title: Enterovirus 71 encephalomyelitis and Japanese encephalitis can be distinguished by topographic distribution of inflammation and specific intraneuronal detection of viral antigen and RNA.
abstract: OBJECTIVE
  To investigate if two important epidemic viral encephalitis in children, Enterovirus 71 (EV71) encephalomyelitis and Japanese encephalitis (JE) whose clinical and pathological features may be nonspecific and overlapping, could be distinguished.
  
  
  METHODS
  Tissue sections from the central nervous system of infected cases were examined by light microscopy, immunohistochemistry and in situ hybridization.
  
  
  RESULTS
  All 13 cases of EV71 encephalomyelitis collected from Asia and France invariably showed stereotyped distribution of inflammation in the spinal cord, brainstem, hypothalamus, cerebellar dentate nucleus and, to a lesser extent, cerebral cortex and meninges. Anterior pons, corpus striatum, thalamus, temporal lobe, hippocampus and cerebellar cortex were always uninflamed. In contrast, the eight JE cases studied showed inflammation involving most neuronal areas of the central nervous system, including the areas that were uninflamed in EV71 encephalomyelitis. Lesions in both infections were nonspecific, consisting of perivascular and parenchymal infiltration by inflammatory cells, oedematous/necrolytic areas, microglial nodules and neuronophagia. Viral inclusions were absent.
  
  
  CONCLUSIONS
  Immunohistochemistry and in situ hybridization assays were useful to identify the causative virus, localizing viral antigens and RNA, respectively, almost exclusively to neurones. The stereotyped distribution of inflammatory lesions in EV71 encephalomyelitis appears to be very useful to help distinguish it from JE.
authors.affiliation: Faculty of Medicine, University of Malaya, Kuala Lumpur, Kuching, Malaysia. wongkt@ummc.edu.my
authors.forename: K T
authors.initials: KT
authors.lastname: Wong
authors.forename: K Y
authors.initials: KY
authors.lastname: Ng
authors.forename: K C
authors.initials: KC
authors.lastname: Ong
authors.forename: W F
authors.initials: WF
authors.lastname: Ng
authors.forename: S K
authors.initials: SK
authors.lastname: Shankar
authors.forename: A
authors.initials: A
authors.lastname: Mahadevan
authors.forename: B
authors.initials: B
authors.lastname: Radotra
authors.forename: I J
authors.initials: IJ
authors.lastname: Su
authors.forename: G
authors.initials: G
authors.lastname: Lau
authors.forename: A E
authors.initials: AE
authors.lastname: Ling
authors.forename: K P
authors.initials: KP
authors.lastname: Chan
authors.forename: P
authors.initials: P
authors.lastname: Macorelles
authors.forename: S
authors.initials: S
authors.lastname: Vallet
authors.forename: M J
authors.initials: MJ
authors.lastname: Cardosa
authors.forename: A
authors.initials: A
authors.lastname: Desai
authors.forename: V
authors.initials: V
authors.lastname: Ravi
authors.forename: N
authors.initials: N
authors.lastname: Nagata
authors.forename: H
authors.initials: H
authors.lastname: Shimizu
authors.forename: T
authors.initials: T
authors.lastname: Takasaki
mesh_terms: D000293:Adolescent; D000956:Antigens, Viral / Q000032:analysis*; D001208:Asia; D002490:Central Nervous System / Q000473:pathology* / Q000821:virology; D002648:Child; D002675:Child, Preschool; D004672:Encephalitis, Japanese / Q000473:pathology* / Q000821:virology; D029821:Enterovirus A, Human / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D004769:Enterovirus Infections / Q000473:pathology* / Q000821:virology; D005260:Female; D005602:France; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D012367:RNA, Viral / Q000032:analysis*; D055815:Young Adult
chemical_list: D000956:Antigens, Viral; D012367:RNA, Viral