Heartworm Disease in Dogs

Filed Under: Dogs, Parasites

Heartworms can be a problem anywhere mosquitoes inhabit. This disease syndrome is especially prevalent in Florida and the other Gulf Coast States. Due to their mild climate, these states are pestered by mosquitoes year round.

A dog that has heartworms serves as the source of infection. A mosquito that bites the infected pet, and then bites another dog, cat or ferret, can spread the disease to the new host. Even humans can be affected by heartworms. Actual heartworm disease does not occur in humans; rather the heartworm will undergo a limited development, becoming encysted within the lungs of the human host. The encysted heartworm can be an insignificant finding on autopsy, or be confused with radiographic changes similar to neoplasia, and is termed “coin lesions.” Unfortunately, this confusion may result in unnecessary surgery or biopsy.

The original dog with heartworms has circulating microfilaria (baby heartworms) in its blood stream. These microfilaria or are inadvertently picked up by the mosquito. The larva then continues its development within the mosquito, finally maturing to the mouth parts of the insect. When the mosquito then feeds on a new pet, the now matured larva is injected from the mosquito’s mouth into the new host. The larva will then mature within the body of the new host, eventually developing into a spaghetti-type worm within the right side of the heart and pulmonary arteries.

Mature worms will affect the blood flow through the right side of the heart. Eventually, this disruption of the blood flow will result in Right Heart Failure.

Initial clinical signs of heartworm disease in the dog may be rather subjective. At first the pet may have a decrease in exercise tolerance, later developing a cough or fluid accumulation within the abdomen. Advanced disease may result in a pot-bellied appearance, weakness, difficult breathing, anemia and even death.

In addition to regular checkups at your veterinary clinic, if your dog exhibits any unusual behavior, please schedule an additional checkup with a heartworm test. Early preventative treatment may save your dog’s life.

Topics: heartworms

Symptoms: coughing, difficulty breathing, lethargy, swelling, weakness

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