Repellent and insecticidal efficacy of a new combination of fipronil and permethrin against three mosquito species (Aedes albopictus, Aedes aegypti and Culex pipiens) on dogs

Abstract

BackgroundThree laboratory studies were conducted to assess the repellent and insecticidal efficacy of a combination of fipronil and permethrin (Frontline Tri- Act®/Frontect®) against three mosquito species (Aedes albopictus, Aedes aegypti and Culex pipiens) on dogs.MethodsIn each study, 16 healthy adult dogs were allocated to two groups. Eight dogs were treated with the new topical spot-on combination of fipronil and permethrin on Day 0 and the other eight dogs served as untreated controls. Each dog was exposed to mosquitoes on Days 1, 7, 14, 21 and 28 (and also on Day 35 in the A. aegypti study). After a 1-h exposure period, all mosquitoes were counted and categorized as live or dead and fed or non-fed. Live mosquitoes were kept in an insectary and observed for mortality counts 4, 24 and 48 h post-exposure (PE) for Aedes spp. and 24 and 48 h PE for C. pipiens. Repellency and insecticidal efficacies were defined as the percent reduction in the number of fed and live mosquitoes, respectively, in the treated group as compared to the untreated control group.ResultsRepellency against A. albopictus was ≥93.4% through Day 21 and 86.9% on Day 28. It was ≥91.0% through Day 35 against A. aegypti and ≥90.4% through Day 28 against C. pipiens. Insecticidal efficacy against A. albopictus was ≥97.1% at 24 h PE from Day 7 to Day 28. It was ≥98.0% for the first 3 weeks and still 75.7% on Day 35 against A. aegypti at 24 h PE. For C. pipiens, insecticidal efficacy ranged from 93.8% (Day 7) to 30.9% (Day 28) at 48 h PE.ConclusionsA single topical administration of the combination of fipronil and permethrin provides repellency against mosquitoes on dogs for at least 4 weeks. The product may therefore significantly reduce the potential for the transmission of vector-borne pathogens through the inhibition of mosquito feeding, as well as the discomfort associated with mosquito bites. Moreover, mosquito mortality was induced by contact with the treated dogs, which could aid in the control of mosquitoes, and hence the control of mosquito-borne diseases, in the local vicinity of treated dogs.

Anti‐feeding and insecticidal efficacy of a topical administration of dinotefuran–pyriproxyfen–permethrin spot‐on (Vectra® 3D) on mice against Stegomyia albopicta (= Aedes albopictus)

“…In the current study, the feeding rate of S. albopicta on control mice ranged between 41.4 and 52.8% and was slightly higher than that reported in a previous dog study (24.4–50.6%) using the same mosquito species (Fankhauser et al ., ). The high feeding rate showed that the population of S. albopicta in the experiment was robust (the mosquito population did not suffer any abnormality as a result of taking a bloodmeal from mice), which allowed the effect of the anti‐feeding product to be validated.…”

“…() using the same formulation against S. aegypti in dogs. However, repellency was close to that reported for other commercial products containing permethrin tested against S. albopicta in dogs (Fankhauser et al ., ). Permethrin is both an insecticide and a repellent.…”

“…In a recent combination, 6.7% fipronil and 50.4% permethrin continued to have high repellency against S. aegypti (96.1%) and Culex pipiens (Diptera: Culicidae) (90.4%) for 28 days post‐treatment. For S. albopicta , repellency in dogs ranged from 93.4 to 96.6% until day 21 and then decreased slightly to 86.9% on day 28 (Fankhauser et al ., ). The DPP formulation tested in the current study provided a good anti‐feeding effect in mice, ranging from 89.3 to 100% to day 21 and remaining at 87.4% on day 28.…”

“…These levels are lower than those reported by Fankhauser et al . (), who tested fipronil and permethrin against S. albopicta . Their results show efficacy above 97.1% at 24 h post‐exposure for at least 1 month after application of the product (Fankhauser et al ., ).…”

“…(), who tested fipronil and permethrin against S. albopicta . Their results show efficacy above 97.1% at 24 h post‐exposure for at least 1 month after application of the product (Fankhauser et al ., ). This difference in insecticidal efficacy can be explained by the length of contact time between the mosquito and the treated animal.…”