Molecular epidemiology of Japanese encephalitis virus circulating in South Korea, 1983-2005

Abstract

We sequenced the envelope (E) gene of 17 strains of the Japanese encephalitis virus (JEV) isolated in South Korea in 1983-2005 and compared the sequences with those from previously reported strains. Our results show the remarkable genetic stability of the E gene sequence in Korean JEV strains. Five pairs of E gene sequences from 10 Korean strains were identical, despite geographical differences and a maximum five-year time span. Sequence comparisons with other Asian strains revealed that the Korean strains are closely related to those from China, Japan, and Vietnam. Genotype 3 strains were predominant in Korea before 1993, when genotype 1 strain K93A07 was first isolated. The two genotypes were detected simultaneously in 1994 but since then, only genotype 1 has been isolated in South Korea. Thus, the genotype change occurred according to the year of isolation rather than the geographical origin.

In vitro growth, pathogenicity and serological characteristics of the Japanese encephalitis virus genotype V Muar strain

“…However, the major genotype of JEV isolated in Japan changed from GIII to GI in the early 1990s (Ma et al, 2003;Yoshida et al, 2005). In recent years, a similar genotype shift has been observed in South Korea, northern Vietnam, China, Taiwan and Thailand Nam et al, 1996;Nga et al, 2004;Nitatpattana et al, 2008;Pan et al, 2011;Wang et al, 2007;Yang et al, 2004;Yun et al, 2010;Zhang et al, , 2011. GI JEV has also been found in India since 2009 (Fulmali et al, 2011).…”

Evaluation of Japanese encephalitis virus vaccine strains currently used in pigs by molecular characterization

“…The JEV vaccines manufactured by biologic companies in Korea have been applied to pigs for the prevention of JE epidemic in human and pigs. Developments of JEV vaccine based on the molecular biology have been reported by several scientists (Beasley et al, 2008;Hong et al, 1998;Yun et al, 2010;Zhang et al, 2011). We conducted biological methods on JEV vaccine and obtained that JEV in the vaccines was identified by specific CPE and IFA in the Vero cells, indicating that five different Korean animal vaccine companies have produced JEV vaccine without changing original seed.…”

“…JEV is a member of the Flaviviridae family and Flavivirus genus (Yun et al, 2010). RNA genome of JEV contains a single open reading frame (ORF) encoding a polyprotein approximately 11kb in length.…”

When Japanese Encephalitis Virus Invaded Eastern Hemisphere – The History of the Spread of Virus Genotypes

“…Whatever the reason is, these findings show that JE is an emerging-remerging disease which may colonize new areas, whilst trades of goods, as well as transport of people are in constant development and increase the probability of the virus to be introduced in vectors or animals. (Ma et al, 2003), South Korea (Yun et al, 2010), North East China (Wang et al, 2007a) and Central China (Wang et al, 2007a), since early 1990's. Furthermore, whereas JEV strains of genotype I were detected, none isolate was obtained from human patients before the second half of the 2000's.…”