Education
Feline Heartworm
How are heartworms transmitted?
Heartworms can only he transmitted from one animal to another by mosquitoes. Adult worms living in the heart and arteries of the lungs produce microfilariae (small immature heartworms) which are found circulating in the blood of the infected animal, usually a dog.
If a mosquito feeds on an infected dog with microfilariae in the blood, the mosquito will ingest some of these immature heartworms along with the blood meal. inside the mosquito, the immature heartworms develop to a stage called the infective larval stage. When the mosquito feeds on another dog or a cat, some of these infective larvae will escape from the mosquito during the blood meal. The larvae pass through the animal's skin through the bite wound left by the mosquito. Once the infective larvae have entered an animal, they will begin migrating through the tissues. They eventually make their way to the heart and lungs where they will mature and begin producing microfilariae.
How does my cat get heartworms?
If your cat lives in an area where heartworm infection is seen in dogs, your cat could be bitten by a mosquito that was infected by a dog.
What are the signs of heartworm disease in cats?
In cats, heartworms live for 1 to 2 years and it is uncommon for cats to have more than 2 or 3 adult heartworms.
Small numbers of heartworms, however, may cause serious disease in cats.
Clinical signs of heartworm disease in cats vary considerably. Some cats do not show any significant clinical signs and may appear normal. Other cats develop chronic (long lasting) disease. Vomiting or respiratory signs (coughing and difficult breathing) are commonly seen in chronic cases of heartworm disease in cats. Vomiting tends to be sporadic and may or may not be related to eating. Coughing may he intermittent or occur in severe, sudden attacks that may take place days apart. Cats may have severe, acute disease with signs of respiratory collapse and, in some cases, sudden death. In acute cases, death may be so rapid that there is insufficient time to make a diagnosis or offer treatment. Cats that die from heartworm disease can appear clinically normal the hour before death.
Many other diseases can cause similar clinical signs so it is almost impossible to diagnose feline heartworm disease based the clinical signs alone.
How do I know if my cat has heartworms?
If your cat lives in an area where heartworms are seen in dogs or if your cat is showing signs suggestive of heartworm disease, you should take your cat to your veterinarian. Because the clinical signs of heartworm infection in cats are also seen with other diseases, your veterinarian will probably need to perform diagnostic tests in addition to conducting a thorough physical examination. Many diagnostic tests, such as radiography (x-rays), ultrasound (If the heart and lungs, anti blood tests, including a new in clinic test developed specifically for diagnosis of heartworm infection in cats, are helpful in diagnosing the disease. Consult your veterinarian.
My cat is an indoor cat, Can it be infected with heartworms?
Cats that remain indoors are at lower risk of becoming infected than are cats that are outdoors because of the reduced exposure to mosquitoes. Despite this, heartworm infections have been reported in strictly indoor cats; these infections are caused by infected mosquitoes that entered the house.
Should I get my cat tested for heartworm infection?
If you live in an area where heartworms are seen in dogs, or if your (at has signs suggestive of heartworm disease, you should consult your veterinarian to discuss having your cat tested. If your cat is heartworm positive and develops clinical signs, see your veterinarian immediately.
When do veterinarians recommend testing for heartworms?
Your veterinarian may recommend testing in any one of the following situations:
Prior to prescribing a heartworm preventive
As a presurgical screen
When monitoring a preventive program
When your cat is sick
When monitoring a cat with heartworm disease
Can feline heartworm disease be prevented?
Preventives are available for feline heartworm infection, but they will not eliminate an existing infection. Preventives can be used on cats that test positive, to prevent further infections.
What can be done if my cat has heartworms?
Unfortunately, treatment to remove heartworms from infected cats can be difficult and hazardous to your cat's health. Various medications can he used to help minimize the clinical signs (coughing, vomiting, difficulty in breathing) your cat may be exhibiting. Surgical removal of heartworms is also an option. See your veterinarian for advice on management of feline heartworm disease.