Feline (Cat) Heartworm Disease Update

Did you know that heartworms can infect cats (felines)? 

Dogs (canines), coyotes, and foxes are the natural hosts for this potentially lethal, mosquito-transmitted, parasitic worm.  But, cats can be infected too. While the incidence of infection in cats is lower than with dogs, newer studies have shown a greater percentage of feline cases than was previously thought.

In dogs, typical clinical signs can vary from no signs of illness to coughing, difficulty breathing, and exercise intolerance (fatigue).  Once infected, the worms localize in the heart and blood vessels of the lungs.  Since dogs can frequently tolerate large numbers of worms, they oftentimes don’t show severe signs until their disease is quite advanced.  Once it is advanced, if it is left untreated and/or it is too severe, death can result.

In cats, clinical signs include coughing, difficulty breathing, exercise intolerance (fatigue), and vomiting.  And, unlike with dogs, oftentimes acute death can occur with no previous signs of illness.  Furthermore, with cats, even an infection of just 1 or 2 worms can have fatal consequences.  And yes, since mosquitoes are the transmitter (vector) of the disease, indoor cats are at risk too.

While our prevalence of heartworm disease in Santa Barbara County and Southern California as a whole is still lower than most areas of the country, researchers are discovering that our coyotes, mainland foxes, and Channel Island foxes are increasingly being found to be infected.  And, with so many people and their pets moving here from heartworm infected areas of the country, this is another potential reservoir for infections. This means our pets are much more at risk to become infected too.  Therefore, we recommend providing the same preventative care for our feline patients as we do for our canine patients. And, this would apply for our ferret friends too.

To do this, a heartworm test is recommended for all cats older than 4 months of age (just like with dogs).  If the test is negative, your pet should be placed on a heartworm preventative.  Thereafter, the Heartworm Society recommends a yearly heartworm test for all cats (and dogs).

While there are a few different preventative medications to choose from for heartworm prevention in cats, we are currently recommending topically applied Revolution or orally administered Interceptor.  Both medications are administered on a once-a-month basis.

Besides preventing heartworm infection, both Revolution and Interceptor also treat for two gastrointestinal (GI) parasites (roundworms and hookworms).  In addition, Revolution kills fleas and ear mites.

If you are concerned about ticks, Revolution or Interceptor can be used in conjunction with Frontline.

If you have any questions pertaining to this information or to any aspect of your pet’s health care, PLEASE FEEL FREE TO ASK US.