What is Nipah virus?
Nipah virus is a rare but potentially life-threatening infection that can cause severe illness affecting the brain and lungs. The case fatality rate is estimated at 40 to 75 percent as reported by the World Health Organization.
The virus originates in animals, particularly fruit bats, and spreads to people through contact with infected animals or contaminated food. Fruit bats of the Pteropodidae family are the natural host of Nipah virus. Nipah virus usually transmits from infected bats and other animals to humans, and can also be transmitted directly between people.
Nipah virus has never been detected in animals or people in Australia, but outbreaks have been reported in Bangladesh, India, Malaysia, Philippines, and Singapore. Person-to-person spread is uncommon in everyday settings, but has occurred in healthcare facilities and among family members providing close care to sick people. Refer to the Australian Centre for Disease Control before travel for international outbreak updates and safety recommendations.
FAQs
Which parts of the world have had Nipah virus outbreaks?
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Nipah virus causes disease that can spread between animals and people, and outbreaks have only been reported from Bangladesh, India, Malaysia, Philippines, and Singapore.
Fruit bats capable of carrying Nipah virus are found across much of Asia, Australia, and the Pacific. However, human infections have only been reported in a small number of countries. Before travelling to affected regions, check the latest health advice.
How does Nipah virus spread to people?
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Transmission of the virus to humans can occur from direct contact with infected animals like bats, pigs or horses, and by consuming fruits or fruit products, such as raw date palm juice, contaminated by infected fruit bats. In Bangladesh in particular, drinking raw date palm sap, which bats can contaminate with their urine or saliva during the harvesting season between December and May, is a well-documented route of infection.
The virus can also cause severe disease in farming animals such as pigs, and Nipah virus can sometimes rarely spread between people. It has been reported in healthcare settings and among family and caregivers of sick people through close contact. Casual contact in airports, markets, or public spaces is not considered a significant risk.
What simple steps can I take to protect myself when travelling?
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There is no vaccine available for Nipah virus, so protection relies entirely on avoiding contact with the virus in the first place.
If you are going to an area where Nipah virus has been detected, you should avoid contact with animals, especially fruit bats and pigs, and areas where bats live. Do not eat fruit that might have been in contact with an animal or their bodily fluids, and 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. Wash your hands regularly with soap and water, particularly before eating and after spending time outdoors.
If you are visiting or caring for someone who is unwell in an affected area, avoid close unprotected contact and follow any hygiene advice provided by local health authorities.
If I feel unwell after returning from India or Bangladesh, what should I do?
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If you develop symptoms of Nipah virus infection after returning from a country where Nipah virus is detected, you should seek urgent medical care.
The most important first step is to call ahead before going to a clinic or hospital. Let the medical team know where you have been, what you may have been exposed to, and what symptoms you are experiencing. This allows staff to put appropriate precautions in place before you arrive, protecting both other patients and healthcare workers.
When you speak with a doctor, provide a full travel history covering every country you visited, the dates of your travel, and any specific exposures such as contact with bats or pigs, visits to farms or markets, or consumption of local fruit or juice. Early notification makes an enormous difference to both the care you receive and the ability of public health authorities to respond quickly if needed.
What happens if there is a Nipah virus case in Australia?
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Nipah virus is a Listed Human Disease under Australia's Biosecurity Act 2015, meaning that if a case is suspected, specific public health powers can be activated immediately. Any suspected case must be notified to the local public health unit straightaway, and the patient will be placed in appropriate isolation for assessment and testing.
There has never been a confirmed case of Nipah virus infection in Australia, but the notification framework exists precisely to make sure the response is rapid if a case ever is identified.
What to Know
Nipah virus symptoms
The time from Nipah virus infection to the onset of symptoms, ranges from three to fourteen days. In some rare cases, an incubation period of up to 45 days has been reported.
Milder cases can involve flu-like symptoms such as fever, headache, muscle aches, and fatigue. However, Nipah virus can escalate quickly, causing encephalitis in severe cases, which involves swelling of the brain, headaches, confusion, disorientation, drowsiness, altered consciousness and or seizures. Some people develop serious lung disease with breathing difficulties similar to severe pneumonia. In the most serious cases, both the brain and lungs can be affected at the same time.
Dormant or latent infections have been reported months and even years after exposure. This means that some people who appear to have recovered can experience a return of neurological symptoms long after the acute illness has passed, which is an unusual and important feature of this virus.
It is worth knowing that some people infected with Nipah virus experience only mild illness or no symptoms at all. However, given the potential for rapid deterioration, any symptoms developing after potential exposure warrant prompt assessment by a doctor.
Nipah virus diagnosis and treatment
Diagnosis of Nipah virus infection is confirmed by testing bodily fluids. This is typically done through PCR testing of throat swabs, blood, urine, or cerebrospinal fluid. Because Nipah virus symptoms can appear similar to other illnesses, inform your doctor of your travel history.
There is currently no treatment or vaccine available for Nipah virus, however several products are under development. Early intensive supportive care can improve survival, managing oxygen levels, maintaining hydration, controlling seizures if they occur, and preventing further complications as they arise.
Anyone returning from an affected region who develops unexplained fever combined with neurological symptoms or difficulty breathing should call ahead to the hospital or clinic before arriving, so that appropriate isolation and safety measures can be arranged immediately.
Nipah virus prevention
There is currently no treatment or vaccine available for Nipah virus, so avoiding exposure is the only reliable form of protection.
If you are going to an area where Nipah virus has been detected, avoid contact with animals, especially fruit bats and pigs, and areas where bats live. Do not eat fruit that might have been in contact with an animal or their bodily fluids, and 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, particularly in Bangladesh and parts of India. Wash hands thoroughly and frequently with soap and water before eating and after being outdoors in areas where bats or animals are present.
The risk of spread between people can increase in overcrowded, poorly ventilated hospital environments with inadequate implementation of infection prevention and control measures. Travellers who need to visit or support a sick family member in an affected region should avoid unprotected close contact with anyone suspected of having Nipah virus infection. Follow all guidance from local health authorities.