Written by Prof. Jin-Won Song
The hepatitis E virus (HEV), the etiological agent of hepatitis E, accounts for approximately 7.5% of acute hepatitis cases in South Korea. Since July 2020, a total of 1,784 cases of hepatitis E has been reported by Korea Disease Control and Prevention Agency, resulting in three fatalities. Specifically, HEV infections occurred in 191 cases in 2020, 494 cases in 2021, 528 cases in 2022, and 571 cases in 2023, respectively. Despite the recent increase in HEV cases in Korea, they are still underestimated due to the current low awareness of hepatitis E and non-standardized diagnostic methods.
In late 2022, this study began through collaboration with Prof. Ji Hoon Kim from the Department of Internal Medicine, Division of Gastroenterology and Hepatology, Korea University Guro Hospital, Korea. Prof. Ji Hoon Kim and I were deeply impressed by the hepatitis E cohort study conducted in Spain by Antonio et al and obtained important clues. Previously, it was believed that rat HEV (genus Rocahepevirus) would be unable to cause infection in humans due to its high genetic and phylogenetic differences from the species of HEV (genus Paslahepevirus) known to infect humans. However, recent studies highlight the global concern surrounding rat HEV, attracting attention for its reported human infections. Thus far, 13 clinical cases of rat HEV infection have been recorded among both immunocompetent and immunocompromised patients in various locations, including Hong Kong, Canada (with travel history to Uganda), Spain, and France (with travel history to India).
In this study, we first discovered and characterized the genomes of rat HEV (genus Rocahepevirus) from wild rats circulating in Korea. A recent study led by my lab examined 186 wild rats captured from multiple areas in Korea between 2011 and 2021. In total, 186 Norway rats (Rattus norvegicus) were collected from six cities: Seoul Metropolitan City (168/186), Jeju‐si (10/186), Osan‐si (3/186), Chuncheon‐si (1/186), Gangneung‐si (2/186), and Cheorwon‐gun (2/186), respectively. Notably, the study unveiled, for the first time in Korea, an 8 out of 180 (4.4%) prevalence of rat HEV infection in rodents residing within Seoul Metropolitan City (7 out of 164; 4.3%) and Jeju-si (1 out of 10; 10%). Six rats were not examined due to having decomposed and damaged liver tissues. No viral genome was detecetd in the rats captured from other regions, Korea in this study. Employing next-generation sequencing methodologies, we elucidated the complete-genome sequence of three rat HEV isolates derived from R. norvegicus, thereby confirming their taxonomic classification within the Rocahepevirus genus. Phylogenetic analysis demonstrated that the variants of rat HEV in Korea formed an independent genetic lineage closely related to strains from Germany, the USA, Indonesia, and China, illustrating both geographical and genetic diversity.
Prof. Ji-Hoon Kim and I emphasized the significance of the study, highlighting that the rat-derived HEV discovered in Korea belongs to the same genus as the virus recently reported in patients in Hong Kong, Spain, France, and Canada, thereby underscoring potential implications. I stressed the imperative for heightened awareness of hepatitis E and the implementation of standardized diagnostic methods, given the likelihood of a significant number of infected individuals within the community.
Read the full article published in Journal of Medical Virology, 2024 Jan;96(1):e29401. DOI: 10.1002/jmv.29401
Prof. Jin-Won Song is a Professor at the Department of Microbioloy, Korea University College of Medicine, and currntly serving as the Dean of the Graduate School at Korea University, Korea.
