- Rabies (this can be spread to people)
- Feline panleukopenia (feline distemper)
- Feline herpesvirus infection
- Feline calicivirus infection
- Feline leukemia (FeLV)
- Feline immunodeficiency virus (FIV) infection
- Heartworm disease
- Intestinal worms (roundworms, hookworms, whipworms, tapeworms, etc., some of which can also infect people)