Characterization of a wild poliovirus type 3 isolated Japan in 1993.

A wild poliovirus type 3 was isolated from a throat swab of a patient with upper respiratory symptoms without paralysis in Shiga Prefecture, in 1993. Wild poliovirus has never been isolated in these nine years in Japan. The most recent isolation of wild poliovirus was of type 1 in 1984 from a case of encephalomyelitis in Aichi Prefecture. Antigenic and PCR-restriction fragment length polymorphism analyses revealed that the Shiga strain was non-Sabin origin. Sequence analysis of the VP1 region confirmed that the isolate was a wild poliovirus type 3. Furthermore, this isolate had higher homology to the isolates from North Vietnam than those from Pakistan or Finland, suggesting that the Shiga strain was imported from Asian area. This strain was also shown to be neurovilurent in transgenic mice carrying human poliovirus receptor gene.