Signalment: Smokey is a 6 year old Labrador Retriever mix.
History: Smokey was brought into the clinic for a routine castration, where he got Pre Anesthetic lab work and a heartworm test. The test showed up positive for heartworm. The in house test was confirmed with an out of house antigen test which came back positive.
Diagnosis: Heartworm positive. Dr. Alyssa Pogozelec sent Smokey home on an antibiotic called Doxycycline and Prednisone (a steroid). The antibiotic for Smokey is for bacterium that is found living on the heartworms called wolbochia. The co-infection is thought to contribute to an inflammatory response within the body. After the heartworms die they release the bacteria into the bloodstream.
Since the heartworm treatment only kills the adults, we are having the owners start Heartworm Preventative (Heartgard) to help kill the smaller larvae before initiating adult heartworm treatment. We are using the prednisone along with the antibiotic and heartworm preventive to help reduce inflammation. Once Smokey has completed the course of antibiotics and steroid, he is going to start the actual heartworm treatment, which is a series of 3 injections of immiticide. On the days Smokey gets his treatments he will stay in the hospital over night and also be on restricted activity the entire time of the treatment, plus 8 weeks after the final injection so....months! After 60 days, which is the amount of time it takes for the injection to kill the heartworm, he will need to get retested to make sure all of the larvae, microfilariae, and adult worms are dead.
Discussion: Heartworm is a very preventable disease, giving a monthly heartworm preventative after testing your dog if it is over the age of 6 months can decrease the risk of infection. Puppies as young as 8 weeks old can be started on monthly preventative. Giving heartworm preventative year round is highly recommended, and yes, even during the winter months. There are years that our winters are very mild and mosquitoes can come into your home and infected your pet without your knowledge of it happening. Testing is recommended every 2 years, even if your pet is on year round preventative as no preventative is 100 percent effective. Heartworm preventatives also protect against gastrointestinal parasites such as hookworms, roundworms, tapeworms and whip worms. Cats can also get heartworms, although it is less prevalent, they can get up to one to two heartworms but they are mainly female worms so there is no reproduction to cause more of an infection. Since the heartworm tests that we run in house only detect the baby heartworms, it is not very useful in cat heartworm infections.