 The Goal of Heartworm Meds
When Heartworm meds first came on the market, it was given as a daily dose, to keep the dog free of heartworm. Researchers have learned that the heartworm really doesn't hurt the dog until it reaches the dog's heart and multiplies. This takes 7-9 months to happen. Therefore, the medication developed for the dog has to kill the heartworm babies (larvae)as they are growing in the dog's skin (tissue), which happens after the dog is bitten by an infected mosquito. Not all mosquitos are infected with heartworm. They live and grow in the dog's skin for 2 months. This is called the 'Tissue stage', and is a good time to get rid of them. If you give them one dose of heartworm medication formulated to kill tissue stage larvae at least once every 2 months, you are killing the tissue stage larvae living in your dog's skin. The companies that make the Heartworm medicine decided it would be easier for people to remember once a month than to remember once every other month, and if one forgets, you still are safe by a month.
If you live in an area where there are many heartworm cases, it is more likely that your dog will end up being bitten by an infected mosquito at some point in his life. As long as he gets a dose of heartworm meds at least once every 2 months, the heartworms will never get to his heart. There may be days when live larvae are present in his skin. As long as these are killed before they reach his heart (within 2 months), he will be fine.
The goal is not to keep medication in the dog to kill the HTW Larvae all the time, but to give the medication once a month to kill the larvae before they leave the dog's skin to travel to the dog's heart, where the damage occurs. |