Category Archives: heartworm

Heartworm Information

If you’ve been keeping up with the news, you’ve probably been hearing a lot about Zika virus, a disease that is transmitted by mosquitoes and can make us ill. But did you know that mosquitoes carry diseases that can cause illness in our pets? Most pet owners are aware of diseases like rabies, feline leukemia, and canine kennel cough. These diseases are transmitted to our pets by contact with other cats, dogs or sometimes wildlife. Heartworm disease is an infection that can be transmitted to our dogs and cats by the bite of an infected mosquito. That means that our pets do not need to be around other animals to become infected with heartworm disease.

Luckily for pet owners, heartworm disease can be very easy to prevent. There is a variety of monthly medications that can be prescribed to your dog and cat, including flavored chewable tablets and topical medications.

Heartworm disease has been on the rise in Pennsylvania over the past few years. According to the American Heartworm Society, vet clinics in PA were reporting an average of 1-5 heartworm cases per year in 2010. Some clinics in northern PA were seeing even less than that. Then in 2013, at the next report, all surveyed clinics were reporting at least 1-5 cases per year, and many clinics reported 6-25 cases per year. This does not include the millions of pets who are never tested.

Heartworm disease affects dogs and cats in different ways. The heartworm larvae is injected into the bloodstream by the mosquito. In dogs, the larvae grow into adult worms in the heart and lung vessels, causing severe damage that may be permanent. There can be as many as 50 adult worms in the heart and lungs in an infected dog. Symptoms in dogs can range from a mild cough to full blown heart failure. Sometimes there are no symptoms at all! In cats, the worm burden tends to be much less but they are more sensitive to the larvae. The larvae can trigger a severe inflammatory reaction in the lungs similar to asthma. This inflammation can cause fatal respiratory disease.

Once infected, heartworm disease can be painful and expensive to treat. There is an injection for dogs that is given multiple times over the course of 1 month to kill the adult heartworms. There is no specific treatment for cats, only supportive care.

It is recommended to test for heartworm disease yearly, even if your dog is on year round prevention. This helps to ensure that the prevention is working. The test also checks for other diseases like Lyme disease. Reliable testing is not available for cats and they can be given heartworm preventive without testing. It is recommended to test your dog before starting the preventive. The preventives only kill the larvae that have been transmitted to your dog within the past 30 days. For example, if your dog was bitten by an infected mosquito on May 15th and you started your preventive on July 1st, your dog is NOT protected from heartworm disease. You should test again in 6-12 months to check for a mature infection. This is another advantage to giving heartworm prevention year round; the risk of missing an infection is much less. And with winters getting warmer, how do we know when the last mosquito left Pennsylvania? September? December? Or did they ever leave at all?

For more information about canine and feline heartworm disease, talk to your vet or visit the American Heartworm Society’s website at www.heartwormsociety.org.

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.