Isolation and identification of monkeypox virus MPXV-ROK-P1-2022 from the first case in the Republic of Korea

OBJECTIVES: Monkeypox outbreaks in nonendemic countries have been reported since early May 2022. The first case of monkeypox in the Republic of Korea was confirmed in a patient who traveled to Europe in June 2022, and an attempt was made to isolate and identify the monkeypox virus (MPXV) from the patient’s specimens. METHODS: Clinical specimens from the patient were inoculated in Vero E6 cells. The isolated virus was identified as MPXV by the observation of cytopathic effects on Vero E6 cells, transmission electron microscopy, conventional polymerase chain reaction (PCR), and sequencing of PCR products. RESULTS: Cytopathic effects were observed in Vero E6 cells that were inoculated with skin lesion swab eluates. After multiple passages from the primary culture, orthopoxvirus morphology was observed using transmission electron microscopy. In addition, both MPXV-specific (F3L and ATI) and orthopoxvirus-specific genes (A39R, B2R, and HA) were confirmed by conventional PCR and Sanger sequencing. CONCLUSION: These results indicate the successful isolation and identification of MPXV from the first patient in the Republic of Korea. The isolated virus was named MPXV-ROK-P1-2022.