All the seven persons were tested for H1N1 virus after they showed flu-like symptoms.

The samples were sent to National Institute of Communicable Diseases (NICD) for testing. Six of the samples have tested negative, said Director NICD Shivlal.

"The samples were put through a rapid test for ‘influenza A’ virus for which they tested negative. Further tests for H1N1 flu were not required as only ‘influenza A’ virus can lead to swine flu," he said.

While six samples were sent from the Ram Manohar Lohia hospital, one was that of a person from Hyderabad who had reported symptoms last week.

Five persons were discharged from the hospital while a London-based NRI is still admitted to the RML as his test results have not come yet.

Five persons were brought to RML in the past 24 hours while one person from Ghaziabad, who has recently returned from Texas, voluntarily came to the hospital after he saw media coverage of the flu.

While the 35-year-old London-based NRI was brought to hospital directly from the Indira Gandhi International Airport this morning, the 25-year-old who came from Texas got himself admitted to the RML last evening.

"Both of them are under observation in isolation ward. We have done all tests and samples have been sent to NICD," N K Chaturvedi, Medical Superintendent of RML, told reporters.

The London-based NRI, who hails from Delhi, developed flu symptoms during his flight to the capital from London and was referred to the hospital after a screening at the airport.

"He has a running nose, sore throat and cold but has no fever. He will be kept under observation for the next three days," Chaturvedi said.

The Texas-based youth, who landed in Delhi on April 19 and had fever for two days on April 24, turned up at the hospital last evening, Chaturvedi said adding the man, who hails from adjoining Ghaziabad, later became asymptomatic.

Vineet Chaudhary, Joint Secretary in Health Ministry, said there was no case of H1N1 flu in the country and all precautions have been taken.