The ongoing battle against Covid-19 and the lessons learned from previous Nipah outbreaks could make Kerala's task easier this time.
The death of a 12-year-old boy on Sunday due to Nipah virus infection has sparked fear of another outbreak in Kerala, a state still struggling with continuous Covid surge.
The boy had symptoms of both encephalitis and myocarditis. His samples were tested at the National Institute of Virology, Pune, which returned positive for the virus. The Centre has already announced that it was sending a team to Kerala to support the state’s public health measures.
The ‘zoonotic’ Nipah virus or NiV is transmitted to humans from animals through contaminated food or directly between people.
The pathogen causing NiV encephalitis is an RNA virus closely related to the Hendra virus found in 1994 in Australia.
The animal host for both these viruses is the flying fox or fruit bat. The infected bats can spread the virus to other animals such as pigs, cats, dogs, horses, goats, and sheep.
Human infections can happen if they come in contact with the infected animal or its fluids such as urine or saliva. Once the infection moves to humans, it can spread from person to person.
Singapore and Malaysia reported the first outbreaks in 1998-99. The Nipah name comes from a Malaysian village, where the first human with the infection died.
In the first outbreak, the virus affected domesticated pigs. Around 100 of the nearly 300 humans infected succumbed to the disease. The authorities also culled a million pigs to contain the spread.
While the region has not seen any further outbreaks, Bangladesh and India have witnessed multiple outbreaks.
The virus appeared in Bangladesh eight times since 2001. The outbreaks in India have been limited to Kerala and West Bengal so far.
Cases in India
Siliguri in West Bengal reported India’s first outbreak in 2001. There were 66 reported cases, while a high mortality rate.
The virus returned in 2007, infecting around 50 people in Nadia district. Around five people died of the virus.
The virus became widely known in 2018 when Kozhikode reported 18 cases, 17 of which resulted in deaths.
Severe Nipah infections can cause major brain swelling (encephalitis) and lead to death.
Symptoms appear from four days to a couple of weeks after exposure. Patients usually suffer from fever and headaches lasting from three days to two weeks. Other symptoms included sore throat, cough, and difficulty breathing.
In case the virus causes encephalitis, patients may feel disorientation, drowsiness, and mental confusion, leading to a coma within a day or two.
The World Health Organization has said the mortality rate varies between 40 and 75 per cent. Survivors have reported long-term side effects such as persistent convulsions and personality changes.
The United States Centres for Disease Control and Prevention (CDC) said cases with ‘dormant’ or ‘latent’ infections, where the symptoms manifest after months or years of exposure have also been recorded.
Earlier Kerala outbreaks
The health department had no experience in handling an infection with such a high mortality rate in 2018. It then followed the Ebola virus disease protocol, tracing the infected person’s contacts and isolating them for 21 days. Once the contacts were traced, the health department prepared their route maps to identify secondary contacts.
All persons with direct or indirect contact with suspected Nipah-infected people were put under observation. Those under isolation were provided psychological aid and counselling to overcome the mental trauma of the fatal outbreak.
The health department contacted those undergoing isolation twice a day and got updates on their health. The government deployed ambulances in the affected regions to immediately pick up patients suspected of being infected. The families of persons under surveillance had been given free ration kits.
When the second outbreak occurred in 2019, the health department had already put in place a protocol. However, only one case was reported in Ernakulam district in 2019.
While the state did not record a Nipah virus case in 2020, the health department updated the protocol and sent it across.
Handling the latest outbreak
While the 2018 outbreak caught the state health department unawares, the situation is different this year.
The ongoing battle against Covid-19 and the lessons learned from previous Nipah outbreaks could make Kerala’s task easier this time.
In 2018, Kerala diagnosed victims only after a few of them had died. This time, the boy’s condition was detected early, with the confirmation coming hours before his death.
However, what is not clear is how he got infected, and if it is the index case.
The index case in 2018 was a 27-year-old who reportedly was infected by fruit bats common in his village in Kozhikode. This time, the victim hailed from Chathamangalam village, 50 km from Changaroth.
In 2018, society at large had no idea of what ‘PPE kits’, ‘contact tracing’, ‘isolation’, and ‘quarantine’ meant. Infection control systems in hospitals were either absent or at a minimal level.
Now, with Covid-19 health protocol in place, health workers are always wearing PPE kits, masks, and gloves while attending patients, especially those with fever.
Kerala reported India’s first case of the global pandemic and it continues to bear the brunt even though other states have managed to control the virus.
Kerala has higher compliance with masking. The Nipah virus spreads mainly through contact with an infected person or their body fluids.
During the 2018 outbreak, most of the infected caught the virus either at Kozhikode Medical College Hospital, where the first victim was admitted, or the Perambra Taluk Hospital.
The droplets of infected persons then infected many victims at hospitals.
The government closed down three wards in Chathamangalam panchayat, where the victim lived, on Sunday morning and has put in place micro-level restrictions.
Kerala has completely banned the to-and-fro movement in these wards, while barricades and checkpoints have come up at locations leading to the victim’s village.