IDENTIFICATION OF ENTEROVIRUS 71 BY NEUTRALIZATION AND RT-PCR IN KOREA DURING 2000

Doo-Sung Cheon¹, Gwang-Cheon Jang², Dong-Soo Kim³, Eui-Chong Kim⁴

¹ Department of Virology, National Institute of Health, Seoul, Korea

^{2, 3} Yonsei University College of Medicine, Seoul, Republic of Korea

⁴ Seoul National University College of Medicine, Seoul, Korea

Objective: Enterovirus 71 (EV 71) was first isolation from severe neurologic disease between 1969 and 1973 in California. Clinical features were hand, foot and mouse disease (HFMD), herpangina, aseptic meningitis, acute flaccid paralysis, and fatal encephalitis. Outbreaks were accompanying with high fatality and neurological complications in Bulgaria (1975), Hungary (1978), Malaysia (1997), and Taiwan (1998).

Methods: Enteroviruses 71 were isolated in cerebro spinal fluid (CSF) and stool of 13 patients showing HFMD or herpangina or acute flaccid paralysis. Routine processing and inoculation to Vero cell and Rd cell did virus isolation. RT-PCR primers were designed from conserved parts of the VP1 and VP4 gene of EV 71 strains. Immunofluorescence assay was used by monoclonal antibody to react with EV 71 specifically. Virus neutralization assays were use of rabbit anti-EV 71 antiserum.

Results: RT-PCR with these primers showed over 98% homologies among the known isolates. Phylogenetic analysis of the RT-PCR products of 13 EV 71 strains revealed a distinct cluster with three major serotyping, thus enabling genetic typing of the viruses. Korean isolates belong to genotype C1 of EV 71.

Conclusion: EV71 was first isolated in Korea in 2000. By the sequence comparison and phylogenetic analysis, there are only minute differences among the Korean isolates. EV 71 strains of Korea were from the same or similar origin. Identification of Korean EV 71 isolates and setting up EV 71 gene bank by cooperation with laboratories in other countries are needed.

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