Feline Heartworm Disease

Heartworm disease has been a serious threat to dogs in the Gulf Coast area for many years. Now, recent research studies indicate that the threat is increasing for cats as well. In the past, we have seen very sporadic cases of aberrant (abnormal) heartworm disease in cats; however, increasing frequency of diagnosis and clinical significance of the disease have led to research studies that indicate several alarming facts.

1.	The incidence of heartworm disease in cats, which was once thought to affect approximately 1-2% of cats in the Gulf Coast environment, is now believed to be as high as 10-20%. The Gulf Coast area has one of the highest rates of feline and canine heartworm disease in the nation.
2.	The incidence of heartworm disease in cats appears to be rising, indicating that heartworm disease is an emerging (new) disease incats and is rapidly becoming a significant and increasingly common clinical problem.
3.	Heartworm disease affects cats in a much different manner than it affects dogs. Chornic mild coughing, chronic intermittent vomiting, weight loss, and acute agonal death without prior signs of illness are the four most common signs of heartworm disease in cats.
4.	Indoor cats appear to have as high an incidence of heartworm disease as outdoor cats, for reasons that are currently unknown and under study.
5.	Diagnosis of heartworm disease in cats is difficult, andmany cats appear to be normal until stricken with an acute respiratory failure/death syndrome.
6.	Management of heartworm disease in cats is very different from in dogs, but current therapy rcommendations appear to be beneficial in preventing serious consequences of the disease, especially the acute death dyndrome.
7.	A once monthly heartworm preventative medication has been developed and approved for use specifically in cats, and a rational heartworm testing protocol has been developed for cats.

Based upon these new developments concerning feline heartworm disease, many vets believe that heartworms should be addressed in all cats (both indoor and outdoor) in the Gulf Coast area. Because of the increasing indicence of feline heartworm disease, many vets have begun to integrate heartworm testing and prevention as a standard component of routine care for cats.

Initially, a blood test is performed to detect prior exposure to heartworms. If the test is positive, a second test will be performed in an effort to detect adult heartworms in the patient. If positive, radiographs of the chest and/or an individualized course of therapy will be recommended. If negative, once-monthly medication to prevent development of heartworm in the cat is recommended. Because of the character of the disease, difficulties with its diagnosis, and FDA prescription labeling of the preventative, an annual blood test is required to confirm the heartworm status of your pet. This procedure is critical to minimize the potential for "missed" cases that may ultimately lead to clinical manifestations of the disease if not addressed.

If you have any questions concerning feline heartworm disease, or any other aspecvt of your cat's health, don't hesitate to contact your veterinarian. Heartworm disease prevention in cats is rapidly becoming an integral part of rfeline heatlh care, as it has been id dogs for many years. Standards in pet health care, as in human health care, are constantly being updated and revised based upon new research and clinical findings.

Kevin A. Kettler DVM
Dickinson Animal Hospital