Cleaning up and spraying the yard is rather difficult. You are welcome to come and spray. Acres involved. Other animals going through the property- elk, deer, bears, and smaller stuff, plus cattle from time to time. Even a mountain lion last winter. My daughter's place, where the fleas have shown up.
Still no heartworm in the region, but probably won't be long.

I will look for vet sold dab on stuff.

And how do you insulate your property? I remember living in Texas where the fleas roamed free, not bothered by fences, barriers against poor immigrant Latinos, and anything else one might think of. Never a last round-up to worry about.