title: Spatial repellency of transfluthrin-treated hessian strips against laboratory-reared Anopheles arabiensis mosquitoes in a semi-field tunnel cage.
abstract: BACKGROUND
  Vapour phase spatial repellents deter mosquitoes from attacking one or more humans in a protected space. Simulation models indicate that high coverage of spatial repellents can enhance the impact of long - lasting insecticide nets (LLINs) and indoor residual spraying (IRS) where mosquito vectors commonly bite humans outdoors. Here we report a preliminary evaluation of an effective, user-friendly prototype product for delivering spatial repellents to protect against malaria vector mosquitoes.
  
  
  RESULTS
  Protective efficacy of a 4.0 × 0.3 m strip of hessian sacking treated with 10 ml of transfluthrin was evaluated in a 60 m × 2 m × 2.5 m netting tunnel with malaria-free insectary-reared Anopheles arabiensis Patton mosquitoes. Personal protection, in terms of proportional reduction of exposure to bites, was measured by comparing human landing catches of volunteers with treated and untreated strips. A freshly treated hessian strip reduced mosquito attack rate on human volunteers by > 99% and consistently conferred > 90% protective efficacy for a period of 6 months. Over the entire study period, only 22 out of 1400 released mosquitoes bit volunteers using the treated sacking strip while 894 out of 1400 mosquitoes released into cages containing volunteers using an untreated strip fed upon them.
  
  
  CONCLUSIONS
  Locally available natural fibers may be promising absorbent substrates for delivering spatial repellents, such as transfluthrin, to protect against mosquitoes in tropical settings. However, these observations relate to a single prototype specimen of this particular device, therefore, much more detailed, well replicated studies are essential to establish long-term efficacy, effectiveness, practicability and affordability.
authors.affiliation: Ifakara Health Institute, Biomedical and Environmental Thematic Group, Ifakara, PO Box 53, Morogoro, United Republic of Tanzania. sogoma@ihi.or.tz
authors.forename: Sheila B
authors.initials: SB
authors.lastname: Ogoma
authors.forename: Hassan
authors.initials: H
authors.lastname: Ngonyani
authors.forename: Emmanuel T
authors.initials: ET
authors.lastname: Simfukwe
authors.forename: Anthony
authors.initials: A
authors.lastname: Mseka
authors.forename: Jason
authors.initials: J
authors.lastname: Moore
authors.forename: Gerry F
authors.initials: GF
authors.lastname: Killeen
mesh_terms: D000818:Animals; D000852:Anopheles / Q000187:drug effects*; D003521:Cyclopropanes / Q000494:pharmacology*; D004199:Disease Vectors; D005464:Fluorobenzenes / Q000494:pharmacology*; D006805:Human Experimentation; D006801:Humans; D007302:Insect Repellents / Q000494:pharmacology*; D057148:Insecticide-Treated Bednets; D008297:Male
chemical_list: D003521:Cyclopropanes; D005464:Fluorobenzenes; D007302:Insect Repellents; C560613:transfluthrin