Many people have heard of heartworm disease in dogs, but not everyone is aware that pet cats and ferrets are also at risk of developing this potentially fatal disease. Heartworm disease is caused by a parasitic worm (Dirofilaria immitis) that is transmitted via mosquito bites. In brief, the mosquito bites an infected dog and sucks up some of the heartworm “babies” (microfilaria) and then when the mosquito bites another dog, cat, or ferret this baby stage is transferred to this animal’s body. Over the next 6 months these young worms (now larvae) migrate through the host animal’s tissues and make their way to the heart. In the heart they mature and may reach lengths of up to 10 inches.

Ferrets have very small hearts and even one adult worm can result in serious illness. The worms not only interfere with the normal pumping function of the heart, but small fragments may break off and travel to the lungs where they can cause serious lung disease.

All ferrets in “endemic” areas of heartworm disease are at risk. An endemic area is an area where the climate supports enough mosquitoes to keep the disease cycle going. In the United States these especially include areas within 150 miles of the Gulf and Atlantic coasts and along the Mississippi River and its tributaries. Your veterinarian can tell you whether you are in such an area. Even indoor ferrets are at risk as mosquitoes may come inside the house.

Heartworm disease can be treated but the disease is very serious and the treatment is risky and expensive.

Prevention of heartworm disease in your pet ferret is easy, effective, safe and cost-effective. There are several drugs that may be suggested by your veterinarian. Ivermectin and selamectin are the most commonly used drugs to prevent heartworm disease. They may be dispensed as an oral liquid, chewable pill or topical ‘spot-on’ and are given or applied monthly.

Please ask your veterinarian about heartworm testing and prevention.