I had a huge scare with Calvin & heartworm. He tested positive but in the end was negative. They can only be transmitted thru mosquito bites. Calvin's case was HIGHLY unsual (only the second case in 30 years of my vets career) because he is indoor only. Both Calvin & Hobbes are on a monthly worm pill now. Vet said that the FDA has been trying to get ALL pet owners to administer worm pills just in case. The worming pill takes care of all types of worms...some which are transmittable to humans.
Claudia