Genetic Characterization of Japanese Encephalitis Virus Genotype 5 Isolated from Patient, South Korea, 2015

Area of Science:

• Virology
• Molecular Biology
• Public Health

Background:

• Japanese encephalitis virus (JEV) is a significant cause of viral encephalitis in Asia.
• Understanding the genetic diversity and evolution of JEV is crucial for disease control and prevention.
• Previous studies have identified various genotypes of JEV, with ongoing surveillance needed to detect emerging strains.

Purpose of the Study:

• To report the isolation and characterization of a novel Japanese encephalitis virus genotype 5 strain from human samples in South Korea.
• To perform whole-genome analysis to understand the genetic relatedness and unique features of this new strain.
• To identify specific genetic markers that distinguish this South Korean JEV genotype 5 from other known strains.

Main Methods:

• Isolation of Japanese encephalitis virus from human clinical specimens.
• Whole-genome sequencing and phylogenetic analysis of the isolated virus.
• Comparative genomic analysis to identify unique genetic mutations and insertions, focusing on the NS4A gene and envelope protein.

Main Results:

• Successful isolation of Japanese encephalitis virus genotype 5 from human specimens in South Korea.
• Whole-genome sequencing revealed approximately 90.4% nucleotide identity with other known genotype 5 JEV strains.
• Identification of a unique insertion within the NS4A gene and a specific Lysine at position 84 in the envelope protein, characteristic of South Korean genotype 5 strains.

Conclusions:

• The findings confirm the circulation of Japanese encephalitis virus genotype 5 in South Korea, originating from human infections.
• The identified unique genetic features, particularly in the NS4A gene and envelope protein, highlight the distinct evolutionary path of this South Korean JEV strain.
• This discovery underscores the importance of continuous genomic surveillance for JEV to monitor viral evolution and potential public health implications.