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.
1 Dogs and cats should be on monthly heartworm medicine all of their life starting at about 12 weeks of age. 2  We recommend that dogs be started on Ivermectin Heartworm Preventative when they test positive for Heartworms as the Ivermectin will to some degree weaken the existing adult Heartworms. Your dogâs adult heartworms should now be all killed with the completion of Heartworm Treatment Part 1. 2  Heartworm Treatment Part 2 will now kill the baby heartworms called Microfilaria, which live and circulate in the bloodstream.