heats up. My sister's 11 yr. old cat just died from what we think must have been heartworm. He was born outdoors to a feral mother but had been an indoor only cat since he was rescued in kittenhood. Last week, he had a seizure or episode, and then he fell over and died right in front of us. He had been taken to the vet on 2 previous occasions because of what appeared to be seizures, but vet said that "bloodwork is normal. Cats rarely have seizures." I filmed part of this episode and the experts that viewed it, including vets and vet techs posted that it "looks like a cat with hypertrophic cardiomyopathy or heartworm disease. And also, cats can have seizures, I have treated them myself. Its not as common as with dogs, but it does happen. Unfortunately, no matter what diagnosis was made, there probably was nothing you could have done for this poor baby." and
"Sadly, we cant really test for heartworm in cats. The test is for the female heartworm uterine antigen (yes, I know, very specific). Since cats are an aberrant host, they usually only have a single worm, and therefore rarely will test positive."
https://www.livescience.com/17363-heartworm-cats-fatal-nsf-ria.html
Just an FYI and heads up to those cat people who live in areas where mosquitoes are ever-present.