Last spring, we lost a dog to heartworms which led to congestive heart failure. Our other dog was placed on preventative and has been checked every 6 months to make sure she was heartworm negative.
This week, she had her check up and is now testing positive for heartworm even with the preventative.
The vets answer is to give her some pills for a week and then two injections which I understand are extremely painful to the animal.
I want to know first of all is it possible for her to be heartworm positive even after being on preventative for over a year?
Also, what alternatives are there that are less costly and less painful?
