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Published on: December 29, 2015
Japanese Encephalitis Virus Genotypes 1 and 3 Isolation in Kochi, Japan
Kiyohiko Matsui1,2,3, Miyuki Yamaya4, Mina Takase4
1Department of Medical Technology, School of Life and Environmental Science, Azabu University, Japan.
Abstract:
Japanese encephalitis virus (JEV) is a mosquito-borne virus belonging to the JEV serocomplex within the genus Flavivirus, family Flaviviridae. It has 5 genotypes, G1-G5, based on the envelope (E) protein nucleotide sequence. JEV G3 circulated in Japan until the early 1990s when it was replaced by G1. JEV G3 was isolated from swine serum samples (sw/Kochi/1/2004) in the Kochi Prefecture, western Japan, in 2004. In addition, the 2018 isolates from pigs and cows (sw/Kochi/492/2018 and bo/Kochi/211/2018) in the same prefecture were identified as G3. The nucleotide sequencing results of the sw/Kochi/492/2018 and bo/Kochi/211/2018 polyprotein region differed from those of the sw/Kochi/1/2004 strain described in our previous report. Seven JEV isolates were identified as G1 in the same geographical area as that in this study. This result indicates that both JEV G1 and G3 are present in the Kochi area.
Insights
Japanese encephalitis virus (JEV) genotype 3 (G3) has re-emerged in Japan's Kochi Prefecture. Both JEV G1 and G3 strains are now co-circulating in the region, indicating a significant shift in viral activity.
Area of Science:
- Virology
- Molecular Biology
- Epidemiology
Background:
- Japanese encephalitis virus (JEV) is a significant mosquito-borne flavivirus responsible for encephalitis in humans.
- JEV is classified into five genotypes (G1-G5) based on envelope (E) protein sequences.
- Genotype G1 replaced G3 in Japan in the early 1990s.
Purpose of the Study:
- To investigate the current genotypes of Japanese encephalitis virus circulating in Kochi Prefecture, Japan.
- To analyze genetic differences between recent JEV G3 isolates and previously reported strains.
Main Methods:
- Nucleotide sequencing of the polyprotein region of JEV isolates from swine and bovine samples.
- Comparison of sequencing results with existing JEV genotype databases.
Main Results:
- JEV genotype G3 was isolated from swine and bovine samples in Kochi Prefecture in 2018.
- Genetic analysis revealed differences between the 2018 G3 isolates and a previously identified 2004 G3 strain.
- Seven JEV G1 isolates were also detected in the same geographical area.
Conclusions:
- Both JEV genotypes G1 and G3 are currently co-circulating in the Kochi area.
- The re-emergence of JEV G3 suggests a dynamic evolution and circulation pattern of the virus in Japan.
