Abstract
The Wallingford virus, isolated from the nervous system of a fatal poliomyelitis case in California in 1934, has been successfully passaged in cotton rats and in mice. Material from each of 2 paralyzed cotton rats produced typical poliomyelitis in one rhesus monkey. The virus has been tested for immunological relationships by inoculation in monkeys vaccinated with, and shown to be immune to, the Lansing and the Brunhilde viruses, respectively. These 2 viruses are representatives of 2 distinct types of poliomyelitis virus. The Wallingford virus is indistinguishable from the Lansing virus by the vaccination-immunity test and unrelated to the Brunhilde virus by the same test. The relationship between the property of rodent infectivity and the immunological specificity of the Lansing group of poliomyelitis viruses is discussed and evidence presented for the existence of three distinct immunological groups of poliomyelitis viruses, only one of which has thus far been shown to be infective in rodents.