Cats and dogs get heartworms the same way from mosquitoes, which carry heartworm larvae.
Dogs are much more susceptible to the disease than cats.
No one really knows how prevalent the disease is in cats, though some estimates are that up to 17 percent of Kentucky cats may be infected with heartworms. Not every cat who has heartworms gets seriously ill from it, though. But prevention is important, some veterinarians say, because there's no effective treatment for serious cat heartworm infestation, as there is for dogs. During the past two years, two new preventive heartworm treatments for cats have been put on the market. In December, one of her two cats, Baby, started acting sluggishly.