Lucknow, Aug 19 - Four new swine flu cases were reported in Uttar Pradesh Wednesday, taking the total number of influenza A (H1N1) patients in the state to 33, health officials said.

Four samples tested positive out of the 50 referred to the Sanjay Gandhi Post Graduate Institute of Medical Sciences (SGPGIMS) here since Tuesday night.

'There was no cause to worry as all patients were carrying only primary infection,' state Health Minister Anant Kumar Misra said.

However, a student of a private engineering college has been detected with secondary infection.

'We are maintaining a constant vigil on the boy. He does not even have fever,' Chief Medical Officer A.K. Shukla told IANS.

T.N. Dhole, the SGPGIMS microbiology department head, said: 'We have sent out the boy's sample for a fresh test.'