Nipah Virus Encephalitis

– A member of Paramyxoviridae, genus Henipavirus
– Name taken from Sungai Nipah, Seremban (where the virus is first isolated)

Epidemiology
– Southeast asia
– Pig farms (from infected pig)

  • From fruit eating bats (reservoir) -> the pigs eat the partially eaten fruits left over by the infected bats
  • Bat -> pig -> human -> human
  • Other encephalitis related to pig (vector: Culex mosquito) is Japanese encephalitis virus

Clinical features
– Flu like prodromal syndrome –> encephalitis

  • Most have brainstem signs (abnormal VOR, pinpoint pupil)
  • Seizures are also common

Lab test
– FBC: 40% will see leukopenia, thrombocytopenia and elevated transaminases (similar to dengue)
– The longer the disease goes, the more likely the antibodies will be positive

  • At day 12, anti-Nipah IgM has sensitivity of 100%
  • At day 24, anti-Nipah IgG has sens of 100%

– EEG will be abnormal

MRI imaging
– MRI

  • Nipah virus: multiple discrete hyperintense lesions in white matter, seen best in FLAIR
    Image
  • This differentiates from JE virus which may have similar clinical presentation -> hyperintense lesions (hemorrhagic) in bilateral thalami

– Pathologically, heart, kidney and lungs are affected but the brain is the most severely affected organs.
Long term outcome
– Patients will have residual neurological sequela

Tx
– Supportive only
– Ribavirin maybe okay, but need larger studies

Relapsed or delayed (late onset)
– Same disease, but different in being in delayed encephalitis the initial infection is not severe enough to cause severe neurological symotis

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