Effect of Dinotefuran, Permethrin, and Pyriproxyfen (Vectra(®) 3D) on the Foraging and Blood-Feeding Behaviors of Aedes albopictus Using Laboratory Rodent Model

SIMPLE SUMMARY: Tiger mosquito (Aedes albopictus) is a harmful vector involved in the transmission of several diseases to humans and their pets. Currently, several veterinary products are used to prevent pets against bites of arthropod vectors. However, there is no available information on the effect of these products on feeding and host choice behaviors of Aedes albopictus in the presence of treated and untreated hosts, as is the case of treated dogs present in close physical contact with their owners. The present study investigated the effect of a spot-on product (Vectra(®) 3D) on the feeding and host choice behaviours of Aedes albopictus when treated and untreated hosts are presents. Laboratory rodent model was performed to simulate the natural conditions. Rat and mouse hosts were alternately treated with Vectra(®) 3D and exposed simultaneously to starved mosquitoes. Results showed that Vectra(®) 3D-treated hosts are perfectly protected against up to 82% of mosquitoes. While up to 21% of mosquitoes were repelled from untreated hosts when these latter are present in close physical contact (30 cm) with treated ones suggesting an indirect protection that can allowed the protection of owners who treat their pets with Vectra(®) 3D. ABSTRACT: Dinotefuran-Permethrin-Pyriproxyfen (DPP) is used to kill and repel mosquitoes from dogs. However, the influence of the product on the host-seeking behavior of mosquitoes remains unknown. The interference of DPP with the host selection of unfed female Aedes albopictus was investigated. A total of 18 animals (9 mice and 9 rats) were divided into three groups of six animals each. DU: DPP treated rats (n = 3) with untreated mice (n = 3), UD: DPP treated mice (n = 3) with untreated rats (n = 3) and control UU: untreated mice (n = 3) and untreated rats (n = 3). In each group, the rats and mice were placed 30 cm apart. After sedation, the animals in each group were exposed twice (Day 1 and Day 7 post-treatment) for one hour to 71 ± 3 female mosquitoes. Mosquitoes were categorized after the 2-h post-exposure period as dead or alive. Blood-meal origin was determined from mosquitoes using a newly customized duplex qPCR. The highest values of forage ratio (1.36 ≥ wi ≤ 1.88) and selection index (0.63 ≥ Bi ≤ 0.94) for rat hosts indicates a preference of mosquitoes for this species as compared to mice when co-housed during the exposure. The mosquitoes only seldom fed on mice, even in the untreated group. The anti-feeding effect of DPP was therefore only assessed on rat’s hosts. The results showed that DPP, when directly applied on rats, provided a direct protection of 82% and 61% on Day 1 and Day 7, respectively, while when applied on mice hosts (UD), the DPP provided an indirect protection of 21% and 10% on Day 1 and Day 7, respectively. The results showed also that DPP, when applied on rats, provided a direct protection against Ae. albopictus bites. This effect did not result in increased exposure of the untreated host placed in the same cage at a distance of 30 cm.