Hidden Valley Animal Clinic

100 Oakhurst Drive
McMurray, PA 15317



What Is Heartworm Disease?

Heartworm disease is a serious and potentially fatal condition caused by parasitic worms living in the arteries of the lungs and occasionally in the right side of the heart of dogs, cats and other species of mammals, including wolves, foxes, ferrets, sea lions and (in rare instances) humans. Heartworms are classified as nematodes (roundworms) and are filarids, one of many species of roundworms.
Dogs and cats of any age or breed are susceptible to infection.

What Is Heartworm Disease?


FDA Main Consumer Health Information Page

Frequently Asked Questions

I have missed two months of heartworm prevention for my dog. Should I worry?

answer: Yes, you should worry. You need to consult your veterinarian, and immediately start your dog back on monthly preventive and retest in seven months. The reason for testing seven months later is that heartworms must be approximately seven months old before the infection can be diagnosed.

Is heartworm contagious from dog to dog?

answer: No. Heartworms can be transmitted from animal to animal only by the bite of a mosquito carrying the infective stage of the larvae. Heartworms release live young (microfilaria) directly into the bloodstream of a dog. When a mosquito takes a blood meal from an infected pet, it may become infected by several microfilariae. The larvae then develop into an infective stage within the mosquito. As the mosquito bites another susceptible dog or cat, the infective larvae can be left behind to cause infection. The life cycle of the heartworm requires the mosquito as an "intermediate host." Without the mosquito, heartworms can not be transmitted. 

Is there an effective natural prevention for heartworm?

answer: No, there is no natural prevention for heartworms.