Hantaan virus possesses a three-segmented, single-stranded RNA genome of negative polarity. The large(L), medium(M), and small(S) genome segments encode polymerase, envelope glycoprotein, and nucleocapsid protein, respectively. The 76-118 strain,
prototype hantaan virus, was isolated from lung tissue of Apodemus agrarius caught in 1976 and the M segment was sequenced in 1986. From April to May in 1994, fourty five Apodemus agrarius were caught at Songnneri that was the place 76-118 strain
of
hantaan virus was isolated originally, and the sera were screened by IFA method against hantaan virus. Hantaan viral RNAs from three IFA positive(6.7%) Apodemus lungs were extracted and nested RT-PCR was done with four oligonucleotides flanking
5'-G2
coding region. DNA sequences of 331bp spanning region were determined by cycle sequencing method and those sequences from three IFA-positive were identical and showed two nucleotide changes(0.6%) at positions 2294 and 2296 compared to sequence of
76-118
strain. Base substitution at position 2296 was silent, but substitution at position 2294 occurred at codon position 1 and resulted in amino acid alteration(His→Tyr). Assuming constant rate of divergence, the mutation rate of hantaan virus in
natural
condition is 1.68×10E-4-3.36×10E-4 substitutions/nucleotide/year.
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