| frequency of amantadine-resistant influenza a virus isolated from 2001-02 to 2004-05 in nara prefecture. | we investigated the frequency of amantadine-resistant influenza a viruses in nara prefecture during four epidemic seasons from 2001-02 to 2004-05. point mutations within the m2 gene were identified using rt-pcr and dna sequencing analysis. five viruses (3.4%) with point mutation were observed from 145 strains analyzed. three viruses (2.0%) possessed a change at position 31 (agt-->aat, ser to asn), one virus (0.7%) showed a change at position 26 (ctt-->ttt, leu to phe), one virus (0.7%) showed a ... | 2006 | 16785705 |