Dear Cathy: I read your column every Sunday and wanted to pass along something my vet said recently when I had one of my cats in his office for her shots. He was trying to sell me on heartworm prevention for my three cats (all indoor, but he says mosquitoes can get them there, too). I thought he was nuts, but he says new research shows that heartworms manifest in cats' lungs rather than their hearts, and that many vets suspect that what they historically thought was lung disease in cats might have actually been heartworms. He also said that, unlike in dogs, heartworms cannot be treated in cats, and that they will eventually die from the disease. Needless to say, my cats are now on heartworm meds.

I thought you might want to pass this information along to other readers.

— Susan Shaked

Dear Susan: Thanks for sharing your vet visit. Heartworm disease in cats was once thought to be too rare to warrant any testing or preventative measures. But recent studies now show that it is becoming a serious problem for our feline friends.

Heartworm disease is an infestation of the heart and lungs by a parasitic worm. When a mosquito bites an infected animal, it ingests some of the worm's larvae. The next time the infected mosquito takes a blood meal, some of those larvae enter the dog or cat's bloodstream and grow into long parasitic worms. While dogs can have hundreds of heartworms, felines may only have one or two, but sadly, that's all it takes to produce clinical signs that can result in a cat's death.

As you noted, coughing, respiratory problems, or even asthma-like symptoms are some of the warning signs. Some cats may show no signs at all, but can die suddenly from this disease. If you have a cat, talk to your vet about protecting your feline from heartworm disease.