West Nile Virus FAQ's

The following information is taken from the American Heartworm Society. Since the first diagnosis of canine heartworm disease over one hundred years ago, heartworm infection has been widely recognized throughout the world as one of the major health problems affecting pets today.

Heartworm infection is caused by worms ( Dirofilaria immitis) that may grow to be 14-inch-long adults. These adult worms live in the right side of the heart and the arteries of the lungs. Heartworm infection can cause serious damage to these arteries, eventually leading to heart failure, and in severe cases, damage to other organs such as the liver and kidneys. Dogs of any age and breed are susceptible to contracting heartworm disease.

While cats appear to be more resistant to heartworm infection than dogs, with fewer worms surviving into adulthood, they are still susceptible to infection and can also suffer from the effects of heartworm disease. However, they do not contribute significantly to spreading the infection.

Although the risk of heartworm infection varies from state-to-state, heartworm disease has been identified in all of the contiguous 48 states and Hawaii.

Heartworm infection is spread from animal to animal by mosquitoes. Dogs, cats, ferrets, coyotes, foxes, wolves, sea lions and even humans have all been found to be infected by heartworm. Adult female heartworms release their young, called microfilariae, into the animal's bloodstream. Mosquitoes then become infected with microfilariae while taking a blood meal from an infected animal. During the next 10 to 14 days, the microfilariae mature to the infective larval stage within the mosquito. When the mosquito bites another dog, cat, or other susceptible animal, the infective larvae enter through the bite wound. In dogs, it then takes a little over six months for the infective larvae to mature into adult worms that may live for five to seven years in dogs. In cats, it takes about eight months to mature into adult worms that live from two to three years. Microfilariae cannot mature into adult heartworms without first passing through a mosquito.