A combination of 10% (w/v) of imidacloprid and 50% (w/v) of permethrin as spot-on form is effective in inhibiting blood feeding by adult female mosquitoes, Japanese researchers report.

Furthermore, the team led by Tsugihiko Kamio, of the National Institute of Animal Health, Tsukuba, found that the efficacy lasts under outdoor conditions for 42 days after treatment.

“After treatment, dogs in the control and treated groups were kept separately from the evening (17:00) to the morning of the following day (09:00) in two different kennels installed outdoors to mimic realistic dog-raising conditions,” Kamio’s team explains.

The investigators collected mosquitoes in the kennels by light traps placed in the kennels and a sweep net to determine evidence of blood feeding, and for species identification.

Precisely, mosquitoes were collected on days 5, 3 and 1 before agent treatment and the day of treatment, as well as on days 3, 7, 14, 21, 28, 35 and 42 after treatment.

The results, published online on March 14th in Veterinary Parasitology, showed that percentages of blood-fed mosquitoes measured at days 0, 3, 21, 28 and 42 after treatment were statistically significantly lower (p < 0.01) in the treated group than in the control group.

Moreover, the authors observed that “the most commonly collected mosquito, Culex tritaeniorhynchus, revealed statistically significant lower percentages (p < 0.01) of blood-fed mosquitoes in the treated group than in the control group at the day of treatment and days 3, 7, 21, 28 and 42 after treatment”.

References

• Vet Parasitol, available online 14 March 2008. doi:10.1016/j.vetpar.2008.03.004