Nipah infection symptoms range from asymptomatic infection, acute respiratory infection and encephalitis.

Union Health Minister Harsh Vardhan today said no new case of Nipah virus infection has been reported in Kerala and informed that the clinical condition of the patient suffering from the disease, the only case this year, is improving.

A case of Nipah was reported from Kerala's Ernakulum district on June 3 and the condition of the infected college student is improving, Mr Vardhan said.

The Nipah virus had claimed 17 lives in the state in May last year.

As on Sunday, blood and serum samples of all seven suspected patients who were admitted at a quarantine facility at the Government Medical College in Kerala's Ernakulam district have tested negative for the virus, while the sample from the eighth patient is being tested, the minister said.

On Saturday, four patients from the isolation unit were discharged as their clinical condition improved.

National Institute of Virology (NIV), Pune has collected three blood samples from pigs and about 30 samples from bats from Thodupuzha in Idukki district of the state for testing.

Experts from National Institute of High Security Animal Diseases (NIHSAD) in Bhopal are supporting Kerala's Animal Husbandry Department in the investigation. Multi-disciplinary central teams, including experts from the the NCDC, AIIMS and ICMR, have been deployed to support the state in conducting contact tracing, sample testing and management of the infection.

A designated control room has also been established at the district collector's office and isolation facilities have been set up at medical colleges in Calicut, Thrissur and Kottayam.

All healthcare facilities have been asked to ensure high index of suspicion in cases with similar symptoms and also ensure availability of isolation and emergency management facilities before referral.

According to the World Health Organisation, Nipah virus infection is a newly emerging disease that can be transmitted from its reservoir (natural wildlife host), the flying foxes (fruit bats), to both animals and humans.

Symptoms range from asymptomatic infection, acute respiratory infection and encephalitis.

Infected people initially develop influenza-like symptoms of fever, headache, vomiting and sore throat. This might get followed by dizziness, drowsiness, altered consciousness, and neurological signs that indicate acute encephalitis.