Can a dog that's treated still bring home ticks? [help]

Our dog is on flea, tick, and mosquito prevention. We go to the river every weekend and he plays all over the place and in the tall grass. Our friend's dog gets ticks all the time but we have never found one on ours and his coat is very short and thin so it's pretty easy to inspect him for them. We went to the river on Sunday, and my husband went out there again without us or the dog on Wednesday. It's now Friday morning and my husband just found a tick crawling on his chest. It wasn't engorged so it doesn't look like it had fed on him or our dog. He was laying in bed when he found it and our dogs bed is right next to him where our dog was sleeping. The laundry hamper is also close by where my husband's clothes from Wednesday were. I'm trying to figure out if it's more likely that the tick came from my husband's clothes or from the dog so we know if we need to find a better tick prevention for him. We have a baby and I do not want to risk any of us getting Lyme disease or something. Do tick preventions on dogs make ticks just stay off them completely? Or only keep them from biting dogs? via /r/dogs http://ift.tt/2qNrMkG