Is heartworm prevention necessary?

Yes, heartworm prevention is necessary. They've detected heartworm in every state in the U.S. and it is of growing concern because people in states that didn't have it before but now are having it didn't have their pets on prevention. So for example, I live in an area where we do get coyotes—coyotes can transmit it because it's transmitted from mosquitoes, so if a mosquito bites a coyote and then bites your dog, they can get it. So it is represented in all 50 States so, yes, all dogs need to be protected.