Ecotoxicologie (URET), Laboratoire d’Entomologie Appliquée (LEA), Faculté des Sciences, Université de Lomé, Lomé, Togo
| | - Georges Y. Apetogbo
- Insect Pest and Insect Vector Management/Ecotoxicology, Unité de Recherche en Ecotoxicologie (URET), Laboratoire d’Entomologie Appliquée (LEA), Faculté des Sciences, Université de Lomé, Lomé, Togo
| | - Fantchè Awokou
- Programme National de Lutte contre le Paludisme (PNLP), Ministère de la Santé, Lomé, Togo
| | - Isabelle A. Glitho
- Insect Pest and Insect Vector Management/Ecotoxicology, Unité de Recherche en Ecotoxicologie (URET), Laboratoire d’Entomologie Appliquée (LEA), Faculté des Sciences, Université de Lomé, Lomé, Togo
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Gore-Langton GR, Mungai J, Alenwi N, Abagira A, Bicknell OM, Harrison RE, Hassan FA, Munga S, Eves K, Juma E, Allan R. Investigating a Non-Mesh Mosquito Net Among Outdoor Sleeping Nomadic Communities in Kenya. Am J Trop Med Hyg 2015; 93:1002-1009. [PMID: 26416107 PMCID: PMC4703291 DOI: 10.4269/ajtmh.14-0458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 06/15/2015] [Indexed: 11/17/2022] Open
Abstract
Rising reports of exophagic malaria vectors make even more pressing the need for alternatives to traditional, mesh, long-lasting insecticidal nets (LLINs) designed for indoor sleeping and often inadequate in the protection of outdoor-sleeping populations. This study tests and evaluates the retention, utilization, and durability of novel, non-mesh nets designed for outdoor use. Longitudinal, cross-sectional surveys were conducted, the physical condition of nets was assessed, and bio-efficacy and insecticide content were tested. At 22 months, retention was 98.0%; 97.1% of nets fell within the World Health Organization (WHO) category of being in “good” condition; none were in the “torn” category. At 18 months post-distribution, 100% of nets had at least WHO Pesticide Evaluation Scheme (WHOPES)-acceptable levels of insecticide, this proportion was 66.7% at 22 months. This novel mosquito net has the potential to provide a durable and context-specific tool to prevent malaria among traditionally hard-to-protect and highly vulnerable populations.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Richard Allan
- *Address correspondence to Richard Allan, The MENTOR Initiative, The Pinnacle Central Court Station Way, Crawley RH 10I JH, United Kingdom. E-mail:
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Gryseels C, Peeters Grietens K, Dierickx S, Xuan XN, Uk S, Bannister-Tyrrell M, Trienekens S, Ribera JM, Hausmann-Muela S, Gerrets R, D'Alessandro U, Sochantha T, Coosemans M, Erhart A. High Mobility and Low Use of Malaria Preventive Measures Among the Jarai Male Youth Along the Cambodia-Vietnam Border. Am J Trop Med Hyg 2015; 93:810-818. [PMID: 26283747 PMCID: PMC4596604 DOI: 10.4269/ajtmh.15-0259] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 05/29/2015] [Indexed: 11/07/2022] Open
Abstract
Malaria control along the Vietnam-Cambodia border presents a challenge for both countries' malaria elimination targets as the region is forested, inhabited by ethnic minority populations, and potentially characterized by early and outdoor malaria transmission. A mixed methods study assessed the vulnerability to malaria among the Jarai population living on both sides of the border in the provinces of Ratanakiri (Cambodia) and Gia Lai (Vietnam). A qualitative study generated preliminary hypotheses that were quantified in two surveys, one targeting youth (N = 498) and the other household leaders (N = 449). Jarai male youth, especially in Cambodia, had lower uptake of preventive measures (57.4%) and more often stayed overnight in the deep forest (35.8%) compared with the female youth and the adult population. Among male youth, a high-risk subgroup was identified that regularly slept at friends' homes or outdoors, who had fewer bed nets (32.5%) that were torn more often (77.8%). The vulnerability of Jarai youth to malaria could be attributed to the transitional character of youth itself, implying less fixed sleeping arrangements in nonpermanent spaces or non-bed sites. Additional tools such as long-lasting hammock nets could be suitable as they are in line with current practices.
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Affiliation(s)
- Charlotte Gryseels
- *Address correspondence to Charlotte Gryseels, Medical Anthropology Unit, Institute of Tropical Medicine, Nationalestraat 155, 2000 Antwerp, Belgium. E-mail:
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Kitau J, Oxborough R, Kaye A, Chen-Hussey V, Isaacs E, Matowo J, Kaur H, Magesa SM, Mosha F, Rowland M, Logan J. Laboratory and experimental hut evaluation of a long-lasting insecticide treated blanket for protection against mosquitoes. Parasit Vectors 2014; 7:129. [PMID: 24679345 PMCID: PMC3973002 DOI: 10.1186/1756-3305-7-129] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 03/07/2014] [Indexed: 11/23/2022] Open
Abstract
Background Long-lasting insecticide treated blankets (LLIBs) may provide additional protection against malaria where use of long lasting insecticidal nets (LLIN) is low or impractical such as in disaster or emergency situations. Methods Initial efficacy testing of a new candidate LLIB was carried out at LSHTM and KCMUCo, before and after washing, in cone and ball bioassays and arm-in-cage tests against pyrethroid susceptible Anopheles gambiae. A small scale field trial was conducted using veranda-trap experimental huts in northern Tanzania against wild An. arabiensis and Culex quinquefasciatus mosquitoes. Treatments included unwashed and 5 times washed permethrin treated LLIB and blankets hand-treated with permethrin (ITB), untreated blankets, and a holed unwashed Olyset net. Results Cone test mortality was 75% for LLIB when unwashed, but decreased to 32% after 5 washes and <10% after 10 washes. In arm-in-cage tests protection against biting was 100% for LLIBs regardless of the number of washes while reduction in landings was 79% when unwashed, 75% after 5 washes, but declined to 41% after 10 and 33% after 20 washes. In ball bioassays using pyrethroid resistant An. arabiensis, mortality was low in all treatments (<35%) and there was no significant difference in mortality between Olyset net, LLIB or ITB (p > 0.05). Percentage mortality of An. arabiensis in huts with LLIB unwashed (26%) was not statistically different to Olyset net (31%, p = 0.5). The 5 times washed LLIB reduced blood-feeding by 49% which was equivalent to Olyset net (p > 0.086). There was no significant difference in percentage blood-feeding between LLIB and ITB unwashed or 5 times washed (p = 0.147 and p = 0.346 respectively). The 5 times washed LLIB reduced blood-feeding of Culex quinquefasciatus by 40%, although the Olyset provided the greatest protection with 85% inhibition. ELISA analysis of a sub-sample of blood fed mosquitoes showed that not all had fed on humans in the huts, therefore blood-feeding inhibition may have been underestimated. Conclusions This trial demonstrated the potential of LLIBs to provide substantial personal protection even against pyrethroid resistant mosquitoes. LLIBs may prove particularly useful where LLINs are unsuitable or net usage is low.
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Affiliation(s)
- Jovin Kitau
- Department of Entomology and Parasitology, Kilimanjaro Christian Medical University College (KCMUCo), Moshi, Tanzania.
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Pennetier C, Bouraima A, Chandre F, Piameu M, Etang J, Rossignol M, Sidick I, Zogo B, Lacroix MN, Yadav R, Pigeon O, Corbel1 V. Efficacy of Olyset® Plus, a new long-lasting insecticidal net incorporating permethrin and piperonyl-butoxide against multi-resistant malaria vectors [corrected]. PLoS One 2013; 8:e75134. [PMID: 24116029 PMCID: PMC3792972 DOI: 10.1371/journal.pone.0075134] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2013] [Accepted: 08/07/2013] [Indexed: 12/22/2022] Open
Abstract
Due to the rapid extension of pyrethroid resistance in malaria vectors worldwide, manufacturers are developing new vector control tools including insecticide mixtures containing at least two active ingredients with different mode of action as part of insecticide resistance management. Olyset® Plus is a new long-lasting insecticidal net (LLIN) incorporating permethrin and a synergist, piperonyl butoxide (PBO), into its fibres in order to counteract metabolic-based pyrethroid resistance of mosquitoes. In this study, we evaluated the efficacy of Olyset® Plus both in laboratory and field against susceptible and multi-resistant malaria vectors and compared with Olyset Net, which is a permethrin incorporated into polyethylene net. In laboratory, Olyset® Plus performed better than Olyset® Net against susceptible Anopheles gambiae strain with a 2-day regeneration time owing to an improved permethrin bleeding rate with the new incorporation technology. It also performed better than Olyset® Net against multiple resistant populations of An. gambiae in experimental hut trials in West Africa. Moreover, the present study showed evidence for a benefit of incorporating a synergist, PBO, with a pyrethroid insecticide into mosquito netting. These results need to be further validated in a large-scale field trial to assess the durability and acceptability of this new tool for malaria vector control.
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Affiliation(s)
- Cédric Pennetier
- Institut de Recherche pour le Développement (IRD), Maladies Infectieuses et Vecteurs, Ecologie, Genetique, Evolution et Controle (MIVEGEC), UM1-UM2-CNRS 5290 IRD 224, Cotonou, Bénin
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Bénin
| | - Aziz Bouraima
- Institut de Recherche pour le Développement (IRD), Maladies Infectieuses et Vecteurs, Ecologie, Genetique, Evolution et Controle (MIVEGEC), UM1-UM2-CNRS 5290 IRD 224, Cotonou, Bénin
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Bénin
| | - Fabrice Chandre
- Institut de Recherche pour le Développement (IRD), Maladies Infectieuses et Vecteurs, Ecologie, Genetique, Evolution et Controle (MIVEGEC), UM1-UM2-CNRS 5290 IRD 224, Montpellier, France
| | - Michael Piameu
- Laboratory of Medical Entomology, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
- Centre Supérieur des Sciences de la Santé, Université Catholique d’Afrique Centrale, Yaoundé, Cameroon
| | - Josiane Etang
- Laboratory of Medical Entomology, Organisation de Coordination pour la lutte contre les Endémies en Afrique Centrale (OCEAC), Yaoundé, Cameroon
- Faculty of Medicine and Pharmaceutical Sciences, The University of Douala, Douala, Cameroon
| | - Marie Rossignol
- Institut de Recherche pour le Développement (IRD), Maladies Infectieuses et Vecteurs, Ecologie, Genetique, Evolution et Controle (MIVEGEC), UM1-UM2-CNRS 5290 IRD 224, Montpellier, France
| | - Ibrahim Sidick
- Institut de Recherche pour le Développement (IRD), Maladies Infectieuses et Vecteurs, Ecologie, Genetique, Evolution et Controle (MIVEGEC), UM1-UM2-CNRS 5290 IRD 224, Cotonou, Bénin
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Bénin
| | - Barnabas Zogo
- Institut de Recherche pour le Développement (IRD), Maladies Infectieuses et Vecteurs, Ecologie, Genetique, Evolution et Controle (MIVEGEC), UM1-UM2-CNRS 5290 IRD 224, Cotonou, Bénin
- Centre de Recherche Entomologique de Cotonou (CREC), Cotonou, Bénin
| | - Marie-Noëlle Lacroix
- Institut de Recherche pour le Développement (IRD), Maladies Infectieuses et Vecteurs, Ecologie, Genetique, Evolution et Controle (MIVEGEC), UM1-UM2-CNRS 5290 IRD 224, Montpellier, France
| | - Rajpal Yadav
- Vector Ecology and Management, Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - Olivier Pigeon
- Walloon Agricultural Research Centre (CRA-W), Agriculture and Natural Environment Department, Plant Protection Products and Biocides Physico-chemistry and Residues Unit, Gembloux, Belgium
| | - Vincent Corbel1
- Department of Entomology, Faculty of Agriculture, Kasetsart University, Bangkok, Thailand
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Grietens KP, Xuan XN, Ribera J, Duc TN, Bortel WV, Ba NT, Van KP, Xuan HL, D'Alessandro U, Erhart A. Social determinants of long lasting insecticidal hammock use among the Ra-glai ethnic minority in Vietnam: implications for forest malaria control. PLoS One 2012; 7:e29991. [PMID: 22253852 PMCID: PMC3257264 DOI: 10.1371/journal.pone.0029991] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Accepted: 12/09/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Long-lasting insecticidal hammocks (LLIHs) are being evaluated as an additional malaria prevention tool in settings where standard control strategies have a limited impact. This is the case among the Ra-glai ethnic minority communities of Ninh Thuan, one of the forested and mountainous provinces of Central Vietnam where malaria morbidity persist due to the sylvatic nature of the main malaria vector An. dirus and the dependence of the population on the forest for subsistence--as is the case for many impoverished ethnic minorities in Southeast Asia. METHODS A social science study was carried out ancillary to a community-based cluster randomized trial on the effectiveness of LLIHs to control forest malaria. The social science research strategy consisted of a mixed methods study triangulating qualitative data from focused ethnography and quantitative data collected during a malariometric cross-sectional survey on a random sample of 2,045 study participants. RESULTS To meet work requirements during the labor intensive malaria transmission and rainy season, Ra-glai slash and burn farmers combine living in government supported villages along the road with a second home at their fields located in the forest. LLIH use was evaluated in both locations. During daytime, LLIH use at village level was reported by 69.3% of all respondents, and in forest fields this was 73.2%. In the evening, 54.1% used the LLIHs in the villages, while at the fields this was 20.7%. At night, LLIH use was minimal, regardless of the location (village 4.4%; forest 6.4%). DISCUSSION Despite the free distribution of insecticide-treated nets (ITNs) and LLIHs, around half the local population remains largely unprotected when sleeping in their forest plot huts. In order to tackle forest malaria more effectively, control policies should explicitly target forest fields where ethnic minority farmers are more vulnerable to malaria.
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Howard AF, N'guessan R, Koenraadt CJ, Asidi A, Farenhorst M, Akogbéto M, Thomas MB, Knols BG, Takken W. The entomopathogenic fungus Beauveria bassiana reduces instantaneous blood feeding in wild multi-insecticide-resistant Culex quinquefasciatus mosquitoes in Benin, West Africa. Parasit Vectors 2010; 3:87. [PMID: 20843321 PMCID: PMC2946288 DOI: 10.1186/1756-3305-3-87] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2010] [Accepted: 09/15/2010] [Indexed: 02/01/2023] Open
Abstract
Background Mosquito-borne diseases are still a major health risk in many developing countries, and the emergence of multi-insecticide-resistant mosquitoes is threatening the future of vector control. Therefore, new tools that can manage resistant mosquitoes are required. Laboratory studies show that entomopathogenic fungi can kill insecticide-resistant malaria vectors but this needs to be verified in the field. Methods The present study investigated whether these fungi will be effective at infecting, killing and/or modifying the behaviour of wild multi-insecticide-resistant West African mosquitoes. The entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana were separately applied to white polyester window netting and used in combination with either a permethrin-treated or untreated bednet in an experimental hut trial. Untreated nets were used because we wanted to test the effect of fungus alone and in combination with an insecticide to examine any potential additive or synergistic effects. Results In total, 1125 female mosquitoes were collected during the hut trial, mainly Culex quinquefasciatus Say. Unfortunately, not enough wild Anopheles gambiae Giles were collected to allow the effect the fungi may have on this malaria vector to be analysed. None of the treatment combinations caused significantly increased mortality of Cx. quinquefasciatus when compared to the control hut. The only significant behaviour modification found was a reduction in blood feeding by Cx. quinquefasciatus, caused by the permethrin and B. bassiana treatments, although no additive effect was seen in the B. bassiana and permethrin combination treatment. Beauveria bassiana did not repel blood foraging mosquitoes either in the laboratory or field. Conclusions This is the first time that an entomopathogenic fungus has been shown to reduce blood feeding of wild mosquitoes. This behaviour modification indicates that B. bassiana could potentially be a new mosquito control tool effective at reducing disease transmission, although further field work in areas with filariasis transmission should be carried out to verify this. In addition, work targeting malaria vector mosquitoes should be carried out to see if these mosquitoes manifest the same behaviour modification after infection with B. bassiana conidia.
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Affiliation(s)
- Annabel Fv Howard
- Laboratory of Entomology, Wageningen University and Research Centre, P,O, Box 8031, 6700 EH Wageningen, The Netherlands.
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Djènontin A, Chabi J, Baldet T, Irish S, Pennetier C, Hougard JM, Corbel V, Akogbéto M, Chandre F. Managing insecticide resistance in malaria vectors by combining carbamate-treated plastic wall sheeting and pyrethroid-treated bed nets. Malar J 2009; 8:233. [PMID: 19843332 PMCID: PMC2776024 DOI: 10.1186/1475-2875-8-233] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2009] [Accepted: 10/20/2009] [Indexed: 11/10/2022] Open
Abstract
Background Pyrethroid resistance is now widespread in Anopheles gambiae, the major vector for malaria in sub-Saharan Africa. This resistance may compromise malaria vector control strategies that are currently in use in endemic areas. In this context, a new tool for management of resistant mosquitoes based on the combination of a pyrethroid-treated bed net and carbamate-treated plastic sheeting was developed. Methods In the laboratory, the insecticidal activity and wash resistance of four carbamate-treated materials: a cotton/polyester blend, a polyvinyl chloride tarpaulin, a cotton/polyester blend covered on one side with polyurethane, and a mesh of polypropylene fibres was tested. These materials were treated with bendiocarb at 100 mg/m2 and 200 mg/m2 with and without a binding resin to find the best combination for field studies. Secondly, experimental hut trials were performed in southern Benin to test the efficacy of the combined use of a pyrethroid-treated bed net and the carbamate-treated material that was the most wash-resistant against wild populations of pyrethroid-resistant An. gambiae and Culex quinquefasciatus. Results Material made of polypropylene mesh (PPW) provided the best wash resistance (up to 10 washes), regardless of the insecticide dose, the type of washing, or the presence or absence of the binding resin. The experimental hut trial showed that the combination of carbamate-treated PPW and a pyrethroid-treated bed net was extremely effective in terms of mortality and inhibition of blood feeding of pyrethroid-resistant An. gambiae. This efficacy was found to be proportional to the total surface of the walls. This combination showed a moderate effect against wild populations of Cx. quinquefasciatus, which were strongly resistant to pyrethroid. Conclusion These preliminary results should be confirmed, including evaluation of entomological, parasitological, and clinical parameters. Selective pressure on resistance mechanisms within the vector population, effects on other pest insects, and the acceptability of this management strategy in the community also need to be evaluated.
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Long-Lasting Insecticidal Hammocks for controlling forest malaria: a community-based trial in a rural area of central Vietnam. PLoS One 2009; 4:e7369. [PMID: 19809502 PMCID: PMC2752990 DOI: 10.1371/journal.pone.0007369] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2009] [Accepted: 09/08/2009] [Indexed: 11/19/2022] Open
Abstract
Background In Vietnam, malaria remains a problem in some remote areas located along its international borders and in the central highlands, partly due to the bionomics of the local vector, mainly found in forested areas and less vulnerable to standard control measures. Long Lasting Insecticidal Hammocks (LLIH), a tailored and user-friendly tool for forest workers, may further contribute in reducing the malaria burden. Their effectiveness was tested in a large community-based intervention trial carried out in Ninh Thuan province in Central Vietnam. Methods and Findings Thirty villages (population 18,646) were assembled in 20 clusters (1,000 individuals per cluster) that were randomly allocated to either the intervention or control group (no LLIH) after stratification according to the pre-intervention P. falciparum antibody prevalence (<30%; ≥30%). LLIH were distributed to the intervention group in December 2004. For the following 2 years, the incidence of clinical malaria and the prevalence of infection were determined by passive case detection at community level and by bi-annual malariometric surveys. A 2-fold larger effect on malaria incidence in the intervention as compared to the control group was observed. Similarly, malaria prevalence decreased more substantially in the intervention (1.6-fold greater reduction) than in the control group. Both for incidence and prevalence, a stronger and earlier effect of the intervention was observed in the high endemicity stratum. The number of malaria cases and infections averted by the intervention overall was estimated at 10.5 per 1,000 persons and 5.6/100 individuals, respectively, for the last half of 2006. In the high endemicity stratum, the impact was much higher, i.e. 29/1000 malaria cases and 15.7 infections/100 individuals averted. Conclusions LLIH reduced malaria incidence and prevalence in this remote and forested area of Central Vietnam. As the targets of the newly-launched Global Malaria Action Plan include the 75% reduction of the global malaria cases by 2015 and eventually the elimination/eradication of malaria in the long term, LLIH may represent an additional tool for reaching such objectives, particularly in high endemicity areas where standard control tools have a modest impact, such as in remote and forested areas of Southeast Asia and possibly South America. Trial Registration ClinicalTrials.gov NCT00853281
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