What, exactly, are heartworms?

In one of my recent blogs I mentioned Heartworm; an illness that can affect a variety of animals, but primarily affects dogs. Heartworms is a parasite that is transmitted through the bite of mosquitoes that have contracted microfilariae from biting an infected animal. Those microfilariae develop into larvae within the mosquito's body and are then transferred into the skin of a different animal when the mosquito bites them. The larvae uses its new host's skin to travel through its body and into its blood stream and ultimately ends up in its heart. Finally, the worms multiply in the heart until it's essentially clogged with them.

Symptoms, although generally minimal, aren't shown until about six months after the animal is infected, but there is a blood test that can be done that gives quick results. In fact, the test MUST be done and results MUST be negative in order for any sort of preventative can be prescribed. (This is because the preventative can and most likely will kill the dog if it's given to them when the dog is infected.) The veterinary clinic that I worked at had a three-in-one test that tested a dog's blood for heartworm, lyme disease and ehrlichiosis (other parasite borne illnesses).

If the the test is positive there is a treatment course available, but it's quite expensive, extremely hard on the animal and there's no guarantee that it will work. This treatment usually consists of a few days of arsenic based compounds being injected into the infected animal's body followed by a few weeks of inactivity to allow its body to absorb the dead worms. The time of rest is particularly important to the dog's recovery process because if it is too active, dead round worms are likely to be set loose and absorbed into its lungs, causing respiratory failure.

Overall, it's much more inexpensive and much less stressful to prevent against this parasite than taking a chance with your dog's health. There are a variety of preventatives on the market for this purpose and some that even include added protection against other parasites like fleas and ticks. Although, as mentioned earlier, a dog must be tested tested before being prescribed any type of medication for this purpose. Talk to your veterinarian to see exactly what their clinic's policy is on testing and preventatives as some places in cooler climates only require testing every other year and the preventative to be given in the warmer months of the year.