India is responding to a rare (but serious!) outbreak of Nipah virus (NiV) in the eastern parts of the country, with health authorities and the World Health Organization (WHO) looking it as a potential threat.
While only two laboratory-confirmed cases of this infection have been reported in West Bengal since late December 2025, the healthcare professionals across the country are up on their toes, closely monitoring the situation.
Firstpost speaks to Dr. Shachi Pandit (Consultant Pulmonologist, Narayana Hospital, Ahmedabad) and Dr. Anaita Hegde, (Senior Consultant–Paediatric Neurology & Head, Neuroscience Department, Narayana Health SRCC Children’s Hospital, Mumbai) to understand what really happens if Nipah virus enters your body.
Nipah virus starts ‘quietly’ and ‘much earlier’ than you’d know
According to Dr. Pandit, Nipah virus is often feared for the serious damage it causes to the brain, but its story usually begins much earlier and far more quietly.
In many patients, the illness starts like a simple upper respiratory infection – something most people would not think twice about.
A fever that refuses to settle, a sore throat, a mild cough, or cold are often the first warning signs. At this initial stage, the symptoms can look deceptively similar to flu or COVID-19, leading many to delay seeking medical care.
The respiratory point of view
Dr. Pandit shares that as the infection progresses, the lungs may become involved.
“In the intermediate stage, breathing can turn difficult, oxygen levels may begin to fall, and severe pneumonia can develop. Some patients deteriorate rapidly, with lung damage progressing to Acute Respiratory Distress Syndrome (ARDS), a life-threatening condition that requires intensive care,” she adds.
These respiratory symptoms are especially concerning because coughing significantly increases the risk of the virus spreading from one person to another, putting family members and caregivers at risk.
Here’s what happens, step by step:
Step 1: Virus reaches the lungs – After entering the body, Nipah can infect the cells lining the respiratory tract and lungs.
Step 2: Inflammation sets in – The immune system responds aggressively, causing inflammation of lung tissue, which makes breathing harder.
Step 3: Fluid leakage into air sacs – The tiny air sacs (alveoli) can start filling with fluid – a condition similar to viral pneumonia – reducing oxygen exchange.
Step 4: Acute respiratory distress – In severe cases, this progresses to acute respiratory distress syndrome (ARDS), where the lungs become stiff and oxygen levels drop dangerously.
Step 5: Higher transmission risk – When the lungs are involved, patients may develop cough and breathing difficulty, increasing the risk of person-to-person spread through respiratory droplets, especially in close-contact or healthcare settings.
Notice the early signs:
Patients may develop a dry cough, mild shortness of breath, chest tightness, or sore throat, sometimes accompanied by rapid breathing or low oxygen levels even without obvious distress.
These symptoms often appear alongside fever, headache, and fatigue and can worsen quickly, progressing to pneumonia or acute respiratory distress.
Red flags such as increasing breathlessness, bluish lips, or confusion require immediate medical attention to prevent severe complications.
The brain point of view
Speaking to us, Dr. Anaita Hegde shares “the virus not only affects general health, but also the overall nervous system of an individual.”
The distinctive fact about this virus is its strong ability to attack the central nervous system (CNS). Once it manages to break into the body through the respiratory tract, the virus enters the bloodstream after crossing the blood-brain barrier – a protective shield that prevents harmful pathogens from affecting the brain.
Once inside the CNS, the virus triggers a serious response, often leading to inflammation of the brain (encephalitis).
Survivors may experience long-term neurological effects
Dr. Hegde further clarifies that initially, on clinical observation, these symptoms tend to be misunderstood for other complications. However, many patients can report a rapid change from mild symptoms to life-threatening neurological dysfunctions in a matter of just a few days.
In fact, survivors of Nipah may also experience long-term neurological sequelae, including persistent seizures and cognitive or personality changes.
Here’s what happens, step by step:
Step 1: The virus crosses into the brain – Nipah can breach the blood–brain barrier and infect neurons and the cells lining brain blood vessels.
Step 2: Acute encephalitis develops – This triggers swelling and inflammation of the brain (encephalitis), disrupting normal brain function.
Step 3: Blood vessel damage – Nipah causes inflammation of small blood vessels in the brain, leading to tiny hemorrhages and reduced blood flow, which further injures brain tissue.
Step 4: Rising pressure inside the skull – As the brain swells, intracranial pressure increases, which can impair consciousness and vital functions.
Step 5: Electrical disturbances – Damaged brain tissue can trigger seizures, confusion, and abnormal movements.
Step 6: Loss of consciousness – In severe cases, patients may rapidly progress to coma within days.
Notice the early signs:
Early recognition of neurological signs and symptoms in children, including frequent vomiting, drowsiness and new-onset seizures, is extremely essential.
Immediate supportive care in a tertiary facility equipped with intensive neurological monitoring can make a significant difference in outcomes.
Are there any medicines or treatments available yet?
Dr. Hegde says that at present, there is no specific antiviral treatment, so public awareness, early detection and prompt supportive management remain central to controlling the impact of this high-fatality pathogen.
There is no licensed vaccine either. Care is mainly supportive, including oxygen therapy, intensive care, and management of complications.
FAQs – all your questions answered, to the point!
What is Nipah virus?
Nipah virus (NiV) is a zoonotic virus – it spreads from animals (primarily fruit bats) to humans. It can also spread between humans through close contact and causes respiratory illness and encephalitis (brain inflammation).
How is Nipah virus transmitted?
Transmission can occur through direct contact with infected bats or their secretions, contaminated food (e.g., raw date palm sap), and close contact with infected humans.
How quickly do symptoms appear after infection?
Typically 4–14 days after exposure, but severe cases can escalate rapidly once respiratory or neurological symptoms appear.
How is Nipah virus detected?
Through laboratory tests, including PCR and serology, conducted by national reference labs like the National Institute of Virology (NIV) in Pune.
Is Nipah virus fatal?
Yes, it has a high case fatality rate, historically ranging from 40% to 75% depending on outbreak severity and medical care.
Can Nipah virus survive outside the body?
It can survive for a short time in body fluids, contaminated surfaces, and certain foods, but it is not airborne over long distances like influenza.
What should people do if they develop symptoms?
Anyone in outbreak areas with fever, cough, or breathing difficulty should seek immediate medical care, avoid contact with others, and follow public health guidance.
How is India controlling the outbreak?
Authorities are conducting contact tracing, isolation of cases, hospital infection control, and surveillance. WHO and local governments have stated that the risk of wider spread is low.
Can Nipah virus spread globally?
Human-to-human transmission is limited, so the risk of a global outbreak is low, but countries are monitoring travellers from affected areas.