[Isolation of type 71 enterovirus from patients with a poliomyelitis-like disease during an outbreak in Bulgaria].

Virological examinations of 72 specimens obtained during an outbreak of a poliomyelitis-like disease in Bulgaria, 1975, yielded 23 strains of enterovirus type 71 (E71) and 5 strains of enteroviruses of other types. The viruses were isolated in green monkey kidney cell cultures, in newborn cotton rats, newborn white mice and in monkeys. Most of E71 strains (16 out of 23) were isolated from the autopsy materials (brains and spinal cords) from 9 children dying of poliomyelitis, meningoencephalitis, and encephalitis. The remaining E71 strains and all the strains of other enterovirus serotypes, with the exception of ECHO7, were isolated from stool specimens of children with aseptic meningitis and their contacts. The antigenic similarity of the group of Bulgarian strains and their relationship with the prototype BrCr strain of E71 was established. The conclusion is that E71 was the causative agent of an outbreak of a poliomyelitis-like disease in Bulgaria.