Heartworm is a parasite commonly found in dogs and can be fatal if not prevented or treated. Larvae are transmitted to a dog via a mosquito bite and eventually find their way into the heart and respiratory system. Once the larvae have reached the heart, they begin to grow and do their damage. Heartworm parasites have a slow growth cycle and perform their destructive work over a long timeframe. It can be years before the signs are noticed, and by then it may be too late. Treatment may be possible, but the damage to the heart is usually significant. It's best to engage in preventative measures to make sure your dog is kept healthy and free from heartworm parasites.
What is Heartworm?
Heartworm, also called heartworm disease, is a type of roundworm known as dirofilariasis. The parasite that causes the disease is known as Dirofilaria immitis. It takes six to seven months for larvae to mature to adulthood where it begins the reproduction cycle. A single adult heartworm can reach up to 12 inches in length and live up to seven years.
How Does a Dog Get Heartworm?
Mosquitoes carry the immature larvae of the heartworm in their gut. When an infected mosquito bites a dog, it injects the larvae into the dog. From there, the larvae find their way to the heart, major blood vessels, and lungs. Upon lodging, the larvae begin to grow and reach maturity over the better part of a year.
What Happens to a Dog With Heartworm?
A dog with heartworm will lose its energy levels and become more lethargic over time. This loss of energy is the direct result of the blockages and damage that the adult heartworms are conflicting on the internal organs. A dog with advanced heartworm disease can experience sudden death in the form of heart failure or pulmonary thrombosis.
Testing for Heartworm
Veterinarians can test for heartworm by taking a blood sample from a dog and testing it for heartworm proteins. If no proteins are present, the dog is considered to be free from infestation. In the event there are proteins, the veterinarian will have more tests done to confirm or invalidate the diagnosis.
Treating Heartworm Disease
When a veterinarian determines that a dog is a good candidate for treatment, he or she will ask that the dog be kept quiet and not exercised while the medications are being administered. A typical treatment regimen involves three injections of melarsomine to kill the adults, a preventative medication to kill the juveniles, and supportive medications to reduce the potential of an adverse event from side effects.
Preventing Heartworms in Dogs
Heartworm prevention is straightforward and simple. All it takes is feeding a single dose of medication on the same day of each month to prevent heartworms from taking hold. The active ingredients in heartworm medications have been in use for decades and are known for their ability to eliminate adults and larvae. Parasites have been unable to develop a resistance to the active ingredients of ivermectin and pyrantel since their introduction and remain vulnerable to their eradicating properties. It’s important, therefore, to discuss a heartworm test and preventative heartworm medication with your veterinarian for your pet every year.