title: Isolation of hepatitis E virus genotype 4 from patients with acute cryptogenic hepatitis in Korea.
abstract: Autochthonous hepatitis E occurs sporadically in developed countries. The consumption of undercooked pork containing hepatitis E virus genotype 3 (HEV-3) or 4 (HEV-4) is the major risk factor for infection. The serological diagnostic kits currently used in hospitals sometimes produce false-negative or -positive results. Therefore, detection of both HEV RNA and antibodies to the virus is required for confirmative diagnosis of hepatitis E.
  
  
  
  We aimed to detect HEV in serum samples from patients with cryptogenic hepatitis and to determine the origin of HEV.
  
  
  
  A nested polymerase chain reaction (PCR) method was developed for detection of HEV-3 and HEV-4 in patients with hepatitis. A total of 23 serum samples, deposited in 2006-2012, from patients with acute cryptogenic hepatitis who were serologically negative for hepatitis A, B, C, and E were examined using this method. The amplified PCR products were genetically analyzed.
  
  
  
  Four HEV-4 isolates were detected from the 23 serum samples. Phylogenetic analysis indicated that three of the four isolates were closely related to HEV-4 isolates found in pigs in Korea and in patients with hepatitis E in Japan.
  
  
  
  The newly developed nested PCR method was useful for detection of HEV in patients with cryptogenic hepatitis. The close relationship between the human HEV-4 isolates identified in this study and swine isolates implied that zoonotic transmission of HEV might be a source of infection in patients with hepatitis.
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, College of Medicine, Seoul National University, Seongnam, Gyeonggi 13620, Republic of Korea.
authors.forename: Sook-Hyang
authors.initials: SH
authors.lastname: Jeong
authors.affiliation: Department of Infectious Diseases, College of Veterinary Medicine, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea.
authors.forename: Byung-Joo
authors.initials: BJ
authors.lastname: Park
authors.affiliation: Department of Infectious Diseases, College of Veterinary Medicine, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea.
authors.forename: Yong-Hyun
authors.initials: YH
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, College of Medicine, Seoul National University, Seongnam, Gyeonggi 13620, Republic of Korea.
authors.forename: Yun Suk
authors.initials: YS
authors.lastname: Choi
authors.affiliation: Department of Infectious Diseases, College of Veterinary Medicine, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea.
authors.forename: Hee-Seop
authors.initials: HS
authors.lastname: Ahn
authors.affiliation: Department of Infectious Diseases, College of Veterinary Medicine, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea.
authors.forename: Sang-Hoon
authors.initials: SH
authors.lastname: Han
authors.affiliation: Department of Infectious Diseases, College of Veterinary Medicine, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea. Electronic address: ischoi@konkuk.ac.kr.
authors.forename: In-Soo
authors.initials: IS
authors.lastname: Choi
mesh_terms: D016000:Cluster Analysis; D005838:Genotype; D016751:Hepatitis E / Q000175:diagnosis* / Q000821:virology; D016752:Hepatitis E virus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D011446:Prospective Studies; D012367:RNA, Viral / Q000032:analysis / Q000235:genetics; D056910:Republic of Korea; D017422:Sequence Analysis, DNA; D044967:Serum / Q000821:virology
chemical_list: D012367:RNA, Viral
keywords: Cryptogenic; Hepatitis; Hepatitis e virus genotype 4; Korea; Pigs