A two-member surveillance team of the state health department visited a village in Kaliachak 1 block of Malda district on Friday and spoke to family members of the four-year-old boy infected with H9N2 virus, often called bird flu.

The department's joint director Dipankar Majhi and deputy director Binay Biswas reached the village, along with district health officials, to take stock of the situation.

In January, the minor was showing symptoms of influenza. The virus was detected on April 26 and the patient was treated in NRS Medical College & Hospital. He was released on May 1.

Recently the case, the second of its kind in the country, was published by the World Health Organisation (WHO) in its magazine. In 2019, the first case was detected in Maharashtra.

The child's family members said he still had breathing troubles and had to be provided with artificial oxygen regularly. This made the health officials arrange an oxygen concentrator for the boy.

Sources have said the common bird flu virus is H5N1.

“H9N2 is a different virus of the same avian influenza group. But this does not get communicated from human to human,” said Sudipta Bhaduri, the chief medical officer of health of Malda.

He said all 14 members of the boy’s family had already been screened. “None of them was found to have contracted the virus,” said Bhaduri.

The team members were told that there was no poultry near the patient’s house which left them wondering how he got infected.

Later, they visited the Kaliachak 1 block hospital and the influenza testing unit in Malda Medical College & Hospital, said sources.