Cases Per Year: 10 to 300
Fatality Rate: 40% to 75%
First Discovered: 1999 by Dr. Kaw Bing Chua in Malaysia
The natural reservoir of the Nipah virus is the Pteropus bat species. Nipah virus can be transmitted to humans from animals (bats or pigs) or contaminated foods or can be transmitted directly between humans.
The incubation period is typically 4 to 14 days but can last up to 45 days. Effects of Nipah virus range from asymptomatic infection to acute respiratory illness and fatal encephalitis. Symptomatic people initially develop fever, headaches, muscle pain, vomiting, and sore throat. This can be followed by dizziness, drowsiness, altered consciousness, atypical pneumonia and severe respiratory problems. Severe cases see symptoms of encephalitis and seizures, which progress to a coma within 24 to 48 hours. Approximately 20% of patients are left with residual neurological consequences such as seizure disorder, personality changes, or development of delayed onset encephalitis.
There have only been a few known outbreaks in Asia, specifically in Malaysia, Bangladesh, and India. The virus infects a wide range of animals, particularly pigs (causing significant economic loss for farmers) and can cause severe disease and death in people.
Photo: Nipah virus particle (purple) – Electron micrograph.