Kolkata, Aug 18 - A two-and-a-half year old critically ill boy was on ventilator support while former Indian cricket captain Sourav Ganguly's niece remained stable as the number of confirmed swine flu cases shot up to 53 in West Bengal Tuesday.

'Six people tested positive for the Influenza A(H1N1) virus Tuesday, and the total number affected is now 53,' Tapan Sen, the state's nodal officer for swine flu, told IANS.

Sen said that Akash Chowdhury, under treatment at the intensive care unit of the state-run R.G. Kar Medical College and Hospital, was put on ventilator support as his condition had become critical.

Eleven year old Sneha, daughter of Soruav Ganguly's elder brother, was 'stable' and 'making satisfactory progress' at the swine flu isolation ward of the state-run M.