Information on the cause of heartworm disease and symptoms like coughing in cats and dogs

What is Heartworm?

Heartworms are deadly parasites that affect dogs and cats, as well as other animals. These worms are also referred by their scientific name Dirofilaria immitis and actually live in the right side of the heart and arteries of the lungs. It causes a serious condition that includes heart failure, blocked arteries and breathing difficulties. When a mosquito bites your dog or cat, your pet may be infected with heartworms.

Heartworms are thin, long (about 12 to 30cm) worms and have an adult lifecycle of 5 to 7 years for dogs while in cats, it is between 2 to 3 years. During this time millions of larvae are produced but they only become fully matured after living in the mosquito.

In addition, there may also be symptoms of anemia, swollen abdomen, jaundice, bulging chest and prominent ribs. Convulsions, rapid heartbeat, diarrhea, vomiting and in the advanced stages, heart failure or clotting in the pulmonary arteries may occur.

What Causes Heartworm?

When the mosquito bites an infected dog or cat, it ingests the larvae and if that mosquito bites another dog or cat, it transfers the larvae. Over the next few months, the larvae migrate through the body of the animal until it reaches the heart and matures into an adult worm. Female worms cause more damage than male worms.

Infections of heartworm are usually quite common in warmer countries of the world. Research shows that dogs are affected more than cats - in particular, large-breed dogs, male dogs as well as dogs with short hair and stray dogs and those that stay out of doors. Certain factors may also increase your pet’s risk of heartworm disease and these include genetic factors, location of the heart where the worms are, if there are more male or female worms, length of time and the number of worms present.

Diagnosing Heartworm

The diagnosis of heartworm is based on the symptoms presented, a thorough physical examination and a review of the pet’s medical history. Certain tests such as chest x-rays may be performed to determine whether the pulmonary arteries in the lungs are enlarged, as well as antigen and microfilarial tests to detect the presence of adult heartworms.

Help for Heartworm

There are a number of oral and topical heartworm preventatives such as Heartgard or Interceptor available to treat dogs and cats, and these can be administered once per month. These medications help to prevent the microfilariae (larvae) from developing into adult heartworms.

Because dogs and cats that live outside are more susceptible to heartworm, it is recommended that they receive this treatment monthly. Indoor pets, however, still remain at risk. Keep in mind that these medications have toxic side effects and have been linked to serious disorders such as liver and kidney disease, arthritis and skin allergies.

Heartworm in dogs is treated with an adulticide, medication administered to kill adult worms over a period of a month. After the one month period filaricide therapy which involves the administration of microfilaricide to kill the microfilariae.  Treatment for heartworm in cats has not been approved as yet and involves treating the symptoms with intravenous fluids, oxygen therapy, bronchodilators or confinement.

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