Many people have been disappointed by the lack of efficacy of products in the past. Some products are not very effective for a variety of reasons. Over time flea populations can develop resistance to insecticides. A product that was effective a decade ago, may lose effectiveness if flea resistance develops. The pesticide may not adequately cover the hind quarters of a large animal if the distance is too great. Products that perform poorly for pet owners typically perform poorly in efficacy trials.
Flea collars marketed in the name, Seresto, have performed well in 2012 and 2013 efficacy tests. The collars are at the high end of the price range, but are effective for up to 8 months. These collars contain a mixture of imidacloprid and flumethrin. In an Italian study* these collars were over 99 percent effective against ticks and 100 percent effective against fleas. In a study (funded by the manufacturer)** flea control varied between 97 and 100 percent for cats and 94 and 100 percent for dogs. These collars may be a useful option for pet owners who have flea problems.
*Dantas-Torres et al.: Efficacy of an imidacloprid/ flumethrin collar against fleas, ticks and tick-borne pathogens in dogs. Parasites & Vectors 2013 6:245.
**Stanneck et al.: Evaluation of the long-term efficacy and safety of an imidacloprid 10%/flumethrin 4.5% polymer matrix collar (Seresto®®) in dogs and cats naturally infested with fleas and/or ticks in multicentre clinical field studies in Europe. Parasites & Vectors 2012 5:66.