Relapsed and late-onset Nipah encephalitis

Ann Neurol. 2002 Jun;51(6):703-8. doi: 10.1002/ana.10212.


An outbreak of infection with the Nipah virus, a novel paramyxovirus, occurred among pig farmers between September 1998 and June 1999 in Malaysia, involving 265 patients with 105 fatalities. This is a follow-up study 24 months after the outbreak. Twelve survivors (7.5%) of acute encephalitis had recurrent neurological disease (relapsed encephalitis). Of those who initially had acute nonencephalitic or asymptomatic infection, 10 patients (3.4%) had late-onset encephalitis. The mean interval between the first neurological episode and the time of initial infection was 8.4 months. Three patients had a second neurological episode. The onset of the relapsed or late-onset encephalitis was usually acute. Common clinical features were fever, headache, seizures, and focal neurological signs. Four of the 22 relapsed and late-onset encephalitis patients (18%) died. Magnetic resonance imaging typically showed patchy areas of confluent cortical lesions. Serial single-photon emission computed tomography showed the evolution of focal hyperperfusion to hypoperfusion in the corresponding areas. Necropsy of 2 patients showed changes of focal encephalitis with positive immunolocalization for Nipah virus antigens but no evidence of perivenous demyelination. We concluded that a unique relapsing and remitting encephalitis or late-onset encephalitis may result as a complication of persistent Nipah virus infection in the central nervous system.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Brain / pathology
  • Child
  • Electroencephalography
  • Encephalitis, Viral / pathology
  • Encephalitis, Viral / physiopathology*
  • Encephalitis, Viral / prevention & control
  • Female
  • Follow-Up Studies
  • Humans
  • Magnetic Resonance Imaging
  • Malaysia
  • Male
  • Middle Aged
  • Paramyxoviridae Infections / pathology
  • Paramyxoviridae Infections / physiopathology*
  • Paramyxoviridae Infections / prevention & control
  • Paramyxovirinae*
  • Recurrence
  • Time Factors
  • Tomography, Emission-Computed, Single-Photon