Assessment of Compaction, Temperature, and Duration Factors for Packaging and Transporting of Sterile Male Aedes aegypti (Diptera: Culicidae) under Laboratory Conditions

Abstract

Optimized conditions for the packaging and transportation of sterile males are crucial factors in successful SIT programs against mosquito vector-borne diseases. The factors influencing the quality of sterile males in packages during transportation need to be assessed to develop standard protocols. This study was aimed to investigate the impact of compaction, temperature, and duration factors during packaging and transportation on the quality of gamma-sterilized male Ae. aegypti. Aedes aegypti males were sterilized at a dose of 70 Gy, compacted into Falcon tubes with densities of 40, 80, and 120 males/2 mL; and then exposed to temperatures of 7, 14, 21, and 28 °C. Each temperature setup was held for a duration of 3, 6, 12, 24, and 48 h at a 60 rpm constant vibration to simulate transportation. The parameters of mortality, flight ability, induced sterility, and longevity were investigated. Results showed that increases in density, temperature, and duration significantly increased mortality and reduced flight ability and longevity, but none of the factors significantly affected induced sterility. With a mortality rate of less than 20%, an escaping rate of more than 70%, considerable longevity, and the most negligible effect on induced sterility (approximately 98%), a temperature of 7 °C and a compaction density of 80 males/2 mL were shown to be optimized conditions for short-term transportation (no more than 24 h) with the minimum adverse effects compared with other condition setups.

A self-cooling self-humidifying mosquito carrier backpack for transporting live adult mosquitoes on foot over long distances under challenging field conditions

“…Beyond addressing our project’s specific needs, the backpack described herein may also have other uses. For example, the implementation of the sterile insect technique (SIT) for mosquito control always involve the transportation of live specimens from the production facility to the release points and sometimes beyond the reach of motorized transport (Ernawan et al, 2022; Gómez et al, 2022). Specifically, for SIT procedures, other factors apart from transportation such as packaging and storage conditions may affect the survival and longevity of mosquitoes(Chung et al, 2018; Sasmita et al, 2022), and any potential role for carrier backpacks based on this prototype would probably be limited to parts of remote rural areas or dense urban settlements that may be more readily accessed on foot.…”

Release of sterile Aedes aegypti mosquitoes: chilling effect on mass-reared males survival and escape ability and on irradiated males sexual competitiveness

“…Therefore, and based on our findings, we suggest that sterile males are immobilized at temperatures higher than 4 °C, and to investigate which time–temperature combination will be the least harmful to them. Temperatures between 5 and 10 °C for less than 3 h were recommend 33 , and it was suggested immobilising the males at 7-10 °C for a short period 26 , moreover, Ernawan et al 34 advise to use a temperature of 7 °C for a period that does not exceed 24 h. Within the context of our study, it would be recommended to evaluate the exposure of the mosquitoes to temperatures in the range 4-10 °C for 10–25 min, and to determine the effect on survival, escape ability, and sexual competitiveness under semi-field conditions using standardised protocols, which would allow comparison with other studies. Also, it would be recommended to make improvements in the design of the emergence chamber, so that the first chilling process can be eliminated.…”

From the Lab to the Field: Long-Distance Transport of Sterile Aedes Mosquitoes

“…Transboundary shipments of mosquitoes by air may take more than 24 h [ 8 , 9 ] and recent studies have shown contrasting results for mosquitoes transported as pupae or as chilled or nonchilled sterile males. Furthermore, in these studies, the results were relevant for transportation lasting no more than 24 h [ 9 , 10 , 11 , 12 , 13 , 14 ]. In contrast, operational fruit fly SIT programs entail the long-distance transportation of pupae under different atmospheric conditions (for 67 h to 89 h) without impacting the quality of the flies [ 15 , 16 ].…”