Coxsackie virus in Southern California; isolation of a strain from stools of a patient.

Thirty-three stool specimens from 29 patients were examined for Coxsackie virus by the inoculation of suckling mice. Such a virus, designated "California I," was obtained from two stool specimens collected on successive days from a patient with so-called nonparalytic poliomyelitis. Neutralizing antibodies for the California I strain of Coxsackie virus could not be demonstrated in serum obtained from the patient early in the illness, but were present in convalescent serum.Serum from the patient's daughter, who previously had had a similar illness, neutralized the strain of virus isolated from the father. In pathologic examination of the skeletal muscles of mice infected with the California I virus, lesions typical of those produced by Coxsackie virus, group A, were noted. California I strain of the virus was not neutralized by immune serum prepared from several other strains of Coxsackie virus.