Field Validation of the Gravid Aedes Trap (GAT) for Collection of Aedes aegypti (Diptera: Culicidae)

Current surveillance methods for adult Aedes aegypti (L.) are expensive, require electrical power (e. g., the BG-Sentinel trap, BGS), are labor intensive (aspirators), or require difficult to use and costly adhesives (sticky ovitraps). Field trials were conducted in Cairns (Australia) to compare the efficacy of the newly designed Gravid Aedes Trap (GAT) against existing sticky ovitraps (MosquiTRAP and double sticky ovitrap) and the BGS. Latin square design trials confirmed that a large GAT using a 9.2-liters bucket treated with Mortein Barrier Outdoor Surface Spray ([ AI] 0.3 g/ kg imiprothrin and 0.6 g/ kg deltamethrin) outperformed a smaller 1.2-liters GAT and collected, on average, 3.7 X and 2.4 X more female Ae. aegypti than the MosquiTRAP and double sticky ovitrap, respectively. Field trials showed that the GAT collected 10-50% less female Ae. aegypti than the BGS trap but 30% more gravid mosquitoes than the BGS. Trials using the BGS and the GAT indicated that there was no difference in capture rates between female Ae. aegypti uninfected and infected with the wMel strain of Wolbachia, and wMel infection rates were nearly identical at > 90% to field captured Ae. aegypti. The potential for the GAT to be used for dengue virus surveillance was also demonstrated with dengue virus type 3RNAdetected in five-sixths and six-sixths pools of Ae. aegypti stored in a GAT held at 28 degrees C and 60% relative humidity for 7 and 14 d, respectively. Mosquito knock down in GATs treated with Mortein surface spray set in 30, 70, and 99% shade was comparable for up to 2 mo, with only similar to 10% of adults escaping. The GAT is therefore a useful tool for capturing adult Ae. aegypti and may be suitable for other container-inhabiting species such as Aedes albopictus (Skuse) and Culex quinquefasciatus Say. The low cost and practicality of operation make the GAT suitable for vector surveillance and projects requiring monitoring of mosquitoes for Wolbachia and arboviruses, especially in developing countries.