New Delhi, Aug 7 - With three doctors being quarantined after being tested positive for swine flu, the Delhi government Friday issued a set of guidelines to schools, colleges and institutions to check the spread of the disease.

Under the guidelines the institutions have been asked to keep a watchful eye on any student or staff member with persistent symptoms of cough, cold and fever and to report such cases to local health officers for monitoring.

'The instructions of the Ministry of Health with regard to influenza A(H1N1) have been issued to the schools, colleges and institutions for managing cases of infection,' said Delhi Health Minister Kiran Walia.

'All hospitals under the Delhi government will screen and counsel swine flu patients, but whether they are to be quarantined will depend on the doctor,' she said.

According to Walia, there are currently 31 swine flu patients in Delhi. Twenty of them are admitted to various hospitals across the capital while the remaining are quarantined at home.

Three doctors in the capital were found to have caught the infection. 'Three doctors have tested positive for swine flu today (Friday),' Delhi Health Secretary J.