Symptoms of Heartworms in Cats

Cats are typically not as susceptible to heartworm as are dogs. However, the condition is just as serious for cats, and can be fatal. All cats should be tested for heartworms. If their presence is not detected, take preventive measures to ensure that your pet remains protected against this significant health risk.

  1. Features

    • A heartworm is transmitted via a mosquito bite. Outdoor cats are more likely to become infected with heartworms than indoor cats. However, indoor cats are not completely protected, and may be bitten by a mosquito that enters the house. Heartworms live in the right side of the heart and/or the pulmonary arteries (the arteries leading to the lungs). A heartworm cannot be transmitted from one cat to another.

    Significance

    • The heartworm normally has a relatively short lifespan: 2 to 3 years in cats, as compared to the 5 to 7 years in dogs. The cat's immune system produces an antigen to fight against heartworms in their pre-larva stage. Dogs do not produce the antigen, which likely accounts for the increased percentage of heartworms in canines. Cats usually develop a significantly smaller amount of heartworms than dogs.The amount of adult worms found in cats is usually 1 to 3, but even one worm can be enough to cause death in a feline. Although cats produce the antigen, felines with a weakened immune system are more susceptible to developing mature heartworms.

    Effects

    • Cats that are infected with heartworm may exhibit symptoms that indicate respiratory distress. Some cats show no symptoms at all, and may die suddenly without any sign of illness. This may occur when the heartworms block the arteries, obstructing blood flow to the lungs. The most common symptoms of heartworm are coughing, rapid breathing, weight loss, vomiting and lethargy.

    Considerations

    • Blood tests and X-rays are used to detect the presence of heartworm. One blood test detects antibodies in the blood that are produced by the cat's immune system. An antigen test detects proteins in the blood that occur from the breakdown of the worm. An ultrasound is often used to produce an image of the heart and pulmonary arteries.

    Warning

    • There is no approved medication for heartworm treatment in cats. Although medication is available that can be used to treat dogs, it can have serious side effects when used in cats. It can even be fatal to felines. A veterinarian will decide whether to treat the cat, based on its clinical symptoms. If the cat is showing no symptoms, it may be best to wait it out, since some cats outlive the worms. If the cat is displaying signs of distress, the treatment is usually supportive. Veterinarians sometimes administer steroids like prednisone to reduce the inflammation of the lungs.

    Prevention/Solution

    • Preventing heartworm is imperative for cats and their owners, since there is no effective treatment. Several medications, including Heartguard and Revolution, can be given to cats and kittens 6 weeks of age or older. Administer these medications monthly to prevent heartworm. Although it is still debatable whether preventive medicine should be performed on indoor cats, it is recommended for cats that go outdoors, since they may be at a higher risk of developing heartworm. Prevention is the best medicine, and by taking the proper measures to protect your cat, you could ultimately save its life.