Eltamethrin-impregnated PVC dog collars were tested to assess if they were as effective in protecting dogs from the bites of Culex pipiens pipiens as they were against Phlebotomus perniciosus, as shown by Killick-Kendrick et al. (1997).
This was a controlled study using 16 Beagle dogs, 8 treated with a 4% w/w deltamethrin collar and 8 untreated control dogs, placed in individual cages. The deltamethrin-impregnated collars2 were worn continuously by the treated dogs for up to 6 months. 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 checked for blood feeding and mortality at 24 and 48 hours after exposure to the dogs. In order to ensure an adequate supply of adult female mosquitoes at each assessment time-point, two series of eight dogs (4 control and 4 treated), as matched pairs, based on susceptibility to mosquitoes, were used in a phased but identical concurrent programme. The challenges were performed on weeks 1, 2, 4, 9, 13, 16, 20, 25 and 27 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:
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 25 to 35 throughout the trial.
The anti-feeding effect of the collar against mosquitoes was between 98 and 100% during the 27 weeks of the trial. The mosquito mortality was between 63 to 86% (48h data) during the first 16 weeks in collared dogs.
It is concluded that, deltamethrin collar would protect a dog from the majority of mosquitoes bites and retain a killing effect for a complete mosquitos season. This is of interest for canine dirofilariasis prevention.
We thank R. Curtis for the support of Intervet International bv, Boxmeer, The Netherlands and C. Caubet, M. Roques, V. Andreo and M. Larcher.
Reference
1. Scalibor® Protector Band. Intervet International bv.
2. Killick-Kendrick et al (1997), Medical and Veterinary Entomology, 11., 105 - 111