Nipah virus infection

Notification requirements for Nipah virus infection

While Nipah virus infection is not a notifiable condition in Victoria, any suspected or confirmed cases should be reported to the Department of Health immediately by calling 1300 651 160 (24/7) and connecting to the relevant Local Public Health Unit.

Infectious agent of Nipah virus infection

Nipah virus is a member of the family Paramyxoviridae, genus Henipavirus. It is a zoonotic virus which means it is usually transmitted from animals to people.

It is closely related to Hendra virus that can causes respiratory and neurological illness in horses and humans.

Identification of Nipah virus infection

Clinical features

Nipah virus infection can vary from a mild flu-like illness to severe respiratory illness or encephalitis. Some people may have no symptoms.

Initial symptoms and signs may include:

• fever
• headaches
• muscle aches and pain
• fatigue
• sore throat
• cough
• vomiting
• shortness of breath.

Some people can develop atypical pneumonia and severe respiratory problems, including acute respiratory distress syndrome.

In severe cases, people can develop encephalitis with symptoms and signs that may include:

• dizziness
• neck stiffness
• photophobia
• confusion
• drowsiness
• seizures
• altered consciousness or coma.

The case fatality rate for Nipah virus infection is estimated at 40 to 75 per cent.

Approximately 20 per cent of people who recover from encephalitis are left with residual neurological deficits. A small number of people, usually those with mild or sub-clinical cases, can relapse or develop delayed-onset encephalitis.

Diagnosis

The risk of Nipah virus infection being detected in Australia is very low. Medical practitioners are advised to assess whether their patient has a compatible clinical illness and epidemiological risk factors for Nipah virus infection. Clinicians should seek testing advice from an infectious diseases specialist and/or Local Public Health Unit. Testing must be approved by the Local Public Health Unit.

In Victoria, testing is available through the Victorian Infectious Diseases Reference Laboratory (VIDRL). Diagnosis is usually confirmed by real time polymerase chain reaction (RT-PCR) testing of specimens such as nose and throat swab, respiratory samples (sputum/bronchoscopy), EDTA blood, urine or cerebrospinal fluid.

Incubation period of Nipah virus

The incubation period is usually 4 to 14 days, but rarely can be up to 45 days.

Public health significance and occurrence of Nipah virus infection

Nipah virus was first identified during an outbreak among pig farmers and pigs in Kampung Sungai Nipah, Malaysia in 1998. Human cases and outbreaks have only ever been reported in South and South-East Asian countries of Bangladesh, India, Malaysia, Philippines, and Singapore. Nipah virus has never been detected in Australia.

No new outbreaks have been reported in recent years in Malaysia, Philippines, and Singapore. However, since 2001, outbreaks have been reported almost every year in Bangladesh, and periodically in parts of India, with several outbreaks in Kerala since 2018 and an outbreak in West Bengal in December 2025

The risk of Nipah virus infection being detected in Australia is very low. The Department of Health closely monitors for zoonotic disease outbreaks worldwide through our collaboration with national and international human and animal health organisations.

Reservoir of Nipah virus

Fruit bats from the Pteropodidae family are considered the natural host for Nipah virus. Infection does not appear to cause illness in fruit bats.

Outbreaks have been reported in other animals, with pigs being particularly susceptible to infection. Infections in these animals can result in severe disease.

Mode of transmission of Nipah virus

Transmission of Nipah virus occurs through:

• contact with infected animals, especially fruit bats and pigs, or their bodily fluids including saliva, urine or faeces
• eating fruit or fruit products, such as raw date palm juice or sap, contaminated by infected fruit bats
• direct contact with an infected person’s respiratory secretions or bodily fluids.

Person-to-person transmission is rare but has been reported through close, prolonged contact with an infected person, such as when a healthcare worker or caregiver is caring for someone who is sick with Nipah virus infection.

Period of communicability of Nipah virus infection

Unknown.

Susceptibility and resistance to Nipah virus infection

People who live in or travel to areas where Nipah virus is being detected are at increased risk of exposure and infection, particularly if they:

• work with or have contact with potentially infected animals, especially fruit bats or pigs, and their habitats
• are exposed to potentially contaminated fruit or fruit products
• are a healthcare worker or caregiver providing care to an infected person.

Control measures for Nipah virus infection

Preventative measures

There is no vaccine available to protect against Nipah virus infection.

People travelling overseas are advised to check travel advice and notices prior to travel on Smartraveller.

Measures to reduce the risk of exposure when travelling to areas where Nipah virus is being detected include the following:

• avoid contact with animals, especially fruit bats and pigs
• do not eat fruit that might have been in contact with an animal or their bodily fluids – clean and peel fruit yourself before eating it
• do not drink raw or fermented date palm juice or sap as this may have been contaminated by fruit bats
• practice good hand washing, especially after touching animals, visiting people who are sick or being out in public places
• avoid contact with anybody who is unwell and their bodily fluids.

To reduce the risk of animal-to-human and person-to-person transmission, appropriate personal protective equipment should be worn such as gloves, gowns, protective eyewear, boots (for animal exposures) and masks when in contact with potentially infected or infected animals or people, and their bodily fluids.

Good hand washing and hygiene practices should also be maintained.

Control of case

There is currently no specific treatment available to cure or treat Nipah virus infection. Treatment is supportive and aimed at managing symptoms and complications. Medical practitioners should seek treatment advice from an infectious diseases specialist.

Although Nipah virus is not currently considered to be airborne, cases should be isolated and managed in a negative pressure room (where available) under standard, contact, droplet and airborne precautions.

Healthcare staff involved in care of the case are recommended to use personal protective equipment including disposable gloves, fluid resistant long-sleeved gown, protective eyewear such as goggles or face shield, and fit-tested respirator such as P2/N95 respirator mask.

Control of contacts

Contacts are provided education about Nipah virus and advised to monitor for symptoms and signs of infection.

Contacts who develop symptoms should be assessed and tested, in consultation with an infectious diseases specialist and Local Public Health Unit.

Control of environment

Nipah virus has never been detected in Australia.

If an animal is suspected of having Nipah virus infection, report it immediately to the Department of Energy, Environment and Climate Action’s Emergency Animal Disease Hotline by calling 1800 675 888 (24/7).

Outbreak measures for Nipah virus infection

A single confirmed case of Nipah virus infection would be considered an outbreak.

Case(s) would be investigated to determine the likely source of infection through a detailed history of their work and movements. Further cases may be identified through active case finding among close contacts with similar exposure.

If a case is linked to an exposure in Victoria or elsewhere in Australia, the Department of Health will work closely with relevant animal and human health authorities and scientists to identify and control possible sources of infection.

Measures could include:

• testing possible animal sources and/or affected animals
• using appropriate personal protective equipment and hygiene practices for animal handlers and investigators on implicated farms or properties
• slaughtering infected animals and burying or incinerating the carcasses
• restricting the movement of animals from infected farms or designated areas.