The World Health Organization is keeping a close eye on a disease outbreak in Saudi Arabia caused by a virus in the same family as the one that caused SARS.

There have been two confirmed infections with the new coronavirus and tests results are pending on a third suspected case, according to media reports from the Middle East. Two of those three people have died.

While word of a coronavirus outbreak immediately brings SARS to mind, there is too little information at this point to say whether this is anything more than a blip on the viral radar.

Still, with pilgrims beginning to gather in Saudi Arabia for next month's Hajj, the public health community is on alert.

"As with any new virus, this is of concern to us and we're watching it very closely," WHO spokesperson Gregory Hartl said Sunday.

SARS killed 775 worldwide

There are a large number of coronaviruses. Some infect animals, others infect birds and still others infect people. In humans, coronaviruses typically cause colds.

But a coronavirus was also the cause of the 2003 outbreak of severe acute respiratory syndrome or SARS, which killed 44 people in Toronto and about 775 people worldwide.

The new coronavirus reportedly causes severe pneumonia and kidney failure.

One of the confirmed cases is in intensive care in a hospital in London, Britain's Health Protection Agency said Sunday.

A statement from the WHO said the person is a 49-year-old man from Qatar who had travelled to Saudi Arabia before he became sick. He was admitted to intensive care in Doha on Sept. 7, but was transferred to Britain by air ambulance on Sept. 11.

"Given that this is a novel coronavirus, WHO is currently in the process of obtaining further information to determine the public health implications of these two confirmed cases," the WHO statement said. It did not refer to the third suspect case.

Professor John Watson, head of the respiratory diseases department at the Health Protection Agency, said to date there is no sign of spread to health-care workers.

That is important because health-care workers often serve as inadvertent sentinels of the spread of infectious diseases. During SARS, for instance, health-care workers were disproportionately affected, catching the new virus from patients they were struggling to save.

"Preliminary enquiries have revealed no evidence of illness in contacts of these two cases, including health-care workers," the British agency's release stated.

"Based on what we know about other coronaviruses, many of these contacts will already have passed the period when they could have caught the virus from the infected person."

That said, the British agency's release said there have been other cases of serious respiratory illness in the Middle East over the past three months, including in another person who was treated in Britain. That person has since died, the HPA said.

"This person's illness is also being investigated although there is no evidence at present to suggest that it is caused by the same virus or linked to the other two cases. No other confirmed cases have been identified to date in the UK."

A report on the discovery of the new coronavirus appeared last week on ProMED-mail, an Internet-based system for monitoring infectious diseases around the world.

Dr. Ali Mohamed Zaki, a microbiologist from a hospital in Jeddah, revealed that a new coronavirus had been recovered from a 60-year-old man suffering from pneumonia and renal failure. Zaki said the new virus was part of a group of coronaviruses that are closely related to bat coronaviruses.

No current travel restrictions

Tests to confirm that the virus is indeed a newly identified one were conducted at the lab of Dutch microbiologist Ron Fouchier, a leading influenza researcher at the Erasmus Medical Centre in Rotterdam.

In an email Sunday, Fouchier said his team compared the genetic sequence of the virus they received from Zaki to that isolated from the patient in London.

"The two pieces were 99.5 per cent identical. Although it thus seems that the two cases were caused by the same virus, this is still a premature conclusion," he wrote, cautioning his team had only a small sample of sequence data from the London case to compare to their virus.

The WHO statement said work done in Britain to compare the two viruses also showed they were 99.5 per cent alike.

The WHO is not recommending any travel restrictions at this time.

This year's Hajj is expected to take place between Oct. 24 and 29, but according to the Saudi Arabian government's Ministry of Hajj website, the first day for pilgrims to begin to arrive in the Kingdom was Sept. 17.

The annual Islamic pilgrimage draws hundreds of thousands to the Saudi city of Mecca. The Hajj is one of several large global events — the Olympics are another — that are a constant source of concern for public health officials because of their capacity to spread diseases to many parts of the globe.