Virus, J. C. (JC virus) name a species of file that in the year 1965 with the use of the electron microscope was discovered. This virus, named from the first letters of the name "John Cunningham" (the disease that the virus from the body, the cultivation of thought) takes place. This virus causes disease, " progressive" (PML) in people who suffer from immunodeficiency (e.g. AIDS patients or recipients of the medicines weaken the immune system following an organ transplant) are offered.