Minister of state for health Chandrima Bhattacharya told PTI that three persons were admitted to the hospital from Jagaddal in North 24 Parganas, Howrah and Kolkata districts in the last few days.
Bhattacharya said that one of them was discharged while the other two were still under treatment.
She said that all preventive measures had been taken by the state government in accordance with WHO guidelines.
"We have informed the union health ministry about the swine flu attacks and it has expressed happiness with the health department's measures," she said.