Overview
Nipah is a zoonotic virus and a member of the family Paramyxoviridae, genus Henipavirus. A type of fruit bat commonly known as a flying fox (genus Pteropus) can carry the virus and transmit it to people or animals, particularly pigs. This bat can be found throughout Southeast Asia, the South Pacific, and Australia region, but Nipah outbreaks have only been reported in Bangladesh, India, Malaysia, Philippines, and Singapore.
Human infection can occur if they have close contact with an infected animal or its body fluids, potentially followed by person-to-person transmission.
Exposure risks
People with an increased risk for Nipah include:
- People who work closely with pigs
- Families and caregivers of people with Nipah
- Healthcare workers caring for patients with Nipah
- People exposed to food or drinks contaminated by infected animals, particularly raw date palm sap
- People who climb trees where infected bats often roost
Signs and symptoms
Symptoms typically appear 4-14 days following exposure to the virus. Dormant or latent infections have been reported months and even years after exposure.
People with Nipah are usually sick for 3-14 days. Initial symptoms may include:
- Fever
- Headache
- Cough
- Sore throat
- Difficulty breathing
- Vomiting
Later in the course of infection, patients may experience:
- Disorientation, drowsiness, or confusion
- Seizures
- Coma, possibly within 24 to 48 hours after symptom onset
The case-fatality rate for Nipah virus infection ranges from 45-70%.
Prevention
If Nipah is suspected and the patient is clinically stable:
Healthcare providers should wear gown, gloves, eye protection, and a N95 respirator or higher.
If Nipah is suspected and the patient is clinically unstable OR Nipah is confirmed regardless of clinical stability:
Healthcare providers should use personal protective equipment according to clinically unstable VHF guidance.
Testing and diagnosis
Diagnosing Nipah virus infection can be challenging due to its non-specific early symptoms. However, early detection is critical to improve chance of survival, prevent transmission, and contain an outbreak. Consider Nipah in people with relevant symptoms who have been in areas where the virus is endemic.
Testing for Nipah virus infection can take place during illness or after recovery. During early stages of infection, test for Nipah virus using real time polymerase chain reaction (RT-PCR) from throat and nasal swabs, cerebrospinal fluid, urine, or blood. Later in the course of illness or after recovery, test for antibodies using an enzyme-linked immunosorbent assay (ELISA).
Treatment and recovery
Currently there are no licensed treatments available for Nipah. Treatment is limited to supportive care, including rest, hydration, and symptom management.
While there is no licensed treatment, there are several treatment options in development:
- Several experimental monoclonal antibodies are in development.
- The drug remdesivir has helped prevent Nipah when given to exposed nonhuman primates.
- Remdesivir may be used in combination with immunotherapeutic treatments such as certain monoclonal antibodies.
- Ribavirin was used to treat a small number of patients in the 1999 Malaysian Nipah outbreak, but its efficacy is unclear.
Long-term effects
Survivors of Nipah virus infection often experience long-term effects including persistent convulsions and personality changes.
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