Heartworms can and do infect cats. The disease is caused by the same worm, Dirofilaria immitis, that infects dogs. Heartworms will infect cats of any age, sex, or breed and can infect
indoor as well as
outdoor cats. Cats are usually infected with only a small number of worms (usually five or fewer); however, even
only one worm can cause clinical signs and even death in an infected cat. Diagnosis of heartworm disease in cats is tricky, and no good treatment exists. With topical applications available that prevent
heartworms, intestinal parasites, such as hookworms and roundworms, ear mites, and fleas,
why not prevent it?!
Clinical Signs:
- Coughing
- Diffuculty Breathing
- Vomiting
- Death
Diagnosis:
- Heatworm testing in cats can be difficult & unreliable.
- Antigen test: Detects adult female worms. If negative, this does not rule out heartworm disease. The cat may have 1-2 worms (too low to detect), immature worms, or may actually be infected with male worms. A positive test is accurate.
- Antibody test: Detects circulating antibodies to heartworms. A postive test proves that the cat has been exposed to heartworms sometime in it's lifetime. It may not have concurrent disease. An antibody test is often performed in combination with an antigen test. A negative test strongly weighs against disease, but may mean that the cat has not had enough time to create antibodies to the heartworms.
- Microfilariae testing: The veterinarian checks a blood sample for heartworm larvae. This test is unreliable, but if microfilariae are found, then disease is present.
- Thoracic radiographs (chest x-rays): Helps support the diagnosis of heartworm disease and can help the veterinarian assess the severity of infection. Radiographs may also aid the veterinarian on monitoring the patient for progression or regression.
- Echocardiogram: Actual heartworms may be seen with this method.
- Complete Blood Count (CBC), Serum Biochemistry, & Urinalysis: This may be supportive of the diagnosis, and may help address the severity of the disease in the patient.
- Tracheal Wash or Bronchoalveolar Lavage: The veterinarian actually looks at samples from the respiratory tract under the microscope to help support disease.
- Electrocardiogram (ECG): The patient with heartworms disease may have an abnormal ECG.
Treatment:
- NO GOOD TREATMENT EXISTS!
- Adulticide therapy in cats is not usually performed because complications may be severe. The death of even one worm can kill a cat.
- Treatment with steroids and supportive care is a common treatment in cats with heartworm disease. Supportive care may include supplemental oxygen, IV fluids, asthma medications, heart medications, antibiotics, and/or heparin therapy. Your veterinarian may recommend thoracic radiographs to monitor response to therapy.
- Surgical removal of adult heartworms can be performed, but is risky and usually reserved for severe disease.
- A heartworm positive cat is at risk for severe respiratory distress and death even with supportive care.
Prevention:
- It is much cheaper, easier, and SAFER to PREVENT the disease than to have to treat it! Not to mention heartworm disease kills.
- Several different medications are available to prevent heartworm disease. These will also prevent intestinal parasites that are contagious to humans, so it is also to your family’s benefit that your pet be protected. Many will also prevent flea and ear mite infestations!
