Use of the CDC autocidal gravid ovitrap to control and prevent outbreaks of Aedes aegypti (Diptera: Culicidae)

Abstract

Populations ofAedes aegypti (L.) can be managed through reductions in adult mosquito survival, number of offspring produced, or both. Direct adult mortality can be caused by the use of space sprays or residual insecticides to mosquito resting sites, and with a variety of residual insecticide-impregnated surfaces that are being tested, such as curtains, covers for water-storage vessels, bednets, and ovitraps. The fertility ofAe. aegypti populations can be reduced by the use of autocidal oviposition cups that prevent the development of mosquitoes inside the trap by mechanical means or larvicides, as well as by releasing sterile, transgenic, and para-transgenic mosquitoes. Survival and fertility can be simultaneously reduced by capturing gravid female Ae. aegypti with sticky gravid traps. We tested the effectiveness of the novel Centers for Disease Control and Prevention autocidal gravid ovitrap (CDC-AGO trap) to control natural populations ofAe. aegypti under field conditions in two isolated urban areas (reference vs. intervention areas) in southern Puerto Rico for 1 yr. There were significant reductions in the captures of female Ae. aegypti (53-70%) in the intervention area The presence of three to four AGO control traps per home in 81% of the houses prevented outbreaks of Ae. aegypti, which would be expected after rains. Mosquito captures in BG-Sentinel and AGO traps were significantly and positively correlated, showing that AGO traps are useful and inexpensive mosquito surveillance devices. The use of AGO traps to manage Ae. aegypti populations is compatible with other control means such as source reduction, larviciding, adulticiding, sterile insect techniques, induced cytoplasmic incompatibility, and dominant lethal gene systems.

Fig. 1

Weekly average temperature (°C) and accumulated rainfall (mm) from October 2011 to October 2012 in Villodas and La Margarita communities in southern Puerto Rico.

Fig. 2

Description of the CDC-AGO (patent pending): (A) Black polypropylene netting to exclude the entry of debris, (B) polyethylene cylinder that serves as the trap entrance and capture chamber, (C) sticky surface made of a black styrene cylinder coated with a nonsetting adhesive, (D) screen barrier to prevent adult mosquitoes from reaching the infusion reservoir, (E) black pail lid, (F) black polyethylene pail, (G) drainage holes, (H) water, and (I) hay packet.

Fig. 3

(A, B) Weekly variation in the numbers of female Ae. aegypti captured in BG-Sentinel (sum of 3-d captures per week) and SAGO (7-d captures) traps, and accumulated rainfall (second and third weeks before sampling) in the reference (Villodas) and intervention (La Margarita) areas. Mosquitoes were monitored in both areas before applying control measures from October to December 2011 and afterwards until October 2012, following the intervention. Rainfall data are plotted with a forward lag time of 2 wk to facilitate visual association with the numbers of mosquitoes.

Fig. 4

Maps showing the location of SAGO traps and changes in overall weekly averages of female Ae. aegypti per trap before (October–December of 2011) and after the intervention (December 2011–October 2012) in the two study areas.

Fig. 5

Maps showing the location of BG-Sentinel traps and changes in overall weekly averages of female Ae. aegypti per trap before (October–December of 2011) and after the intervention (December 2011–October 2012) in the two study areas.

Fig. 6

Deficit of female Ae. aegypti in the intervention area (difference in mosquito density between the reference and intervention areas per week) against the density in the reference area (without control traps), from weeks 20 through 52 to show the reduction in numbers caused by the control traps.

Fig. 7

(A) Plot of average numbers of female Ae. aegypti captured in SAGO and BG-Sentinel traps per day for all the weeks of the study. (B) Comparison of the percentages SAGO and BG-Sentinel traps that were positive for female Ae. aegypti per week during the study.