title: Japanese encephalitis in a 114-month-old cow: pathological investigation of the affected cow and genetic characterization of Japanese encephalitis virus isolate.
abstract: BACKGROUND
  Japanese encephalitis virus (JEV) is classified into the genus Flavivirus in the family Flaviviridae. JEV can cause febrile illness and encephalitis mainly in humans and horses, and occasionally in cattle.
  
  
  METHODS
  In late September 2010, a 114-month-old cow showed neurological symptoms similar to the symptoms observed in previous bovine cases of Japanese encephalitis (JE); therefore, we conducted virological and pathological tests on the cow. As a result, JEV was isolated from the cerebrum of the affected cow. We determined the complete genome sequence of the JEV isolate, which we named JEV/Bo/Aichi/1/2010, including the envelope (E) gene region and 3' untranslated region (3'UTR). Our phylogenetic analyses of the E region and complete genome showed that the isolate belongs to JEV genotype 1 (G1). The isolate, JEV/Bo/Aichi/1/2010, was most closely related to several JEV G1 isolates in Toyama Prefecture, Japan in 2007-2009 by the phylogenetic analysis of the E region. In addition, the nucleotide alignment revealed that the deletion in the 3'UTR was the same between JEV/Bo/Aichi/1/2010 and several other JEV G1 isolates identified in Toyama Prefecture in 2008-2009. A hemagglutination inhibition (HI) test was conducted for the detection of anti-JEV antibodies in the affected cow, and the test detected 2-mercaptoethanol (2-ME)-sensitive HI antibodies against JEV in the serum of the affected cow. The histopathological investigation revealed nonsuppurative encephalomyelitis in the affected cow, and the immunohistochemical assay detected JEV antigen in the cerebrum.
  
  
  CONCLUSIONS
  We diagnosed the case as JE of a cow based on the findings of nonsuppurative encephalomyelitis observed in the central nervous system, JEV antigen detected in the cerebrum, JEV isolated from the cerebrum, and 2-ME-sensitive HI antibodies against JEV detected in the serum. This is the first reported case of JE in a cow over 24 months old.
authors.forename: Naomi
authors.initials: N
authors.lastname: Kako
authors.forename: Seiji
authors.initials: S
authors.lastname: Suzuki
authors.forename: Norie
authors.initials: N
authors.lastname: Sugie
authors.forename: Tomoko
authors.initials: T
authors.lastname: Kato
authors.forename: Tohru
authors.initials: T
authors.lastname: Yanase
authors.forename: Makoto
authors.initials: M
authors.lastname: Yamakawa
authors.affiliation: Subtropical Diseases Research Division, National Institute of Animal Health (NIAH), National Agriculture and Food Research Organization (NARO), 2702 Chuzan, Kagoshima 891-0105, Japan. shirah@affrc.go.jp.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Shirafuji
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D002417:Cattle; D002418:Cattle Diseases / Q000821:virology*; D004664:Encephalitis Virus, Japanese / Q000235:genetics*; D004672:Encephalitis, Japanese / Q000097:blood / Q000662:veterinary* / Q000821:virology; D005260:Female; D010802:Phylogeny; D016036:Seroepidemiologic Studies
chemical_list: D000914:Antibodies, Viral