A Comprehensive Overview of Heartworm Disease in Dogs

Although heartworm disease is one of the easiest diseases to prevent in dogs, the number of canines being infected by such illness is on the rise in the US and even other parts of the world. The major reasons for the increase are negligence and ignorance by numerous pet owners throughout the country. A number of dog owners either have never heard of the disease or believe that no mosquito could penetrate the skin of their hairy dogs.

Despite graphic posters showing the hearts of infected dogs, which are often displayed on veterinary clinics, many dog owners still end up losing their canine companions to this disease primarily because they do not take precautionary measures that could help detect such illness in dogs at an early stage. They pass up heartworm tests no matter what veterinarians say.

Dirofilaria immitis, the medical term for heartworm disease, is actually a parasitic infestation of nematodes that is transmitted through a mosquito bite. Heartworm disease is rampant in places with high mosquito population and in areas near the Mississippi River, including its tributaries, and the Gulf and Atlantic coasts, according to data from the Heartworm Society.

Heartworm disease is present in all continents except Antarctica. Heartworms grow and breed in areas with a type of weather that sustains the life cycle of the parasite, a constant reservoir of the illness, a huge population of mosquito, and a huge population of susceptible dogs.

The temperature of over 80 degrees is the ideal climate required by the microfilariae, which are larvae of the parasites, to develop. Although an untreated dog cannot directly infect other susceptible hosts, such as other dogs, foxes, and even cats, it can serve as a reservoir for the propagation of the disease. Mosquitoes transfer microfilariae from an untreated animal to another.

Symptoms of heartworm disease

It takes several months, usually about six or seven, before adult heartworms reach the heart of the dog. Thus, you might not be able to detect that your dog is suffering from the disease even months after your pet has been bitten by a mosquito carrying the parasites. Symptoms usually appear when there are already numerous heartworm adults living inside the heart of your dog or even a year after the initial infestation.

Heartworms can grow up to 14 inches in length and can stay inside your dog's arteries, heart and lungs for years. However, symptoms usually appear earlier in active dogs.

The first sign of infestation is soft cough, which is usually dismissed by dog owners as cold symptoms. The cough may worsen when the number of worms in the dog's heart has reached an alarming level. As the disease develops, your dog may appear listless and weak. You will find that your dog is losing weight and gets tired easily. Sometimes, dogs faint even from slight exertion.

As the adult heartworms increases in number, the chance of your dog's survival gets slimmer. At the final stage of infestation, when over hundreds of heartworms enter the host's heart, complications like clotting problems, embolism, and organ failure will lead to your pet's painful demise.

Testing for the disease

In order to find out if your dog has heartworm disease, the animal must undergo some blood tests. The first test is filtration, which will determine if there are microfilariae in your pet's blood. The other test is an occult test, which detects adult worms in the heart. It is advisable to get both tests since the absence of the heartworm's larvae in the blood is not a guarantee that there are no adult worms in the dog's heart. Aside from blood tests, vets also find worms in the dog's heart and lungs by means of x-rays.

Treatment and Prevention

It is quite easy to get rid of the parasites when the infestation has not yet reached extreme levels. However, before any treatment is given to eradicate the worms from the dog's system, the veterinarian would first check the dog's condition and try to treat complications of the infestation, such as liver and heart failures, etc.

Two daily doses of arsenic compound or a new drug, which is safer for dogs, are usually given to dogs for two days. Dogs must not exert too much effort during the weeks following the ingestion of the drug. Too much exertion might cause the dead heartworms to travel to the lungs, which might result in suffocation.

After the adult worms have been eradicated, the dog will have to undergo a weeklong treatment for the killing of microfilariae in the blood. Your dog needs to undergo a series of blood tests and purging until all the traces of microfilariae and adult heartworms are gone.

If the infestation is already in its final stages, your canine companion might have to undergo surgery.

There are many medications, both topical and oral, that are available for the prevention of heartworm infestation. Just ask your veterinarian what drugs and other measures you could do to prevent your dog from getting such a debilitating, and often fatal, disease.