Is Your Pet Ready for Heartworm Season?

Thanks to an extremely harsh winter, we may see a decrease in the mosquito population compared to previous years. Still, we must take precautions against heartworm disease. Mosquitoes are the intermediate host of heartworms and are responsible for spreading this deadly disease. Dogs cannot give the disease to other dogs without the aid of mosquitoes. As pet owners, we need to be responsible for protecting our pet’s health by preventing heartworm disease.

Heartworm disease is caused by Dirofilaria immitus. When this parasite is mature, it resides in an animal’s blood vessels very close to the heart, resulting in heart disease and elevated blood pressure. Currently there is only one FDA approved medication that kills the adult worms in dogs, and nothing is available to kill adult heartworms in cats. This is why preventing adult worms is so important.

How does heartworm prevention work?

There are many preventatives on the market: oral, topical and injectable forms. Most preventatives need to be dosed every 30 days. When an animal receives a monthly dose of prevention, the preventative kills any microfilaria (baby heartworms) that an animal may have been exposed to within the last 30 days. That is why dosing every 30 days is so important. Even though transmission of heartworms in the Chicago area during the winter months is unlikely we still recommend year around prevention. Most heartworm preventatives also protect pets from intestinal parasites, which are diagnosed year around and can be passed to humans.

Here at our clinic we recommend Sentinel & Revolution as our primary heartworm preventatives. Sentinel is a dog product that is given orally every 30 days. It prevents heartworms, intestinal parasites (roundworms, hookworms, whipworms), and flea infestations. It is one of the most broad-spectrum preventatives on the market and that is why we currently recommend it over the very popular Heartgard. Revolution is both a canine and feline product. It is topically applied every 30 days. It too is a broad-spectrum preventative. We strongly recommend this for cats, and it is also available for dogs. Ask your veterinarian which option would be best for your pet.


Drew Sullivan, DVM