Kerala reports fresh Nipah virus case

• In Kerala, a 43-year-old man was confirmed to have contracted Nipah virus infection and is undergoing treatment at the Kozhikode Government Medical College Hospital.

• Three persons under quarantine have been admitted to hospital for observation and their samples have been sent for testing as part of Nipah surveillance measures in Kozhikode district.

• No new Nipah cases have been reported in the district so far.

Nipah virus

• Nipah virus (NiV), a zoonotic virus (transmitted from animals to humans), has a mortality rate as high as 70 per cent and that is considered to be a pathogen of pandemic potential.

• Nipah virus is a type of Henipavirus naturally held in fruit bats. The virus can cause illness in pigs and humans, and can be spread to humans from animals, infected food and other people with the virus.

• Fruit bats of the family Pteropodidae – particularly species belonging to the Pteropus genus – are the natural hosts for Nipah virus.

• Similar to SARS-CoV-2, NiV is an RNA virus that is transmitted by respiratory droplets. Because of the global pandemic of COVID-19, there is heightened concern regarding respiratory pathogens.

• In infected people, it causes a range of illnesses from asymptomatic (sub-clinical) infection to acute respiratory illness and fatal encephalitis. The virus can also cause severe disease in animals such as pigs, resulting in significant economic losses for farmers.

• Infected people initially develop symptoms including 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 people 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. Most people who survive acute encephalitis make a full recovery, but long-term neurologic conditions have been reported in survivors. 

• Nipah virus was first recognised in 1999 during an outbreak among pig farmers in Malaysia. It was also recognised in Bangladesh in 2001, and nearly annual outbreaks have occurred in that country since. 

• There were outbreaks in India, especially in Kerala, and has so far claimed nearly 20 lives.

• It has been listed as one of the viruses most likely to cause the next pandemic by the World Health Organisation.

• Currently, there are no vaccines licensed for the prevention of Nipah disease. At least eight experimental preventive candidate vaccines against henipaviruses have been evaluated in pre-clinical animal models.