OBJECTIVES: In this study, we demonstrated that TBEV-infected ticks have been 
distributed in the ROK, combined with our previous results. These results 
suggest that TBEV may exist in the ROK, and H. longicornis, H. flava, and I. 
nipponensis may be potential vectors of TBEV. In addition, these results 
emphasize the need for further epidemiological research of TBEV.
METHODS: We examined for the presence of RNA of TBEV by reverse 
transcriptase-nested polymerase chain reaction (RT-nested PCR) using ixodid 
ticks captured in 25 localities of 10 provinces. Ticks were collected by the 
flagging and dragging method or using sentinel BG traps at forests, grass 
thickets, and grassland. A total of 13,053 ticks belonging to two genera and 
four species were collected and pooled (1292 pools), according to collection 
site, species of tick, and developmental stage.
RESULTS: Among 1292 pools, the envelope (E) protein gene of TBEV was detected 
using RT-nested PCR in 10 pools (3 pools of the 1,331 adult ticks and 7 pools of 
the 11,169 nymph ticks) collected from Gangwon-do province, Jeonrabuk-do 
province, and Jeju Island. The minimum infection rates for TBEV of Haemaphysalis 
longicornis, Haemaphysalis flava, and Ixodes nipponensis were 0.06%, 0.17%, and 
2.38%, respectively. Phylogenetic analysis based on the partial E protein gene 
was performed to identify relationships between the TBEV strains. This showed 
that 10 Korean strains clustered with the Western subtype.
CONCLUSION: In this study, we investigated the prevalence of tick-borne 
encephalitis virus (TBEV) in ixodid ticks from various regions of the Republic 
of Korea (ROK) during 2011-2012 to identify whether TBEV is circulating and to 
determine the endemic regions of TBEV.