Our customer asked:
My wife has been using frontline once every 3-4 weeks for months and only did the cats two weeks ago and the fleas are now on the cats again. Before that it only lasted for 3 weeks. It has worked in the past but seems to be not working. We've been treating the house as well with spray and regularly hoover. Is there another flea treatment you could recommend as in the past the above treatments have worked but don't seem to any longer. The fleas target our young daughter and she's covered in bites.
A lot of people have been saying the same thing about Frontline this year. It has been a particularly bad year for fleas anyway, the wet summer suited them perfectly and the background populations built up to a huge level. Even if the Frontline was working well now, it might be that you would soon see fleas again, even if they die off after a day or two and are replaced by other fleas.
I am unsure if Frontline is genuinely becoming less effective than it used to be. This maybe the case, or it might be that there are just so many fleas around this year. We cannot really tell. As a precaution it would be a sensible idea to switch to a different product, at least until the flea population has died down. The product I would recommend is Advantage. It has a completely different active ingredient, but is also a spot-on which you can buy without a vet's prescription. I would have to recommend that you vacuum clean your carpets regularly, and spray around with a household insecticide again if you have not done that for a while. Acclaim would be a good choice for household flea treatment.