How contagious is panleukopenia in cats, and what's the fatality rate?

Quick answer

This is an infectious disease caused by a parvovirus, and it's severe enough to have up to a 90% fatality rate in kittens with weaker immune systems. It comes with severe vomiting, bloody diarrhea, high fever, and lethargy. The only reliable prevention is keeping up with the core combination vaccine on schedule to build antibodies in advance.