title: Use of insecticide quantification kits to investigate the quality of spraying and decay rate of bendiocarb on different wall surfaces in Kagera region, Tanzania.
abstract: BACKGROUND
  Bendiocarb was introduced for the first time for Indoor Residual Spraying (IRS) in Tanzania in 2012 as part of the interim national insecticide resistance management plan. This move followed reports of increasingly alarming levels of pyrethroid resistance across the country. This study used the insecticide quantification kit (IQK) to investigate the intra-operational IRS coverage and quality of spraying, and decay rate of bendiocarb on different wall surfaces in Kagera region.
  
  
  METHODS
  To assess intra-operational IRS coverage and quality of spraying, 104 houses were randomly selected out of 161,414 sprayed houses. A total of 509 samples (218 in Muleba and 291 in Karagwe) were obtained by scraping the insecticide samples from wall surfaces. To investigate decay rate, 66 houses (36 in Muleba and 30 in Karagwe) were selected and samples were collected monthly for a period of five months. Laboratory testing of insecticide concentration was done using IQK(TM) [Innovative Vector Control Consortium].
  
  
  RESULTS
  Of the 509 samples, 89.5% met the World Health Organization (WHO) recommended concentration (between 100-400 mg/m(2)) for IRS target dosage. The proportion of samples meeting WHO standards varied between Karagwe (84.3%) and Muleba (96.3%) (p < 0.001). Assessment of quality of spraying at house level revealed that Muleba (84.8%) had a significantly higher proportion of households that met the expected target dosage (100-400 mg/m(2)) compared to Karagwe (68.9%) (p < 0.001). The quality of spraying varied across different wall substrates in both districts. Evaluation of bendiocarb decay showed that the proportion of houses with recommended concentration declined from 96.9%, 93.5% and 76.2% at months one, two, and three post IRS, respectively (p-trend = 0.03). The rate of decay increased in the fourth and fifth month post spraying with only 55.9% and 26.3% houses meeting the WHO recommendations, respectively.
  
  
  CONCLUSIONS
  IQK is an important tool for assessing IRS coverage and quality of spraying. The study found adequate coverage of IRS; however, residual life of bendiocarb was observed to be three months. Results suggest that in order to maintain the recommended concentrations with bendiocarb, a second spray cycle should be carried out after three months.
authors.affiliation: RTI International, Dar es Salaam, Tanzania. narjis.thawer@gmail.com.
authors.forename: Narjis G
authors.initials: NG
authors.lastname: Thawer
authors.affiliation: RTI International, Dar es Salaam, Tanzania. jngondi@rti.org.
authors.forename: Jeremiah M
authors.initials: JM
authors.lastname: Ngondi
authors.affiliation: Sengerema Health Institute, Sengerema, Tanzania. eradiusmugalurafrances@gmail.com.
authors.forename: Frances E
authors.initials: FE
authors.lastname: Mugalura
authors.affiliation: ACDI/VOCA, Morogoro, Tanzania. tz.isaac@gmail.com.
authors.forename: Isaac
authors.initials: I
authors.lastname: Emmanuel
authors.affiliation: National Malaria Control Programme, Dar es Salaam, Tanzania. dismasi@yahoo.com.
authors.forename: Charles D
authors.initials: CD
authors.lastname: Mwalimu
authors.affiliation: Liverpool School of Tropical Medicine, Liverpool, UK. emorou@biology.uoc.gr.|Department of Biology, University of Crete, Heraklion, Greece. emorou@biology.uoc.gr.
authors.forename: Evangelia
authors.initials: E
authors.lastname: Morou
authors.affiliation: Faculty of Crop Science, Pesticide Science Lab, Agricultural University of Athens, 11855, Athens, Greece. vontas@imbb.forth.gr.|Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 73100, Heraklion, Greece. vontas@imbb.forth.gr.
authors.forename: John
authors.initials: J
authors.lastname: Vontas
authors.affiliation: London School of Hygiene and Tropical Medicine, London, UK. Natacha.Protopopoff@lshtm.ac.uk.
authors.forename: Natacha
authors.initials: N
authors.lastname: Protopopoff
authors.affiliation: London School of Hygiene and Tropical Medicine, London, UK. Mark.Rowland@lshtm.ac.uk.
authors.forename: Mark
authors.initials: M
authors.lastname: Rowland
authors.affiliation: RTI International, Dar es Salaam, Tanzania. mmutagahywa@yahoo.com.
authors.forename: Joshua
authors.initials: J
authors.lastname: Mutagahywa
authors.affiliation: RTI International, Dar es Salaam, Tanzania. slalji@nb.rti.org.
authors.forename: Shabbir
authors.initials: S
authors.lastname: Lalji
authors.affiliation: Swiss Tropical and Public Health Institute, Dar es Salaam, Tanzania. fabrizio.molteni@netcell.org.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Molteni
authors.affiliation: RTI International, Dar es Salaam, Tanzania. mmohamed@rti.org.
authors.forename: Mahdi M
authors.initials: MM
authors.lastname: Ramsan
authors.affiliation: RTI International, Dar es Salaam, Tanzania. rwillilo@nb.rti.org.
authors.forename: Ritha
authors.initials: R
authors.lastname: Willilo
authors.affiliation: London School of Hygiene and Tropical Medicine, London, UK. Lauren.Wright@lshtm.ac.uk.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Wright
authors.affiliation: United States Agency for International Development, Abuja, Nigeria. jkafuko@usaid.gov.
authors.forename: Jessica M
authors.initials: JM
authors.lastname: Kafuko
authors.affiliation: RTI international, Research Triangle Park, North Carolina, USA. indong@rti.org.
authors.forename: Isaiah
authors.initials: I
authors.lastname: Ndong
authors.affiliation: RTI international, Washington, DC, USA. reithinger@rti.org.
authors.forename: Richard
authors.initials: R
authors.lastname: Reithinger
authors.affiliation: RTI International, Dar es Salaam, Tanzania. smagesa@rti.org.
authors.forename: Stephen Masingili
authors.initials: SM
authors.lastname: Magesa
mesh_terms: D000818:Animals; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D006798:Housing; D007306:Insecticides / Q000737:chemistry* / Q000494:pharmacology*; D009032:Mosquito Control / Q000379:methods; D048448:Phenylcarbamates / Q000737:chemistry* / Q000494:pharmacology*; D013499:Surface Properties; D013636:Tanzania
chemical_list: D007306:Insecticides; D048448:Phenylcarbamates; C007725:bendiocarb