A standalone incompatible insect technique enables mosquito suppression in the urban subtropics

Abstract

The strong suppression of Aedes albopictus on two Guangzhou islands in China has been successfully achieved by releasing males with an artificial triple-Wolbachia infection. However, it requires the use of radiation to sterilize residual females to prevent population replacement. To develop a highly effective tool for dengue control, we tested a standalone incompatible insect technique (IIT) to control A. albopictus in the urban area of Changsha, an inland city where dengue recently emerged. Male mosquitoes were produced in a mass rearing facility in Guangzhou and transported over 670 km under low temperature to the release site. After a once-per-week release with high numbers of males (phase I) and a subsequent twice-per-week release with low numbers of males (phase II), the average numbers of hatched eggs and female adults collected weekly per trap were reduced by 97% and 85%, respectively. The population suppression caused a 94% decrease in mosquito biting at the release site compared to the control site. Remarkably, this strong suppression was achieved using only 28% of the number of males released in a previous trial. Despite the lack of irradiation to sterilize residual females, no triple-infected mosquitoes were detected in the field post release based on the monitoring of adult and larval A. albopictus populations for two years, indicating that population replacement was prevented. Our results support the feasibility of implementing a standalone IIT for dengue control in urban areas.

Combining transinfected Wolbachia and a genetic sexing strain to control Aedes albopictus in laboratory-controlled conditions

“…It has been recently shown that IIT alone using triply infected mosquitoes and an automatic mosquito pupae sex sorter for sexing (with an average of 0.13% female contamination rate) allows controlling Ae . albopictus with an 85% population reduction while no population replacement was detected [19]. Genetic sexing has been proposed as a relevant alternative to mechanic sorting as it allows separating males and females at an early development stage, thus significantly reducing production costs.…”

“…aegypti populations in the USA [16], northern Australia [17], Singapore [18] and recently in China for the suppression (strong reduction) of Ae . albopictus populations [19]. One of the issues attributed to IIT is the need for an efficient sex separation method in order to avoid population replacement due to the release of fertile females [6].…”

“…One of the issues attributed to IIT is the need for an efficient sex separation method in order to avoid population replacement due to the release of fertile females [6]. Most large-scale IIT trials have been using either mechanical separation and/or artificial intelligence for sex separation [16,17,19,20]. Genetic sexing has been proposed as a promising alternative to separate males and females at an early development stage, thus significantly reducing production costs [21].…”

Efficiency assessment of a novel automatic mosquito pupae sex separation system in support of area-wide male-based release strategies

“…Automatic mosquito sex sorting systems that can handle a large number of mosquitoes with minimal human intervention and achieve high accuracy hold immense potential to facilitate the efficient production and release of male mosquitoes on a large scale, offering a practical solution to enhance vector control efforts. The company WOLBAKI has capitalized on recent technological advancements and has successfully created an automated mosquito sex sorter (Model: WBK-P0001-V2) based on the manual Fay-Morlan sorter 24 , 25 . The WOLBAKI sex sorter has been fully evaluated in the laboratory on three mosquito species ( Ae.…”

“…albopictus and Culex quinquefasciatus ) 25 and successfully tested in a field trial to suppress Ae. albopictus in an IIT program in China 24 . As part of ongoing efforts to overcome the challenge and improve the efficacy of sex separation, ORINNO Technology Pte Ltd., in collaboration with the National Environment Agency’s (NEA) Environmental Health Institute, Singapore, has designed and developed another automatic mosquito pupae sex separation system (Model No.…”