Most dog owners are at least somewhat aware of heartworms. These are parasites carried by mosquitoes, and can be fatal. The worms are around 10 inches long when mature, filling the heart and vessels leading to the lungs with up to 30-50 worms. This can cause severe inflammation in the lungs, and lead to congestive heart failure. Dogs with advanced heartworm disease die slowly and painfully. Luckily, this can all be prevented with a monthly pill and annual testing. The testing is important because in the early stages of the disease there are no outward signs or symptoms.
But did you know that dogs aren't the only ones susceptible to heartworm disease? We are seeing an increase in the number of cases of heartworm disease in cats. It's been known for years that cats can contract the disease, but we as veterinarians haven't done a good enough job of letting clients know about this. Heartworm disease is different in cats than in dogs. Felines are naturally more resistant to heartworms than dogs, but they're not immune. Cats also get different symptoms than dogs, and it takes fewer worms to cause serious illness. Additionally, it's much harder to diagnose heartworms in cats than in dogs.
Ferrets are another pet that can get heartworms, and are as susceptible as dogs. However, like cats, it's hard to detect it. That's why most veterinarians don't require annual testing in species other than dogs.
Heartworm disease has been diagnosed in every state in the US, though since it's carried by mosquitoes, the incidence is higher in locales with high heat and humidity. Just because you live in a desert state, or a state that gets very cold winters, doesn't mean that you don't need to put your pets on prevention. No matter what the situation, prevention is better than treatment. Depending on the size of your pet, prevention will cost anywhere from about $40-80. Treatment for a dog can cost $800-1000. There is no approved treatment for cats or ferrets (which is why I tell my clients that though cats are less likely to get heartworms, if they do become infected it's a much worse situation than in a dog).
There are many different brands of heartworm prevention for dogs, and every vet will carry some. There are also several different brands approved for cats (Advantage Multi, Heartgard, Revolution, and Interceptor), and every cat should be on it. Personally, I prefer the topical preventions in cats due to the difficulty in getting a cat to eat a pill. Heartgard (and similar products like Iverhart, Wormshield, and many others) is safe to give ferrets, though not specifically approved.
So regardless of whether you have a dog, cat, or ferret, your pet is at risk of contracting heartworm disease. Do you really want this to happen? If not (and I hope that's your answer), see your vet right away.