RT Journal Article SR Electronic T1 Efficacy of Aedes aegypti control by indoor Ultra Low Volume (ULV) insecticide spraying in Iquitos, Peru JF bioRxiv FD Cold Spring Harbor Laboratory SP 231134 DO 10.1101/231134 A1 Christian Gunning A1 Kenichi Okamoto A1 Helvio Astete A1 Gissella M. Vasquez A1 Erik Erhardt A1 Clara Del Aguila A1 Raul Pinedo A1 Roldan Cardenas A1 Carlos Pacheco A1 Enrique Chalco A1 Hugo Rodriguez-Ferruci A1 Thomas W. Scott A1 Alun L. Lloyd A1 Fred Gould A1 Amy C. Morrison YR 2017 UL http://biorxiv.org/content/early/2017/12/08/231134.abstract AB Background Aedes aegypti is a primary vector of dengue, chikungunya, Zika, and urban yellow fever viruses. Indoor, ultra low volume (ULV) space spraying with pyrethroid insecticides is the main approach used for Ae. aegypti emergency control in many countries. Given the widespread use of this method, the lack of large-scale experiments or detailed evaluations of municipal spray programs is problematic.Methodology/Principal Findings Two experimental evaluations of non-residual, indoor ULV pyrethroid spraying were conducted in Iquitos, Peru. In each, a central sprayed sector was surrounded by an unsprayed buffer sector. In 2013, spray and buffer sectors included 398 and 765 houses, respectively. Spraying reduced the mean number of adults captured per house by ~83 percent relative to the pre-spray baseline survey. In the 2014 experiment, sprayed and buffer sectors included 1,117 and 1,049 houses, respectively. Here, the sprayed sector’s number of adults per house was reduced ~64 percent relative to baseline. Parity surveys in the sprayed sector during the 2014 spray period indicated an increase in the proportion of very young females. We also evaluated impacts of a 2014 citywide spray program by the local Ministry of Health, which reduced adult populations by ~60 percent. In all cases, adult densities returned to near-baseline levels within one month.Conclusions/Significance Our results demonstrate that densities of adult Ae. aegypti can be reduced by experimental and municipal spraying programs. The finding that adult densities return to approximately pre-spray densities in less than a month is similar to results from previous, smaller scale experiments. Our results demonstrate that ULV spraying is best viewed as having a short-term entomological effect. The epidemiological impact of ULV spraying will need evaluation in future trials that measure capacity of insecticide spraying to reduce disease transmission.