Nipah virus (NiV)

Nipah virus (NiV)

Nipah virus (NiV) is a zoonotic virus, meaning that it can spread between animals and people. Fruit bats, also called flying foxes, are the animal reservoir for NiV in nature. Nipah virus is also known to cause illness in pigs and people. Infection with NiV is associated with encephalitis (swelling of the brain) and can cause mild to severe illness and even death. Outbreaks occur almost annually in parts of Asia, primarily Bangladesh and India.

Nipah virus infection can be prevented by avoiding exposure to sick pigs and bats in areas where the virus is present, and not drinking raw date palm sap which can be contaminated by an infected bat. During an outbreak, standard infection control practices can help prevent person-to-person spread in hospital settings.

What is Nipah Virus?

Nipah virus (NiV) was first discovered in 1999 following an outbreak of disease in pigs and people in Malaysia and Singapore. This outbreak resulted in nearly 300 human cases and more than 100 deaths, and caused substantial economic impact as more than 1 million pigs were killed to help control the outbreak.

While there have been no other known outbreaks of NiV in Malaysia and Singapore since 1999, outbreaks have been recorded almost annually in some parts of Asia since then—primarily in Bangladesh and India. The virus has been shown to spread from person-to-person in these outbreaks, raising concerns about the potential for NiV to cause a global pandemic.

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

Signs & 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.

Prevention

In areas where Nipah virus (NiV) outbreaks have occurred people should:

• Practice handwashing regularly with soap and water

• Avoid contact with sick bats or pigs

• Avoid areas where bats are known to roost

• Avoid eating or drinking products that could be contaminated by bats, such as raw date palm sap, raw fruit, or fruit that is found on the ground

• Avoid contact with the blood or body fluids of any person known to be infected with NiV