Metofluthrin: investigations into the use of a volatile spatial pyrethroid in a global spread of dengue,chikungunya and Zika viruses

Background: metofluthrin reduces biting activity in aedes aegypti through the confusion,knockdown,and subsequent kill of a mosquito. a geographical spread in dengue,chikungunya,and zika viruses,increases intervention demands. response to a zika outbreak may require a different strategy than dengue,as high-risk individuals,specifically pregnant women,need to be targeted. methods: in semi-field conditions within a residential property in cairns,queensland,the impacts of metofluthrin on biting behaviour of free-flying wolbachia-infected ae. aegypti were evaluated. results: mortality in ae. aegypti exposed to metofluthrin over a 22 h period was 100% compared to 2.7% in an untreated room. no biting activity was observed in mosquitoes up to 5 m from the emanator after 10 min of metofluthrin exposure. use of metofluthrin reduced biting activity up to 8 m,regardless of the host’s proximity (near or far) to a dark harbourage area (ha) (p < 0.0001 and p = 0.006),respectively. in the presence or absence of the metofluthrin emanator,the host was most likely bitten when located immediately next to a ha (within 1 m) versus 8 m away from the ha (p = 0.006). the addition of a ceiling fan (0.8 m/s airflow) prevented all biting activity after 10 min of metofluthrin exposure. previously unexposed ae. aegypti were less likely to reach the host in a metofluthrin-treated room ( x − $ big(overset{-}{x} $ = 31%) compared to an untreated room ( x − = 100 % $ overset{-}{x}=100% $ ) (p < 0.0001). in a treated room,if the mosquito had not reached the host within 30 s,they never would. upon activation,the time required for metofluthrin to infiltrate protected locations within a room causing knockdown in caged mosquitoes,required more time than exposed locations (p < 0.003); however exposed and protected locations do eventually reach equilibrium,affecting mosquitoes equally throughout the room. conclusion: metofluthrin is effective in interrupting indoor host-seeking in ae. aegypti. metofluthrin’s efficacy is increased by centrally locating the emanator in the room,and by using a fan to increase airflow. newly treated rooms may require a period of 2-4 h for sufficient distribution of the metofluthrin into protected locations where mosquitoes may be resting. © 2017 the author(s).