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.
How heartworms are spread. All dogs are at risk for potentially deadly heartworm disease. Heartworms live in the heart and blood vessels of the lungs of dogs, cats and other mammals like wolves, foxes and coyotes. Heartworms cannot be spread directly from animal to animal without a mosquito as an intermediary.