I had to look up Effectix to see what was in it -- it turns out it's just Virbac's version of fipronil (same stuff that's in Frontline, Pet Armor, etc.)
Fipronil is an older generation of flea treatment. Many consumers have been reporting it doesn't work any more. We've seen it completely fail in my area, so our rescue stopped using all Fipronil products. When I asked shelter vets why they stopped using it too, their experience was the same -- one vet told me she believes the local flea population is resistant to to it. Some manufacturers of fipronil dispute resistance being a real phenomenon, but you know what you experienced.
I would get one of the newer generation of RX anti-flea products from the vet, if you have an active flea infestation: NexGuard, Activyl, Vectra 3D, and even Comfortis all seem to work very well. Bravecto is another one, but it seems to cause GI issues in some dogs. Comfortis also sometimes has side effects (in how it interacts with some HW meds). I've personally used NexGuard and been impressed. One shelter I know use Activyl, and the dogs I pull for rescue from them never have fleas. A friend uses Vectra with good results.
You need a presecription for any of these newer generation of pills or topicals, and they all are fairly pricey -- around $20/month. You should be able to buy them from the vet (or from 800petmeds or Dr. Fosters & Smith if your vet will fax them the prescription).
FWIW, I'm still having very good luck with Advantage II (an OTC product), and Advantage Multi (RX only), but not everyone is -- it's newer than Fipronil but has been out long enough for resistance to be possible in some areas.
You also need to treat your yard ASAP. You can get spray at Home Depot or Lowes that attaches to the garden hose, or use a natural alternative. If you go the natural route, Wondercide's yard spray is excellent (www.wondercide.com
) but you have to re-spray weekly for at least a month (it's cedar oil and smells great -- it also drives away mosquitoes on the days you spray). Whatever you use, it's imperative to knock down the flea population outside so that the dog doesn't keep bringing them in.
My dad had good luck with the Seresto collar, but he had no flea infestation -- it just kept them away. I haven't talked with anyone in my circle who used it to treat
an active infestation, as opposed to preventing one from happening, so I don't have good info on effectiveness.
One other thought: if there are young kids in the picture here, I think I'd ask the vet for a pill or chew (NexGuard, Bravecto, Comfortis...), not a topical or collar. That way you don't have to worry about kids snuggling on the dog after you put the topical med on or rubbing on a flea collar.