What are heartworms?
Heartworm (Dirofilaria immitis) is a large worm that lives in the heart and pulmonary arteries of an infected dog. Dogs acquire this infection through mosquito bites as mosquitoes readily pick up larval heartworms from infected dogs and carry them to new dogs. Some geographic areas (especially the southern region) have severe heartworm problems, while other areas have virtually none.
How do monthly heartworm preventatives work?
All approved heartworm medications work by eliminating the immature (larval) stages of the heartworm parasite. Heartworms must be eliminated before they reach the adult stage since heartworm preventatives do not work against the latter stages of heartworm larvae or against the adult heartworms. Therefore, it is extremely important that heartworm preventives be administered strictly on monthly schedule.
When should my puppy or kitten be started on heartworm prevention?
Puppies and kittens are just as likely to get heartworm disease as adult pets, and thus puppies and kittens should be started on a heartworm preventive as early as the product label allows, and no later than 8 weeks of age. The dosage of a heartworm medication is based on body weight and not the age of the puppy or kitten. Since they grow rapidly early in life, a young animal can gain enough weight to bump it into a different dosage range within a matter of weeks. Because of this variable, we recommend you discuss the different types of heartworm prevention and dosage ranges with your veterinarian to determine what is best for your pet. This will ensure your puppy or kitten is properly protected against heartworms.