Signs and Symptoms
Infection with Nipah virus (NiV) can cause mild to severe disease, including swelling of the brain (encephalitis) and potentially death.
Symptoms typically appear in 4-14 days following exposure to the virus. The illness initially presents as 3-14 days of fever and headache, and often includes signs of respiratory illness, such as cough, sore throat, and difficulty breathing. A phase of brain swelling (encephalitis) may follow, where symptoms can include drowsiness, disorientation, and mental confusion, which can rapidly progress to coma within 24-48 hours.
Symptoms may initially include one or several of the following:
- Fever
- Headache
- Cough
- Sore throat
- Difficulty breathing
- Vomiting
Severe symptoms may follow, such as:
- Disorientation, drowsiness, or confusion
- Seizures
- Coma
- Brain swelling (encephalitis)
Death may occur in 40-75% of cases. Long-term side effects in survivors of Nipah virus infection have been noted, including persistent convulsions and personality changes.
Infections that lead to symptoms and sometimes death much later after exposure (known as dormant or latent infections) have also been reported months and even years after exposure.