The Union health secretary has written to chief secretaries of all the state governments and Union Territories to isolate and treat people found to be suffering from Severe Acute Respiratory Syndrome (SARS), a deadly form of pneumonia.

The disease has so far claimed about fifty lives around the world.

He has asked the states to keep a close watch on travellers coming from Singapore, Thailand, China and Hong Kong.

As a precautionary measure, Air-India has curtailed its flights to Hong Kong and would now fly on this sector only thrice a week.

Though no case of SARS has emerged in India so far, the health ministry is not taking any chances, Director General of Health Services Dr S P Aggarwal told rediff.com.

"Health officers posted at the major international airports have been instructed to keep an eye on travellers running high fever and suffering from acute cough."

"The ministry of civil aviation would be handing over cards to disembarking passengers wherein they would have to give details of recent ailments, if any."

"This could help us in isolating any case of SARS," Dr Aggarwal said.

"The disease spreads through long contact with patients. Those who fall in the risk category include doctors, nurses, health workers and close relatives of the patients," he informed.

On March 17, Union Health Minister Sushma Swaraj presided over a meeting of doctors from her ministry and top government hospitals and passed orders for immediate action in this regard.

"We are monitoring the situation but as of now there is no cause for alarm," Dr Aggarwal said.

Dr Randeep Guleria, the prime minister's personal physician, said, "It is a contagious disease and one needs to be careful. A patient discharges infectious germs when he/she coughs."

"However, we need to stress that this disease is curable," he added.