Posted 4/16/2017 1:38 PM (GMT -5)
No matter what treatment you use, the tick must still bite the animal in order to get the treatment.
And yes, they can still transmit diseases. Treating pets lessens the risk considerably for the pet and the people though, and if they drop off the pet, then it's a doomed tick anyway, as the poison will be effective at killing them, but it doesn't happen right away.
Doubling up on preventatives though could pose risks for your dog, just be aware of that too.