Deltamethrin-shampoo3 (0,07% Deltamethrin w/w) was tested to assess if it was effective in protecting dogs from the bites of Culex pipiens pipiens).
This was a controlled study (respecting the G.C.P. and the recommendations of the Agency for the evaluation of medicinal products) using 12 Beagle dogs, 6 treated with a 0,07% w/w deltamethrin shampoo and 6 untreated control dogs, placed in individual inox cages. The deltamethrin-shampoo was applied at D0 after the first mosquitoes infestation used for the randomisation of the dogs in the 2 groups. To measure mosquito mortality and anti-feeding effects, each dog was periodically sedated and exposed for 1.5 h to 50 laboratory-reared Culex pipiens pipiens females inside a mosquito-proof net (60 cm X 40 cm X50 cm). After exposure, the dogs were removed from the net and returned to their holding cages. Those mosquitoes remaining in the net were fed on honey-water and
To ensure an adequate supply of adult female mosquitoes at each assessment time-point, two series of 6 dogs (3 control and 3 treated), as matched pairs, based on susceptibility to mosquitoes, were used in a phased but identical concurrent programme. The challenges were performed before the treatment and one day, 1, 2, 3 and 4 weeks after treatment.
The anti-feeding effect was determined for each assessment time-point by the following formula:
Anti-feeding effect =
(anti-feeding rate in treated dogs) - (anti-feeding rate in untreated dogs)
1 - (anti-feeling rate in untreated dogs)
The mosquito mortality effect was determined for each assessment time-point by the following formula:
The mosquito mortality effect was determined for each assessment time-point by the following formula:
Mortality effect =
(mortality rate in (treated dogs) - (mortality rate in untreated dogs)
1 - (mortality rate in untreated dogs)
In the control group, the mean number per dog of engorged females was between 12 to 28 throughout the trial.
The anti-feeding effect of the shampoo against mosquitoes was between 98 and 100% during the first week after the treatment then respectively 92%, 84 and 83 % ay weeks 2, 3 and 4.
The mosquito mortality was between 8 to 11% (48h data) during the first week in treated dogs.
It is concluded that, shampoo would protect a dog from the majority of mosquitoes bites and retain a light killing effect for 2 weeks. This is of interest for canine dirofilariasis prevention.
We thank R. Curtis for the support of Intervet International bv, Boxmeer, The Netherlands and C. Cauvet, S. Vermot and M. Larcher.
Reference
1. Scalibor® Shampoo. Intervet International bv.