{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,3]],"date-time":"2026-06-03T15:09:23Z","timestamp":1780499363839,"version":"3.54.1"},"reference-count":50,"publisher":"American Society of Tropical Medicine and Hygiene","issue":"6","license":[{"start":{"date-parts":[[2026,6,3]],"date-time":"2026-06-03T00:00:00Z","timestamp":1780444800000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,6,3]]},"abstract":"<jats:title>ABSTRACT.<\/jats:title>\n                  <jats:p>\n                    In response to rising insecticide resistance among malaria vector species, countries are implementing long-lasting insecticide treated nets (LLINs) coformulated with piperonyl butoxide (PBO), which can restore susceptibility to pyrethroid-based nets. In mid-2021, Kenya National Malaria Program rolled out PBO-LLINs in Bungoma County. We evaluated the susceptibility of wild-collected vectors to new versus used PBO-LLINs using the WHO cone bioassays. Results were confirmed with the WHO susceptibility assay. A total of 2,020 female\n                    <jats:italic>Anopheles<\/jats:italic>\n                    were tested, of which 1,480 were wild-collected and 540 were a Kilifi-susceptible strain. Mortality after exposure to new PBO-LLINs was only 68% in the wild-collected mosquitoes and as low as 34% when mosquitoes were exposed to used, 24-month old PBO-LLINs.\n                    <jats:italic>Anopheles arabiensis<\/jats:italic>\n                    was the main vector species that survived exposure. Susceptibility tests confirmed very low mortality after exposure to permethrin with or without PBO. Reduced sensitivity can be attributed partly to the aging of the net but also to very high levels of resistance in the local vector population.\n                  <\/jats:p>","DOI":"10.4269\/ajtmh.25-0342","type":"journal-article","created":{"date-parts":[[2026,4,28]],"date-time":"2026-04-28T17:36:25Z","timestamp":1777397785000},"page":"1135-1139","source":"Crossref","is-referenced-by-count":0,"title":["Reduced Efficacy of Piperonyl Butoxide Based Long-Lasting Insecticide-Treated Nets Against Malaria Vectors in Western Kenya"],"prefix":"10.4269","volume":"114","author":[{"given":"Samuel","family":"Kahindi","sequence":"first","affiliation":[{"name":"School of Pure and Applied Sciences, Pwani University, Kilifi, Kenya;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lucy","family":"Abel","sequence":"additional","affiliation":[{"name":"Academic Model Providing Access to Health Care (AMPATH), Eldoret, Kenya;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Erastus","family":"Kirwa","sequence":"additional","affiliation":[{"name":"Academic Model Providing Access to Health Care (AMPATH), Eldoret, Kenya;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mark","family":"Amunga","sequence":"additional","affiliation":[{"name":"Academic Model Providing Access to Health Care (AMPATH), Eldoret, Kenya;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Emma","family":"Kimachas","sequence":"additional","affiliation":[{"name":"Academic Model Providing Access to Health Care (AMPATH), Eldoret, Kenya;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Evans","family":"Omondi","sequence":"additional","affiliation":[{"name":"Academic Model Providing Access to Health Care (AMPATH), Eldoret, Kenya;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Millicent","family":"Cherono","sequence":"additional","affiliation":[{"name":"Academic Model Providing Access to Health Care (AMPATH), Eldoret, Kenya;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Judith","family":"Mangeni","sequence":"additional","affiliation":[{"name":"School of Public Health, College of Health Sciences, Moi University, Eldoret, Kenya;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Andrew","family":"Obala","sequence":"additional","affiliation":[{"name":"School of Medicine, College of Health Sciences, Moi University, Eldoret, Kenya;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christine","family":"Markwalter","sequence":"additional","affiliation":[{"name":"Duke Global Health Institute, Duke University, Durham, North Carolina, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wendy Prudhomme","family":"O\u2019Meara","sequence":"additional","affiliation":[{"name":"School of Public Health, College of Health Sciences, Moi University, Eldoret, Kenya;"},{"name":"Duke Global Health Institute, Duke University, Durham, North Carolina, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"2795","reference":[{"issue":"1","key":"b1","series-title":"Sci Rep","first-page":"10055","article-title":"Pyrethroid-treated bed nets impair blood feeding performance in insecticide resistant mosquitoes","volume":"13","author":"Barreaux","year":"2023"},{"issue":"4","key":"b2","series-title":"Med Vet Entomol","first-page":"465","article-title":"Experimental hut trials of bednets impregnated with synthetic pyrethroid or organophosphate insecticide for mosquito control in The Gambia","volume":"5","author":"Miller","year":"1991"},{"issue":"1","key":"b3","series-title":"Malar J","first-page":"31","article-title":"A cohort study of the effectiveness of insecticide-treated bed nets to prevent malaria in an area of moderate pyrethroid resistance, Malawi","volume":"14","author":"Lindblade","year":"2015"},{"issue":"9","key":"b4","series-title":"Lancet Glob Health","first-page":"e1325","article-title":"Threats to the effectiveness of insecticide-treated bednets for malaria control: Thinking beyond insecticide resistance","volume":"9","author":"Lindsay","year":"2021"},{"issue":"2","key":"b5","series-title":"Emerg Infect Dis","first-page":"199","article-title":"Reduced efficacy of insecticide-treated nets and indoor residual spraying for malaria control in pyrethroid resistance area, Benin","volume":"13","author":"N\u2019Guessan","year":"2007"},{"issue":"10331","key":"b6","series-title":"Lancet","first-page":"1202","article-title":"A new generation of long-lasting insecticidal nets","volume":"399","author":"Kariuki","year":"2022"},{"issue":"8","key":"b7","series-title":"Lancet Planet Health","first-page":"e673","article-title":"Effects of next-generation, dual-active-ingredient, long-lasting insecticidal net deployment on insecticide resistance in malaria vectors in Tanzania: An analysis of a 3-year, cluster-randomised controlled trial","volume":"7","author":"Messenger","year":"2023"},{"issue":"1","key":"b8","series-title":"Malar J","first-page":"77","article-title":"WHO cone bio-assays of classical and new-generation long-lasting insecticidal nets call for innovative insecticides targeting the knock-down resistance mechanism in Benin","volume":"16","author":"Allossogbe","year":"2017"},{"issue":"1","key":"b9","series-title":"Malar J","first-page":"294","article-title":"Effectiveness of piperonyl butoxide and pyrethroid-treated long-lasting insecticidal nets (LLINs) versus pyrethroid-only LLINs with and without indoor residual spray against malaria infection: Third year results of a cluster, randomised controlled, two-by-two factorial design trial in Tanzania","volume":"22","author":"Protopopoff","year":"2023"},{"issue":"1","key":"b10","series-title":"Infect Dis Poverty","first-page":"135","article-title":"Bioefficacy and durability of Olyset\u00ae Plus, a permethrin and piperonyl butoxide-treated insecticidal net in a 3-year long trial in Kenya","volume":"10","author":"Gichuki","year":"2021"},{"issue":"1","key":"b11","series-title":"Parasit Vectors","first-page":"150","article-title":"Personal protection with PBO-pyrethroid synergist-treated nets after 2 years of household use against pyrethroid-resistant Anopheles in Tanzania","volume":"14","author":"Martin","year":"2021"},{"issue":"2","key":"b12","series-title":"PLoS Glob Public Health","first-page":"e0003558","article-title":"LLIN Evaluation in Uganda Project (LLINEUP2) \u2013 Effect of long-lasting insecticidal nets (LLINs) treated with pyrethroid plus pyriproxyfen vs LLINs treated with pyrethroid plus piperonyl butoxide in Uganda: A cluster-randomised trial","volume":"5","author":"Gonahasa","year":"2025"},{"key":"b13","series-title":"Parasite Epidemiol Control","first-page":"e00373","article-title":"Durability of PBO nets (Olyset Plus\u00ae), 12 months after their distribution in Bertoua, Cameroon","volume":"26","author":"Nkahe","year":"2024"},{"issue":"1","key":"b14","series-title":"Parasit Vectors","first-page":"464","article-title":"Relationship between malaria vector survival, infectivity, and insecticide-treated net use in western Kenya","volume":"17","author":"Abel","year":"2024"},{"issue":"1","key":"b15","series-title":"Nat Commun","first-page":"909","article-title":"Genotyping cognate Plasmodium falciparum in humans and mosquitoes to estimate onward transmission of asymptomatic infections","volume":"12","author":"Sumner","year":"2021"},{"issue":"1","key":"b16","series-title":"Parasit Vectors","first-page":"293","article-title":"Effects of larval exposure to sublethal doses of ivermectin on adult fitness and susceptibility to ivermectin in Anopheles gambiae s.s","volume":"16","author":"Kiuru","year":"2023"},{"key":"b17","article-title":"Guidelines for Laboratory and Field-Testing of Long-Lasting Insecticidal Nets.","year":"2013"},{"key":"b18","article-title":"Manual for Monitoring Insecticide Resistance in Mosquito Vectors and Selecting Appropriate Interventions."},{"issue":"1","key":"b19","series-title":"Malar J","first-page":"70","article-title":"Key to the females of Afrotropical Anopheles mosquitoes (Diptera: Culicidae)","volume":"19","author":"Coetzee","year":"2020"},{"key":"b20","series-title":"Malar J","first-page":"125","article-title":"IMP PCR primers detect single nucleotide polymorphisms for Anopheles gambiae species identification, Mopti and Savanna rDNA types, and resistance to dieldrin in Anopheles arabiensis.","volume":"5","author":"Wilkins","year":"2006"},{"issue":"5","key":"b21","series-title":"Cochrane Database Syst Rev","first-page":"CD012776","article-title":"Piperonyl butoxide (PBO) combined with pyrethroids in insecticide-treated nets to prevent malaria in Africa","volume":"5","author":"Gleave","year":"2021"},{"issue":"1","key":"b22","series-title":"Malar J","first-page":"77","article-title":"Western Kenyan Anopheles gambiae showing intense permethrin resistance harbour distinct microbiota","volume":"20","author":"Omoke","year":"2021"},{"issue":"11","key":"b23","series-title":"PLoS One","first-page":"e0303921","article-title":"Insecticide resistance and its intensity in urban Anopheles arabiensis in Kisumu City, Western Kenya: Implications for malaria control in urban areas","volume":"19","author":"Machani","year":"2024"},{"key":"b24","series-title":"Front Public Health","first-page":"55","article-title":"Malaria vectors insecticides resistance in different agroecosystems in western Kenya","volume":"6","author":"Wanjala","year":"2018"},{"issue":"1","key":"b25","series-title":"Parasit Vectors","first-page":"335","article-title":"Insecticide resistance status of Anopheles arabiensis in irrigated and non-irrigated areas in western Kenya","volume":"14","author":"Orondo","year":"2021"},{"issue":"1","key":"b1","series-title":"Sci Rep","first-page":"10055","article-title":"Pyrethroid-treated bed nets impair blood feeding performance in insecticide resistant mosquitoes","volume":"13","author":"Barreaux","year":"2023"},{"issue":"4","key":"b2","series-title":"Med Vet Entomol","first-page":"465","article-title":"Experimental hut trials of bednets impregnated with synthetic pyrethroid or organophosphate insecticide for mosquito control in The Gambia","volume":"5","author":"Miller","year":"1991"},{"issue":"1","key":"b3","series-title":"Malar J","first-page":"31","article-title":"A cohort study of the effectiveness of insecticide-treated bed nets to prevent malaria in an area of moderate pyrethroid resistance, Malawi","volume":"14","author":"Lindblade","year":"2015"},{"issue":"9","key":"b4","series-title":"Lancet Glob Health","first-page":"e1325","article-title":"Threats to the effectiveness of insecticide-treated bednets for malaria control: Thinking beyond insecticide resistance","volume":"9","author":"Lindsay","year":"2021"},{"issue":"2","key":"b5","series-title":"Emerg Infect Dis","first-page":"199","article-title":"Reduced efficacy of insecticide-treated nets and indoor residual spraying for malaria control in pyrethroid resistance area, Benin","volume":"13","author":"N\u2019Guessan","year":"2007"},{"issue":"10331","key":"b6","series-title":"Lancet","first-page":"1202","article-title":"A new generation of long-lasting insecticidal nets","volume":"399","author":"Kariuki","year":"2022"},{"issue":"8","key":"b7","series-title":"Lancet Planet Health","first-page":"e673","article-title":"Effects of next-generation, dual-active-ingredient, long-lasting insecticidal net deployment on insecticide resistance in malaria vectors in Tanzania: An analysis of a 3-year, cluster-randomised controlled trial","volume":"7","author":"Messenger","year":"2023"},{"issue":"1","key":"b8","series-title":"Malar J","first-page":"77","article-title":"WHO cone bio-assays of classical and new-generation long-lasting insecticidal nets call for innovative insecticides targeting the knock-down resistance mechanism in Benin","volume":"16","author":"Allossogbe","year":"2017"},{"issue":"1","key":"b9","series-title":"Malar J","first-page":"294","article-title":"Effectiveness of piperonyl butoxide and pyrethroid-treated long-lasting insecticidal nets (LLINs) versus pyrethroid-only LLINs with and without indoor residual spray against malaria infection: Third year results of a cluster, randomised controlled, two-by-two factorial design trial in Tanzania","volume":"22","author":"Protopopoff","year":"2023"},{"issue":"1","key":"b10","series-title":"Infect Dis Poverty","first-page":"135","article-title":"Bioefficacy and durability of Olyset\u00ae Plus, a permethrin and piperonyl butoxide-treated insecticidal net in a 3-year long trial in Kenya","volume":"10","author":"Gichuki","year":"2021"},{"issue":"1","key":"b11","series-title":"Parasit Vectors","first-page":"150","article-title":"Personal protection with PBO-pyrethroid synergist-treated nets after 2 years of household use against pyrethroid-resistant Anopheles in Tanzania","volume":"14","author":"Martin","year":"2021"},{"issue":"2","key":"b12","series-title":"PLoS Glob Public Health","first-page":"e0003558","article-title":"LLIN Evaluation in Uganda Project (LLINEUP2) \u2013 Effect of long-lasting insecticidal nets (LLINs) treated with pyrethroid plus pyriproxyfen vs LLINs treated with pyrethroid plus piperonyl butoxide in Uganda: A cluster-randomised trial","volume":"5","author":"Gonahasa","year":"2025"},{"key":"b13","series-title":"Parasite Epidemiol Control","first-page":"e00373","article-title":"Durability of PBO nets (Olyset Plus\u00ae), 12 months after their distribution in Bertoua, Cameroon","volume":"26","author":"Nkahe","year":"2024"},{"issue":"1","key":"b14","series-title":"Parasit Vectors","first-page":"464","article-title":"Relationship between malaria vector survival, infectivity, and insecticide-treated net use in western Kenya","volume":"17","author":"Abel","year":"2024"},{"issue":"1","key":"b15","series-title":"Nat Commun","first-page":"909","article-title":"Genotyping cognate Plasmodium falciparum in humans and mosquitoes to estimate onward transmission of asymptomatic infections","volume":"12","author":"Sumner","year":"2021"},{"issue":"1","key":"b16","series-title":"Parasit Vectors","first-page":"293","article-title":"Effects of larval exposure to sublethal doses of ivermectin on adult fitness and susceptibility to ivermectin in Anopheles gambiae s.s","volume":"16","author":"Kiuru","year":"2023"},{"key":"b17","article-title":"Guidelines for Laboratory and Field-Testing of Long-Lasting Insecticidal Nets.","year":"2013"},{"key":"b18","article-title":"Manual for Monitoring Insecticide Resistance in Mosquito Vectors and Selecting Appropriate Interventions."},{"issue":"1","key":"b19","series-title":"Malar J","first-page":"70","article-title":"Key to the females of Afrotropical Anopheles mosquitoes (Diptera: Culicidae)","volume":"19","author":"Coetzee","year":"2020"},{"key":"b20","series-title":"Malar J","first-page":"125","article-title":"IMP PCR primers detect single nucleotide polymorphisms for Anopheles gambiae species identification, Mopti and Savanna rDNA types, and resistance to dieldrin in Anopheles arabiensis.","volume":"5","author":"Wilkins","year":"2006"},{"issue":"5","key":"b21","series-title":"Cochrane Database Syst Rev","first-page":"CD012776","article-title":"Piperonyl butoxide (PBO) combined with pyrethroids in insecticide-treated nets to prevent malaria in Africa","volume":"5","author":"Gleave","year":"2021"},{"issue":"1","key":"b22","series-title":"Malar J","first-page":"77","article-title":"Western Kenyan Anopheles gambiae showing intense permethrin resistance harbour distinct microbiota","volume":"20","author":"Omoke","year":"2021"},{"issue":"11","key":"b23","series-title":"PLoS One","first-page":"e0303921","article-title":"Insecticide resistance and its intensity in urban Anopheles arabiensis in Kisumu City, Western Kenya: Implications for malaria control in urban areas","volume":"19","author":"Machani","year":"2024"},{"key":"b24","series-title":"Front Public Health","first-page":"55","article-title":"Malaria vectors insecticides resistance in different agroecosystems in western Kenya","volume":"6","author":"Wanjala","year":"2018"},{"issue":"1","key":"b25","series-title":"Parasit Vectors","first-page":"335","article-title":"Insecticide resistance status of Anopheles arabiensis in irrigated and non-irrigated areas in western Kenya","volume":"14","author":"Orondo","year":"2021"}],"container-title":["The American Journal of Tropical Medicine and Hygiene"],"original-title":[],"link":[{"URL":"https:\/\/www.ajtmh.org\/view\/journals\/tpmd\/114\/6\/article-p1135.xml","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.ajtmh.org\/downloadpdf\/journals\/tpmd\/114\/6\/article-p1135.xml","content-type":"text\/html","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/www.ajtmh.org\/downloadpdf\/journals\/tpmd\/114\/6\/article-p1135.xml","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,6,3]],"date-time":"2026-06-03T14:16:16Z","timestamp":1780496176000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.ajtmh.org\/view\/journals\/tpmd\/114\/6\/article-p1135.xml"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,6,3]]},"references-count":50,"journal-issue":{"issue":"6"},"URL":"https:\/\/doi.org\/10.4269\/ajtmh.25-0342","relation":{},"ISSN":["0002-9637","1476-1645"],"issn-type":[{"value":"0002-9637","type":"print"},{"value":"1476-1645","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,6,3]]}}}