The World Health Organisation put out a global alert on Sunday saying a new, previously unknown, virus had infected a 49-year-old Qatari man who had recently travelled to Saudi Arabia, where another man with an almost identical virus had already died.

Britain's Health Protection Agency and respiratory disease experts said there was no immediate cause for concern, although authorities were watching for any signs of the virus spreading.

Muslims from some 160 countries flock to Mecca and Medina during the annual Haj pilgrimage, which begins in late October. Some arrive by plane, others by boat or by car.

"The Health Ministry has taken preventative measures to deal with the influx of over 2 million Haj pilgrims," Ziad Memish, the deputy minister for public health, told Reuters.

"The measures include monitoring the entrances through land, sea and air to evaluate the people entering and obtain samples if any symptoms are apparent," he added.

In 2009 Saudi Arabia set up thermal cameras at its airports and increased the number of its medics as part of its measures to limit the spread of the H1N1 flu. It will not resort to using thermal cameras this year, Memish said.

"There is also continuous monitoring in the holy places in Mecca and Medina and Jeddah, with teams on the ground and hospitals to deal with them." (Reporting by Asma Alsharif; Editing by Stephen Powell)

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