Canine Heartworm Risk

Canine heartworm is a parasitic infection passed to dogs through the bites of infected mosquitoes. Canine heartworm disease is more common in warm, humid areas where mosquito activity is high, but it can occur anywhere mosquitoes are present. All dog owners should make sure their pets receive simple preventative treatments to avoid this often-fatal condition.

  1. Heart and Lungs

    • A fully infected dog can have hundreds of worms clogging the ventricles of its heart and the blood vessels that serve the heart and lungs.

    Symptoms

    • Dogs may not have symptoms until worms are mature. Infected dogs show symptoms that include coughing, difficulty breathing, exhaustion after mild exercise, lethargy and weight loss. Advanced symptoms are labored breathing, pale gums, dark urine and death.

    Effects

    • Dogs infected with heartworms can develop heart failure, blood clots in the lungs, inflammation of the circulatory system, liver and kidney failure and accumulation of fluid in the abdomen. Caval syndrome is a severe blockage in the right side of the heart caused by an accumulation of worms. It can stop the flow of blood to the brain and heart, which can prove fatal.

    Treatment

    • After a positive heartworm antigen test, dogs are treated with an injection of melarsomine hydrochloride under the brand name Immiticide. Worms are killed within a few days. Risk of cardiopulmonary complications remains high for a few weeks as the worms break down in the bloodstream and the fragments move into the lungs and capillaries. Exercise should be limited for a month or two.

    Prevention

    • Monthly canine heartworm medications are the most effective preventative measure. They're also the most popular because of their convenience. Many anti-flea treatments also discourage mosquitoes from biting and transmitting canine heartworm larvae.

    Tip

    • If you suspect your dog has canine heartworm disease, don't try to treat it without a veterinarian's supervision. Diagnostic tests should be done to confirm the illness is caused by canine heartworm and not another parasite or disease.