000			04088nam a22004217a 4500
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028			_b Phone: +255 28 298 3384
028			_b Fax: +255 28 298 3386
028			_b Email: vc@bugando.ac.tz
028			_b Website: www.bugando.ac.tz
040			_cdlc
041			_aEnglish
100			_aJoshua Mutagahywa _944203
245			_a The impact of different sprayable surfaces on the effectiveness of indoor residual spraying using a micro encapsulated formulation of lambda-cyhalothrin against Anopheles gambiae s.s.
260			_aMwanza, Tanzania: _bBioMed Central & _b Catholic University of Health and Allied Sciences [CUHAS – Bugando] _c03 April 2015
300			_aPages 1-7
490			_vParasites & vectors Volume 8 Issue 1
520			_aAbstract Background The type of sprayable surface impacts on residual efficacy of insecticide used in indoor residual spraying (IRS). However, there is limited data on common types of wall surfaces sprayed in Zanzibar and mainland Tanzania where IRS began in 2006 and 2007 respectively. The study investigated residual efficacy of micro-encapsulated lambda-cyhalothrin sprayed on common surfaces of human dwellings and domestic animal shelters in Zanzibar and mainland Tanzania. Methods An experimental hut was constructed with different types of materials simulating common sprayable surfaces in Zanzibar and mainland Tanzania. Surfaces included cement plastered wall, mud-daub, white-wash, wood, palm-thatch, galvanized iron-sheets, burnt-bricks, limestone and oil-paint. The World Health Organization (WHO) procedure for IRS was used to spray lambda-cyhalothrin on surfaces at the dose of 20–25 mg/m2. Residual efficacy of insecticide was monitored through cone bioassay using laboratory-reared mosquitoes; Kisumu strain (R–70) of Anopheles gambiae ss. Cone bioassay was done every fortnight for a period of 152 days. The WHO Pesticide Evaluation Scheme (WHOPES) threshold (80% mortality) was used as cut-off point for acceptable residual efficacy. Results A total of 5,800 mosquitoes were subjected to contact cone bioassay to test residual efficacy of lambda-cyhalothrin. There was a statistically significant variation in residual efficacy between the different types of wall surfaces (r = 0.24; p < 0.001). Residual efficacy decreased with increasing pH of the substrate (r = −0.5; p < 0.001). Based on WHOPES standards, shorter residual efficacy (42-56 days) was found in wall substrates made of cement, limestone, mud-daub, oil paint and white wash. Burnt bricks retained the residual efficacy up to 134 days while galvanized iron sheets, palm thatch and wood retained the recommended residual efficacy beyond 152 days. Conclusion The study revealed a wide variation in residual efficacy of micro encapsulated formulation of lambda-cyhalothrin across the different types of wall surfaces studied. In areas where malaria transmission is bimodal and wall surfaces with short residual efficacy comprise > 20% of sprayable structures, two rounds of IRS using lambda-cyhalothrin should be considered. Further studies are required to investigate the impact of sprayable surfaces on residual efficacy of other insecticides commonly used for IRS in Zanzibar and mainland Tanzania.
700			_aJasper N Ijumba _944204
700			_a Harish B Pratap _944205
700			_a Fabrizio Molteni _944206
700			_a Frances E Mugarula _944207
700			_aStephen M Magesa _944208
700			_aMahdi M Ramsan _944209
700			_aJessica M Kafuko _944210
700			_a Elias C Nyanza _919632
700			_aOsia Mwaipape _944211
700			_aJuma G Rutta _944212
700			_a Charles D Mwalimu _944213
700			_aIsaiah Ndong _944214
700			_a Richard Reithinger _944215
700			_a Narjis G Thawer _944216
700			_a Jeremiah M Ngondi _944217
856			_uhttps://doi.org/10.1186/s13071-015-0795-4 _yhttps://doi.org/10.1186/s13071-015-0795-4
942			_2ddc _cVM
999			_c19047 _d19047