The official in the Health Department here said that the three patients hailed from Puducherry.
They tested positive for the virus after they were examined at the Indira Gandhi Government General Hospital and Research Institute here, and were now under intensive treatment at JIPMER.
The official said two two middle aged women, hailing from the neighbouring Kalapet and Murungapakkam villages, had died of swine flu recently at the JIPMER hospital.
All medical officers have been asked to refer cases of suspected swine flu to the government hospital.A microbiologist had also been deputed to the hospital to collect throat swab samples of those admitted for treatment.
Moderately ill cases would be referred to this hospital while severe cases would be referred to the department of virology in JIPMER, the official said.
Municipal authorities have been asked to control pig menace in their respective areas.