Heartworm disease is caused by parasites that stow away in mosquitoes.

When an infected mosquito bites your dog or cat, the parasites are injected and travel to the heart. That’s where they grow into large worms that cause big problems. Heartworm disease is often fatal if left untreated, and even the treatment can be dangerous.

The incidence of heartworm infection is increasing in the United States, thanks to mosquito-friendly environmental changes and the movement of infected wild and domestic animals.

The American Heartworm Society recommends testing dogs annually for heartworm. Both dogs and cats should be on medications to prevent heartworm disease year-round. Not all flea and tick medications work against heartworm, so discuss options with your veterinarian.

Remember, mosquitoes sometimes get inside the home, so don’t forget to treat indoor pets too!