A woman, possibly a veterinarian, wearing glasses and a headband gently holds a Cavalier King Charles Spaniel on a veterinary exam table. The woman smiles at the calm, curious dog. Her jacket proudly displays an "AAHA Accredited" patch.

Spring is here, and along with April showers and warmer temperatures, comes an increase in mosquitoes! April is “Heartworm Awareness Month,” and it’s the perfect time to make sure your pets are up-to-date on their heartworm testing, treatment, or medication.

Heartworm disease is a serious and potentially fatal disease in pets in the United States and many other parts of the world. It is caused by foot-long worms (heartworms) that live in the heart, lungs, and associated blood vessels of affected pets, causing severe lung disease, heart failure and damage to other organs in the body. Heartworm disease affects dogs, cats and ferrets, but heartworms also live in other mammal species, including wolves, coyotes, foxes, sea lions and—in rare instances—humans.