I've used nematodes, several times. It's been highly effective every
time, except for this year. Nematodes, Sevin dust/spray both inside the
house and outside in the yard, Frontline Plus on the dog and the cat,
and diatomaceous earth on the animals and the carpet and STILL the
animals are riddled with fleas. We humans are getting bites as well. I
suspect the mild winter we had (Alabama) is the culprit.