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.
Treatment
Currently there are no licensed treatments available for Nipah virus (NiV) infection. Treatment is limited to supportive care, including rest, hydration, and treatment of symptoms as they occur.
There are, however, immunotherapeutic treatments (monoclonal antibody therapies) that are currently under development and evaluation for treatment of NiV infections. One such monoclonal antibody, m102.4, has completed phase 1 clinical trials and has been used on a compassionate use basis. In addition, the antiviral treatment remdesivir has been effective in nonhuman primates when given as post-exposure prophylaxis, and may be complementary to immunotherapeutic treatments. The drug ribavirin was used to treat a small number of patients in the initial Malaysian NiV outbreak, but its efficacy in people is unclear.