5. Address the envelope. In the lower right third of the envelope, write the name of the person you are sending the letter to. Write the company name on the line below that (if there is a company name).
Once inside a new host, it takes approximately 6 months for the larvae to mature into adult heartworms. Once mature, heartworms can live for 5 to 7 years in dogs and up to 2 or 3 years in cats. Because of the longevity of these worms, each mosquito season can lead to an increasing number of worms in an infected pet.
Heartworms are parasites that live in the blood vessels and heart of dogs. Sometimes cats are infected with heartworms too. Because heartworms live inside the heart, too many of them can cause the dog's heart not to work very well and the dog can get sick. In small dogs and cats even a few worms can cause a big problem. Dogs get heartworms when an infected mosquito bites them.