BackgroundAedes 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 findingsTwo 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/SignificanceOur 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 human infection or disease.
words 44Background 45Aedes aegypti is a primary vector of dengue, chikungunya, Zika, and urban yellow fever viruses. 46Indoor, ultra low volume (ULV) space spraying with pyrethroid insecticides is the main 47 approach used for Ae. aegypti emergency control in many countries. Given the widespread use of 48 this method, the lack of large-scale experiments or detailed evaluations of municipal spray 49 programs is problematic. 50Methodology/Principal Findings 51Two experimental evaluations of non-residual, indoor ULV pyrethroid spraying were conducted 52in Iquitos, Peru. In each, a central sprayed sector was surrounded by an unsprayed buffer sector. 53In 2013, spray and buffer sectors included 398 and 765 houses, respectively. Spraying reduced 54 the mean number of adults captured per house by ~83 percent relative to the pre-spray baseline 55 survey. In the 2014 experiment, sprayed and buffer sectors included 1,117 and 1,049 houses, 56 respectively. Here, the sprayed sector's number of adults per house was reduced ~64 percent 57 relative to baseline. Parity surveys in the sprayed sector during the 2014 spray period indicated 58 an increase in the proportion of very young females. We also evaluated impacts of a 2014 59 citywide spray program by the local Ministry of Health, which reduced adult populations by ~60 60 percent. In all cases, adult densities returned to near-baseline levels within one month. 61 Conclusions/Significance 62 Our results demonstrate that densities of adult Ae. aegypti can be reduced by experimental and 63 municipal spraying programs. The finding that adult densities return to approximately pre-spray 64 densities in less than a month is similar to results from previous, smaller scale experiments. Our 65 results demonstrate that ULV spraying is best viewed as having a short-term entomological 66 effect. The epidemiological impact of ULV spraying will need evaluation in future trials that 67 measure capacity of insecticide spraying to reduce disease transmission. 68 69 70 AUTHOR SUMMARY-196 words 71Aedes aegypti is a primary vector for medically important viruses that typically resides within 72houses. Indoor, ultra low volume (ULV) adulticide space spraying is considered to be more 73 effective in controlling Ae. aegypti populations than outdoor spraying, and is widely used in 74 tropical cities. Given the widespread use of indoor ULV spraying in emergencies by municipal 75 control programs, the lack of large spatial scale evaluations is problematic. We conducted two 76 large-scale experiments to evaluate indoor ULV pyrethroid spraying in the city of Iquitos, Peru 77 in 2013 and 2014, and we also evaluated a municipal spraying effort. Our results demonstrate 78 that densities of adults can be reduced by ULV spraying, but that adult densities in sprayed areas 79return to approximately pre-spray densities in less than a month. These findings agree with 80 results from previous, smaller scale experiments, and confirm that ULV spraying should be 81 viewed as having a short-term impact on Ae. aegypti...
A new species of sand fly, which we describe as Lutzomyia (Trichophoromyia) nautaensis n. sp., was collected in the northern Peruvian Amazon Basin. In this region of Peru, cutaneous leishmaniasis is transmitted primarily by anthropophilic sand flies; however, zoophilic sand flies of the subgenus Trichophoromyia may also be incriminated in disease transmission. Detection of Leishmania spp. in Lutzomyia auraensis Mangabeira captured in the southern Peruvian Amazon indicates the potential of this and other zoophilic sand flies for human disease transmission, particularly in areas undergoing urban development. Herein, we describe Lutzomyia (Trichophoromyia) nautaensis n. sp., and report new records of sand flies in Peru.
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