Explained: What is Nipah Virus?

While the rest of the country has been obsessing over the insignia on MS Dhoni’s glove, debating whether aliens took away Indian Air Force’s AN-32 jet, and many such trivial issues, Kerala has been quietly and ably battling the Nipah virus.

This year, a 23-year-old student was admitted in a private hospital in Ernakulam after going to a couple of hospitals in the nearby Thrissur district, where he studies. “He had fever and wasn’t responding to treatment and hence he was brought to Aster Medcity, where they found that he had Encephalitis. As soon as it was found that he had Encephalitis, he was checked for Nipah and it was confirmed,” said Rajeev Sadanandan, the former health secretary, who was also in Delhi recently with the health minister KK Shailaja. His sample has also been sent to National Institute of Virology in Pune for confirmation.

What is Nipah Virus?

The first one heard of this virus was in May 2018 when a critically ill person was brought to Kozhikode’s Baby Memorial Hospital in Kerala. Realising that it might be a virus that they hadn’t tackled before, the doctors sent samples to Karnataka’s Manipal Centre for Virus Research, which is at least 300 km away. The samples tested positive for Nipah virus and then these results were subsequently confirmed by the National Institute of Virology (NIV), Pune.

According to the World Health Organisation, Nipah virus is transmitted from animals such as bats and pigs to humans (zoonotic virus). In Kerala, it was the presence of fruit bats. In infected people, it causes a range of illnesses from asymptomatic (subclinical) infection to acute respiratory illness and fatal encephalitis. The symptoms include 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. Some can also experience 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.

The incubation period (interval from infection to the onset of symptoms) is believed to range from 4 to 14 days. However, an incubation period as long as 45 days has been reported.

When was Nipah first recognised?

Nipah virus was first recognised in 1999 during an outbreak among pig farmers in, Malaysia. During the initial phase, most human infections resulted from direct contact with sick pigs or their contaminated tissues. Transmission is thought to have occurred via respiratory droplets, contact with throat or nasal secretions from the pigs, or contact with the tissue of a sick animal. No new outbreaks have been reported in Malaysia since 1999.

It was also recognized in Bangladesh in 2001, and nearly annual outbreaks have occurred in there since. The disease has also been identified periodically in Siliguri, West Bengal.

How does the Nipah virus spread?

According to the World Health Organisation, in the Bangladesh and India consumption of fruits or fruit products contaminated with urine or saliva from infected fruit bats was the most likely source of infection.

Limited human-to-human transmission of NiV (Nipah Virus) has also been reported among family and care givers of infected NiV patients.

In Siliguri, India, transmission of the virus was also reported within a health-care setting (nosocomial), where 75% of cases occurred among hospital staff or visitors. From 2001 to 2008, around half of reported cases in Bangladesh were due to human-to-human transmission through providing care to infected patients.

In 2018, in Kerala, the first lungs of the first Nipah virus victim had been infected and this meant severe coughs. So, everyone who had been in close proximity of the victim, was found to have been affected. This virus killed 18 in Kerala last year.

The virus spreads between the months of December to June and Kerala had put out a notice asking citizens to be careful. The health department had also warned the hospitals.

Is Nipah Virus found only in Kerala?

No. It is a misconception because it has only been checked in Kerala. “This particular strain of Nipah virus was first found in Siliguri. Bats can fly upto 50 km and if one had to check the bats from West Bengal to Kerala, in all likelihood, most of them would be infected. It wouldn’t have happened in isolation in Kerala. If it hasn’t been found in other states, it is only because no one has checked for it. I am sure if they check patients, who have either encephalitis or respiratory diseases, for Nipah, then more such cases are likely to be found around the country. In Siliguri, it was identified as Nipah, two years after the death of the victim,” explains Sadanandan.

There is a false impression that this is found most in Kerala due to deforestation in the state. “That is not true either. This bat is known to live among human population, eating fruits. They will be seen in forests too and wherever they will find fruits. These bats perform an important function in nature,” emphasises Sadanandan.

Is there a vaccine or a medicine to cure Nipah?

Unfortunately not. There is no medicine for this virus. The US government has classified this virus as an agent of bio-terrorism and they have developed an experimental molecule for which human trials have not yet been conducted.

After extensive research, Sadanandan, in 2018, had found Christopher Broder, an American citizen who had worked extensively on Nipah. Broder is currently working in Malaysia. Broder helped the Kerala government to get in touch with the government in Queensland, where they have developed a monoclonal antibody. Even Australia had completed only Phase – I trial.

In India, for a drug to be used, it should have completed phase 3 trial. It can only be used on compassionate grounds after getting approvals from Drug Controller General of India (DCGI), Indian Council of Medical Research (ICMR). After several rounds of talks, the drug was sourced from Queensland. Since, it has never been administered, no one was sure of the protocol to administer it.

It was then Soumya Swaminathan, who is the daughter of MS Swaminathan, now a deputy director general at WHO, who revived a committee called Nipah Drugs Trial Group. The committee, which was constituted in Geneva had doctors and experts from various countries, including Raman Gangakhedkar representing ICMR, Chandini Sajeevan, head of emergency medicine (Kozhikode Medical College), TK Suma from Alappuzha Medical College and Rajeev Sadanandan.

By the time, these procedures were put in place, the Nipah outbreak had been contained in Kerala in 2018.

What about the 23-year-old in Kerala this year?

The student that was brought in this year had encephalitis, which means the virus had attacked his brain. “On the blood to brain crossover happens, then the monoclonal antibody is not recommended. He has been kept in isolation and has been provided supportive care, and nutrition to help fight the virus. The human body is capable of fighting an external virus and is amazing that way. The student is stable,” explains Sadanandan.

As the virus had attacked his brain, no one else who was in close proximity has been affected. At least 314 of his close associates and caregivers were tested and all their results were negative. “This is because unlike last year’s attack where the first patient’s lungs were infected, this year, the patient’s lung had no infections. Since, his lungs were not infected, it could not have transmitted to others through cough, saliva or droplets in the air,” points out Sadanandan.