Feline distemper is caused by a parvovirus and causes a disease called panleukopenia. This causes a severe decrease in all the white blood cell lines. It is contagious between cats but is not zoonotic (transmissible between animals and people). This is a preventable disease so cats should be vaccinated. Here is a link to more information regarding this disease:
www.VeterinaryPartner.com
www.VeterinaryPartner.com