* U.N. health agency gives global guidance on reporting new virus
* Two cases so far, Saudi and Qatari who went to Saudi
* WHO working with Saudi authorities ahead of haj next month
* Six suspected cases in Denmark prove to be false alarms (Updates with suspected cases cleared in Denmark, Saudi measures, ECDC comment)
By Stephanie Nebehay
GENEVA, Sept 26 (Reuters) - The World Health Organization on Wednesday urged health workers everywhere to report patients with acute respiratory infection who may have been in Saudi Arabia or Qatar, following the discovery of a new virus from the same family as SARS.
Saudi Arabia said it had taken precautions to prevent disease spreading next month, when it expects over 2 million Muslims to flock to the annual haj pilgrimage, then return home.
WHO put out a global alert on Sunday saying a new virus had infected a 49-year-old Qatari who had recently travelled to Saudi Arabia, where another man with an almost identical virus had died.
The Qatari remained critically ill in hospital in Britain as of Tuesday, but the WHO said on Wednesday no new case of the new virus had been reported.
"We've got things in place should things change, should the behaviour of the virus change," spokesman Gregory Hartl said.
Tests showed that six people with respiratory infections in two hospitals in Denmark did not have the new coronavirus, and at least five of them had flu, Danish health officials said.
The new virus shares some of the symptoms of SARS, another coronavirus, which emerged in China in 2002 and killed around a tenth of 8,000 people it infected worldwide. So far scientists do not know how contagious the new virus is, or whether or not it spreads by contact between people.
WHO's clinical guidance to its 194 member states said health workers should be alert to anyone with acute respiratory syndrome and requiring hospitalisation who had been in the area where the virus was found or in contact with a suspected or confirmed case within the previous 10 days.
WHO has not recommended any travel restrictions in connection with the new virus, but said it was working closely with Saudi authorities on health measures for the haj.
WHO said it was identifying a network of laboratories that could provide countries with expertise on coronaviruses.
"Though it is a very different virus from SARS, given the severity of the two confirmed cases so far, WHO is engaged in further characterising the novel coronavirus," it said.
The European Centre for Disease Prevention and Control in Stockholm said that, based on the available information, "ECDC assesses the current risk as low". (Reporting by Stephanie Nebehay; additional reporting by John Acher in Copenhagen, Alistair Scrutton in Stockholm, Kate Kelland in London and Asma Alsharif in Jeddah; Editing by Kevin Liffey)