If the immune system is weak, the organs will fail,' said Shanmugasundaram, another doctor at Mehta Children's Hospital.

'The cause of death will have to be investigated as the boy was suffering from asthma and several of his vital organs failed,' S. Illango, director of public health and preventive medicine department, told IANS.

He said the body will soon be handed over to the family for the last rites.

P. Kuganathan, health officer of the corporation of Chennai, said: 'The deceased boy's brother is admitted in the Communicable Diseases Hospital and is free from complications. Other members of the family have tested negative.'

He said that 138 people in the city were tested for swine flu and 45 were positive. Out of them, 31 had been treated and discharged.

According to a central government health official, 42 people have tested swine flu positive in Tamil Nadu but no case has been reported in nearby Puducherry.

'We are taking all preventive steps like creating awareness. All hospitals will be given Tamiflu tablets. Preventive medication is being given to the people who came in close contact with the boy who died in the morning,' he said.