The adult heartworm is a parasitic worm that inhabits the heart chamber. It is not found in the intestine and is not eliminated in feces.
To test for heartworm, your veterinarian will recommend an annual or semiannual blood test. There are several different methods of analyzing the blood sample. Prevention is even more important for heartworm than for intestinal parasites because the consequences of heartworm infestation are so much more life threatening. Medication to prevent heartworm disease is available through veterinarians but can only he administered to dogs that have tested to be free of heartworm. A dog with heartworm that is given the heart-worm, preventative could have a fatal reaction.
Heartworm treatment is available, but it must be closely supervised and can take many months before your dog is declared healthy. The treatment itself is not without risk as adult worms and larva killed by the treatment die inside the heart and blood vessels. Side effects are relatively common even during successful treatment, and dogs usually require hospitalization as a precaution. The majority of treated dogs recover well.
The life cycle of the heartworm takes place almost entirely in the circulatory system of the infested animal. It is transmitted in an early larval stage by the mosquito. When a mosquito bites a dog with heartworm larvae in the bloodstream, they are harbored by the mosquito until it bites another victim. When a mosquito bites an animal, the mosquito initially expels some saliva that keeps the victim’s blood from clotting. It is at this moment that a heart-worm larva is also expelled to continue its own life cycle inside the animal.
Heartworm preventative pills are usually given mice monthly on the same calendar day of every month during mosquito season. Because there is al- ways even a remote risk of mosquitoes, more and more veterinarians are advising heartworm pills year-round. Many pet owners forget to go in for the heartworm test or become confused as to when to start and when to stop these pills. If you have stopped the heartworm pills for any reason, the blood test must be repeated. It can be simpler and safer for most pets and their owners to practice prevention throughout the year.