title: Experimental hut evaluation of a novel long-lasting non-pyrethroid durable wall lining for control of pyrethroid-resistant Anopheles gambiae and Anopheles funestus in Tanzania.
abstract: A novel, insecticide-treated, durable wall lining (ITWL), which mimics indoor residual spraying (IRS), has been developed to provide prolonged vector control when fixed to the inner walls of houses. PermaNet®ITWL is a polypropylene material containing non-pyrethroids (abamectin and fenpyroximate) which migrate gradually to the surface.
  
  
  
  An experimental hut trial was conducted in an area of pyrethroid-resistant Anopheles gambiae s.l. and Anopheles funestus s.s. to compare the efficacy of non-pyrethroid ITWL, long-lasting insecticidal nets (LLIN) (Interceptor®), pyrethroid ITWL (ZeroVector®), and non-pyrethroid ITWL + LLIN.
  
  
  
  The non-pyrethroid ITWL produced relatively low levels of mortality, between 40-50% for An. funestus and An. gambiae, across all treatments. Against An. funestus, the non-pyrethroid ITWL when used without LLIN produced 47% mortality but this level of mortality was not significantly different to that of the LLIN alone (29%, P = 0.306) or ITWL + LLIN (35%, P = 0.385). Mortality levels for An. gambiae were similar to An. funestus with non-pyrethroid ITWL, producing 43% mortality compared with 26% for the LLIN. Exiting rates from ITWL huts were similar to the control and highest when the LLIN was present. An attempt to restrict mosquito access by covering the eave gap with ITWL (one eave open vs four open) had no effect on numbers entering. The LLIN provided personal protection when added to the ITWL with only 30% blood-fed compared with 69 and 56% (P = 0.001) for ITWL alone. Cone bioassays on ITWL with 30 min exposure after the trial produced mortality of >90% using field An. gambiae.
  
  
  
  Despite high mortality in bioassays, the hut trial produced only limited mortality which was attributed to pyrethroid resistance against the pyrethroid ITWL and low efficacy in the non-pyrethroid ITWL. Hut ceilings were left uncovered and may have served as a potential untreated refuge. By analogy to IRS campaigns, which also do not routinely treat ceilings, high community coverage with ITWL may still reduce malaria transmission. Restriction of eave gaps by 75% proved an inadequate barrier to mosquito entry. The findings represent the first 2 months after installation and do not necessarily predict long-term efficacy.
authors.affiliation: National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania. r_malima@hotmail.com.|Department of Entomology and Parasitology, Kilimanjaro Christian Medical University College (KCMUCo) of Tumaini University, Moshi, Kilimanjaro, Tanzania. r_malima@hotmail.com.
authors.forename: Robert
authors.initials: R
authors.lastname: Malima
authors.affiliation: Department of Entomology and Parasitology, Kilimanjaro Christian Medical University College (KCMUCo) of Tumaini University, Moshi, Kilimanjaro, Tanzania.
authors.forename: Basiliana
authors.initials: B
authors.lastname: Emidi
authors.affiliation: Department of Disease Control, London School of Hygiene and Tropical Medicine (LSHTM), London, UK.
authors.forename: Louisa A
authors.initials: LA
authors.lastname: Messenger
authors.affiliation: Department of Disease Control, London School of Hygiene and Tropical Medicine (LSHTM), London, UK.
authors.forename: Richard M
authors.initials: RM
authors.lastname: Oxborough
authors.affiliation: National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania.
authors.forename: Bernard
authors.initials: B
authors.lastname: Batengana
authors.affiliation: National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania.
authors.forename: Wema
authors.initials: W
authors.lastname: Sudi
authors.affiliation: Department of Disease Control, London School of Hygiene and Tropical Medicine (LSHTM), London, UK.
authors.forename: Sophie
authors.initials: S
authors.lastname: Weston
authors.affiliation: National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania.
authors.forename: George
authors.initials: G
authors.lastname: Mtove
authors.affiliation: National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania.
authors.forename: Joseph P
authors.initials: JP
authors.lastname: Mugasa
authors.affiliation: Department of Entomology and Parasitology, Kilimanjaro Christian Medical University College (KCMUCo) of Tumaini University, Moshi, Kilimanjaro, Tanzania.
authors.forename: Franklin W
authors.initials: FW
authors.lastname: Mosha
authors.affiliation: Department of Disease Control, London School of Hygiene and Tropical Medicine (LSHTM), London, UK.
authors.forename: Mark W
authors.initials: MW
authors.lastname: Rowland
authors.affiliation: National Institute for Medical Research, Amani Research Centre, Muheza, Tanzania.
authors.forename: William
authors.initials: W
authors.lastname: Kisinza
mesh_terms: D000818:Animals; D000852:Anopheles; D001565:Benzoates; D006801:Humans; D007305:Insecticide Resistance; D007306:Insecticides; D007559:Ivermectin / Q000031:analogs & derivatives*; D008288:Malaria / Q000517:prevention & control; D009032:Mosquito Control; D011126:Polypropylenes; D011720:Pyrazoles; D011722:Pyrethrins; D013636:Tanzania
chemical_list: D001565:Benzoates; D007306:Insecticides; D011126:Polypropylenes; D011720:Pyrazoles; D011722:Pyrethrins; C048324:abamectin; D007559:Ivermectin; C415144:fenpyroximate
keywords: Experimental huts; Insecticide-treated wall lining; Long-lasting insecticidal nets; Malaria control; Pyrethroid resistance