The World Health Organisation has played down the likelihood of the deadly Nipah virus spreading beyond India, stating that it does not recommend imposing restrictions on travel or trade after the South Asian country reported two confirmed infections.
What is striking about the situation?
The fatality rate following infection with the Nipah virus is considered high, ranging between 40% and 75%. To date, there is no approved treatment or vaccine for the virus. Patients rely on early and intensive supportive care to improve their chances of survival.
Current situation
Pakistani authorities have ordered stricter screening measures for incoming travellers to detect symptoms of the deadly Nipah virus after India confirmed two cases.
Thailand, Singapore, Hong Kong, Malaysia, Indonesia, and Vietnam have also tightened airport screening procedures.
An Indian official, however, stated that there are no plans to introduce screening measures at India’s airports.
In Hanoi, the Vietnamese Ministry of Health ordered the screening of passengers arriving at Noi Bai International Airport, particularly those coming from India and the eastern Indian state of West Bengal.
How did it reach humans?
According to the World Health Organisation, the Nipah virus is a zoonotic virus, meaning it is transmitted from animals to humans, particularly from bats. It can also spread through contaminated food or via direct human-to-human transmission.
Origin of the virus
Fruit bats are considered the natural host of the Nipah virus and are found across parts of Asia and Australia. African fruit bats have been found to carry antibodies to Nipah-like viruses, without appearing to suffer from disease.
The virus was first identified in 1998 during an outbreak among pig farmers in Malaysia.
In 1999, an outbreak was reported in Singapore following the importation of infected pigs from Malaysia.
No further outbreaks have been reported in Malaysia or Singapore since 1999.
In 2001, outbreaks of Nipah virus were detected in India and Bangladesh. In Bangladesh, outbreaks have been reported almost every year since then. In India, outbreaks have been reported periodically in several regions, including the most recent outbreak in 2026.
In 2014, an outbreak was reported in the Philippines, with no new cases recorded since that time.
Modes of transmission
The virus can be transmitted to humans through direct contact with infected animals such as bats, pigs, or horses, or by consuming fruit or fruit products contaminated by infected fruit bats. The virus can also cause severe illness in farm animals, particularly pigs.
Nipah virus is also transmitted between humans. Infections have been documented in healthcare settings and among family members and caregivers through close contact.
In healthcare facilities, the risk of transmission increases in overcrowded and poorly ventilated hospital environments, especially where infection prevention and control measures such as personal protective equipment, cleaning, disinfection, and hand hygiene are inadequately applied.
Diagnosis
Distinguishing Nipah virus infection from other infectious diseases, or from other causes of encephalitis or pneumonia, is difficult without laboratory testing.
Patient samples pose a biological hazard. Laboratory testing of non-inactivated samples must be conducted under strict biosafety containment conditions.
Samples from suspected human or animal cases must be handled by trained personnel working in properly equipped laboratories.
The virus is detected using samples from the respiratory tract, blood, or cerebrospinal fluid. Antibody detection in blood samples may also be used.
Symptoms
The incubation period, from infection to the onset of symptoms, ranges from 3 to 14 days. In rare cases, incubation periods of up to 45 days have been recorded.
Some infected individuals may not develop symptoms. However, most patients experience fever, neurological symptoms such as headache or confusion, and respiratory symptoms, including shortness of breath or cough.
Other organs may also be affected. Common additional symptoms include chills, fatigue, drowsiness, dizziness, vomiting, and diarrhoea.
While severe disease can occur in any patient, it is particularly associated with those who develop neurological symptoms, with progression to encephalitis and, in many cases, death.
Most survivors recover fully, but long-term neurological complications have been documented in approximately one in five recovered patients.
Is there a treatment or vaccine?
Although there are no specific treatments for Nipah virus infection, early diagnosis allows for the timely provision of supportive care.
In severe viral infections, high quality supportive medical care can prevent death. This includes identifying complications such as brain swelling, pneumonia, or damage to other organs, and tailoring treatment to the patient’s overall health condition.
Patients may also require oxygen therapy in some cases.
