India Nipah virus: Symptoms, origins and everything you need to know

India’s southern state of Kerala has reported its first death from a new outbreak of the Nipah virus after a 12-year-old boy died of the infectious disease on Sunday, even as the state battles a deadly Covid-19 surge that accounts for a significant chunk of the country’s daily caseload.

At least two health workers have also been infected in the state, according to local reports.

This is the first death reported from the viral disease in Kerala after nearly three years, prompting health officials in it and neighbouring states to go into a state of alert.

The disease is usually caused by the consumption of food contaminated by animals, mostly bats. The virus carries a high fatality rate, ranging from 40 per cent to 75 per cent.

The administration’s health officials have cornered at least one likely source of the infection: Rambutan, a lychee-like fruit consumed by locals. Officials are attempting to identify whether the infection was carried through the fruit after bats contaminated it, said a Hindustan Times report.

Officials have also identified 18 family members and relatives who came in contact with the infected 12-year-old boy, and quarantined 150 secondary contacts.

Officials from Delhi’s National Centre for Disease Control have tried to identify the fruits the boy may have consumed and any animals he could have interacted with, the report added.

Locals have been advised to follow protocols after the Kerala administration declared the area around the victim’s house a containment zone and imposed lockdown-like rules within a three-kilometre radius.

The Nipah virus case has raised fears of an outbreak of another disease after Covid, even as Kerala accounts for at least 50-60 per cent of the country’s daily Covid cases.

The southern state alone also reported more than 26,000 cases and 74 deaths in a span of 24 hours on Sunday, according to official data, keeping state authorities in a state of alert as they remain wary of a possible third wave.

What is Nipah virus

According to the World Health Organisation (WHO), Nipah is a zoonotic virus, which means it is transmitted from animals to humans. The virus can also be transmitted through contaminated food and has been directly transmitted between people in some cases.

The Nipah virus causes a range of illnesses. Some patients remain asymptomatic, but others exhibit acute respiratory symptoms and fatal encephalitis. It is also known to infect a number of animals, especially pigs, impacting local livestock trade among farmers.

What is the origin of Nipah virus

The virus was first recognised in 1999 in Malaysia, after an outbreak was reported among pig farmers. The second time the Nipah virus reared it head was in 2001 in Bangladesh, which is also India’s neighbour.

Bangladesh has since then continued to report annual outbreaks, according to the WHO. There have also been reports of cases in eastern India after 2001.

Several other countries are also said to be at risk, as evidence of the virus has been found in several bat species that are found in countries like Cambodia, Ghana, Indonesia, Madagascar, the Philippines and Thailand.

How is Nipah virus caused

The disease is carried by fruit bats of the family Pteropodidae – particularly species belonging to the Pteropus genus – who are the natural hosts of the Nipah virus. It can be transmitted between animals, animals to humans via contaminated food and among humans via direct contact.

What are the symptoms of Nipah virus

A person infected with Nipah will initially develop symptoms like fever, headaches, myalgia (muscle pain), vomiting and sore throat. “This can be followed by dizziness, drowsiness, altered consciousness and neurological signs that indicate acute encephalitis,” according to the WHO.

An infected person also experiences atypical pneumonia and severe respiratory problems, including acute respiratory distress. “Encephalitis and seizures occur in severe cases, progressing to coma within 24 to 48 hours,” says the WHO.

What is the incubation period of Nipah virus

The interval from infection to the onset of first symptoms is believed to fall between four and 14 days. In certain cases, an incubation period spanning 45 days has also been reported.

What happens to those who contract Nipah virus

While some remain asymptomatic and most who survive Nipah virus make a full recovery, others have reported long-term neurological conditions.

“Approximately 20 per cent of patients are left with residual neurological consequences such as seizure disorder and personality changes. A small number of people who recover subsequently relapse or develop delayed onset encephalitis,” the WHO says.

How can Nipah virus be treated

At present, there are no drugs or vaccines specifically designed to counter the Nipah virus. The global health body has recommended intensive supportive care to treat severe respiratory and neurological complications for this “priority disease” under its Research and Development Blueprint.

When did India last report the Nipah virus

India reported its last Nipah virus case in 2019 in Kerala, but it was quickly contained by the state administration without reports of deaths or any further infections taking place. Before that, Kerala grappled with an outbreak in 2018 that had led to the death of 17 people.

Kerala announced it had overcome this outbreak on 10 June 2018.

The very first Nipah outbreak in India occurred in 2001 in Siliguri in the state of West Bengal, in which 45 people died, followed by a second outbreak in 2007, in which five died from the infection.

How can a Nipah outbreak be prevented

Animal premises, in case an outbreak is suspected, should be quarantined immediately, according to the WHO. “Culling of infected animals – with close supervision of burial or incineration of carcasses – may be necessary to reduce the risk of transmission to people,” it says.

The movement of animals from infected farms to other areas should be restricted or banned to reduce the spread of the disease.

“As Nipah virus outbreaks have involved pigs and/or fruit bats, establishing an animal health/wildlife surveillance system, using a One Health approach, to detect Nipah cases is essential in providing early warning for veterinary and human public health authorities,” the WHO says.

Human-to-human transmission can be stopped by avoiding close unprotected physical contact with those infected by the Nipah virus. Regular hand washing should be carried out after caring for or visiting sick people.

Humans can avoid the risk of transmission via contaminated fruits or fruit products by washing them thoroughly and peeling them before consumption. Fruits with signs of bat bites should be disposed of, according to the WHO.