Re-emergence Nipah - a review

There was an outbreak of new emergence viral encephalitis caused by Nipah virus among humans in some areas of Bangladesh during 2001 - till to date. The disease affected mainly the young, had increased suspicion to spread from bat to man through eating of the same fruits. The risk of human-to-human transmission is thought to be low though many of the affected individuals belonged to the same family. The disease presented mainly as acute encephalitis with usually a short incubation period of less than two weeks, with the main symptoms of fever, headache, and giddiness followed by coma. Distinctive clinical signs include areflexia, hypotonia, hypertension, tachycardia and segmental myoclonus. Serology was helpful in confirming the diagnosis. Magnetic resonance imaging (MRI) showed distinctive changes of multiple, discrete or confluent small high signal lesions, best seen with fluid-attenuated inversion recovery (FLAIR) sequences. Mortality was as high as 32-92% and death was probably due to severe brainstem involvement. Relapse encephalitis was seen in those who recovered from acute encephalitis, and late-onset encephalitis was seen in those with initial non-encephalitic or asymptomatic diseases. Both these manifested as focal encephalitis arising from recurrent infection.