What is Nipah Virus?
Nippah virus (NiV) was detected in 1999 in Malaysia and Singapore pigs and people. About 300 human cases, and over 100 deaths. And had considerable economic impact, as more than 1 million pigs were killed to control and prevent the spread of the virus. The virus is spreading in parts of Bangladesh and India other than Malaysia and Singapore.
NiV is a member of the family Paramyxoviridae, genus Henipavirus. It is a zoonotic virus, meaning that it initially spreads between animals and people. henipavirus known to be carried by bats, bat species were quickly singled out for investigation and flying foxes were subsequently identified as the reservoir.
Infected fruit bats can spread the disease to people or other animals, such as pigs. People can become infected if they have close contact with an infected animal or its body fluids (such as saliva or urine)—this initial spread from an animal to a person is known as a spillover event. Once it spreads to people, person-to-person spread of NiV can also occur.
The symptoms of NiV infection range from mild to severe, with death occurring in 40%–70% of those infected in documented outbreaks between 1998 and 2018.
Transmission
Nipah virus (NiV) can spread to people from:
- Close contact with a person infected with NiV or their body fluids (including nasal or respiratory droplets, urine, or blood)
- Direct contact with infected animals, such as bats or pigs, or their body fluids (such as blood, urine or saliva)
- Consuming food products that have been contaminated by body fluids of infected animals (such as palm sap or fruit contaminated by an infected bat)
The NiV strain transmitted initially from bats to pigs, with subsequent spread within pig populations. Then people who worked closely with infected pigs began falling ill. No person-to-person transmission was reported initially.
However, person-to-person spread of NiV is regularly reported in Bangladesh and India. This is most commonly seen in the families and caregivers of NiV-infected patients, and in healthcare settings. Transmission also occurs from exposure to food products that have been contaminated by infected animals, including consumption of raw date palm sap or fruit that has been contaminated with saliva or urine from infected bats. Some cases of NiV infection have also been reported among people who climb trees where bats often roost.
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.
Diagnosis
During early stages of the illness, laboratory testing can be conducted using real time polymerase chain reaction (RT-PCR) from throat and nasal swabs, cerebrospinal fluid, urine, and blood. Later in the course of illness and after recovery, testing for antibodies is conducted using an enzyme-linked immunosorbent assay (ELISA).
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.
Prevention
- Practice handwashing regularly with soap and water
- Avoid contact with sick bats or pigs
- Avoid areas where bats are known to roost
- Avoid consumption of raw date palm sap
- Avoid consumption of fruits that may be contaminated by bats
- Avoid contact with the blood or body fluids of any person known to be infected with NiV
Because NiV can be spread from person-to-person, standard infection control practices and proper barrier nursing techniques are important in preventing hospital-acquired infections (nosocomial transmission) in settings where a patient has confirmed or suspected NiV infection.
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