title: Investigating mosquito net durability for malaria control in Tanzania - attrition, bioefficacy, chemistry, degradation and insecticide resistance (ABCDR): study protocol.
abstract: BACKGROUND
  Long-Lasting Insecticidal Nets (LLINs) are one of the major malaria vector control tools, with most countries adopting free or subsidised universal coverage campaigns of populations at-risk from malaria. It is essential to understand LLIN durability so that public health policy makers can select the most cost effective nets that last for the longest time, and estimate the optimal timing of repeated distribution campaigns. However, there is limited knowledge from few countries of the durability of LLINs under user conditions.
  
  
  METHODS
  This study investigates LLIN durability in eight districts of Tanzania, selected for their demographic, geographic and ecological representativeness of the country as a whole. We use a two-stage approach: First, LLINs from recent national net campaigns will be evaluated retrospectively in 3,420 households. Those households will receive one of three leading LLIN products at random (Olyset®, PermaNet®2.0 or Netprotect®) and will be followed up for three years in a prospective study to compare their performance under user conditions. LLIN durability will be evaluated by measuring Attrition (the rate at which nets are discarded by households), Bioefficacy (the insecticidal efficacy of the nets measured by knock-down and mortality of mosquitoes), Chemical content (g/kg of insecticide available in net fibres) and physical Degradation (size and location of holes). In addition, we will extend the current national mosquito insecticide Resistance monitoring program to additional districts and use these data sets to provide GIS maps for use in health surveillance and decision making by the National Malaria Control Program (NMCP).
  
  
  CONCLUSIONS
  The data will be of importance to policy makers and vector control specialists both in Tanzania and the SSA region to inform best practice for the maintenance of high and cost-effective coverage and to maximise current health gains in malaria control.
authors.forename: Lena M
authors.initials: LM
authors.lastname: Lorenz
authors.affiliation: Norwegian University of Life Sciences, P,O, Box 5003, Ås 1432, Norway. hans.overgaard@nmbu.no.
authors.forename: Hans J
authors.initials: HJ
authors.lastname: Overgaard
authors.forename: Dennis J
authors.initials: DJ
authors.lastname: Massue
authors.forename: Zawadi D
authors.initials: ZD
authors.lastname: Mageni
authors.forename: John
authors.initials: J
authors.lastname: Bradley
authors.forename: Jason D
authors.initials: JD
authors.lastname: Moore
authors.forename: Renata
authors.initials: R
authors.lastname: Mandike
authors.forename: Karen
authors.initials: K
authors.lastname: Kramer
authors.forename: William
authors.initials: W
authors.lastname: Kisinza
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Moore
mesh_terms: D005191:Family Characteristics; D006801:Humans; D007305:Insecticide Resistance; D057148:Insecticide-Treated Bednets / Q000706:statistics & numerical data*; D007306:Insecticides / Q000494:pharmacology; D008288:Malaria / Q000453:epidemiology / Q000517:prevention & control*; D009032:Mosquito Control / Q000379:methods; D010573:Pesticide Residues / Q000494:pharmacology; D011446:Prospective Studies; D012107:Research Design; D013636:Tanzania / Q000453:epidemiology
chemical_list: D007306:Insecticides; D010573:Pesticide Residues