The World Health Organization is stepping up its warnings about contact with camels, urging people to avoid some camel products because they may pose a risk for contracting the MERS virus.

The WHO says people who are at high risk of severe illness if they catch MERS should not have contact with camels, should only consume well-cooked camel meat and pasteurized camel milk and should not drink camel urine, believed by some to have medicinal qualities.

MERS is short for Middle East respiratory syndrome and is caused by a coronavirus of the same name; it is a cousin of the virus that caused the 2003 SARS outbreak.

The virus currently seems to kill about 30 per cent of known cases, though experts acknowledge that figure could be artificially high because testing is mainly geared to finding those who are seriously ill.

The number of diagnosed cases of the new disease have soared over the past six weeks, especially in Saudi Arabia where the bulk of infections have been detected.

In the face of growing concern, on Tuesday the WHO will reconvene an expert panel, known as an Emergency Committee, to advise it on whether MERS should be declared a public health emergency of international concern.

This will be the fifth meeting of the advisory group, which in each previous gathering has expressed concern but said the situation did not meet the threshold for a public health emergency.

On Saturday, the WHO issued updates of its MERS coronavirus "frequently asked questions" and its summary and literature review. The guidance about camels was touched on in both documents, which are posted on the WHO's website.

The Geneva-based agency seems to be trying to walk a fine line on a topic which will be sensitive in the Middle East, where camels are an integral part of life.

The animals provide transportation and are used in religious sacrifices. Camel racing is a popular sport. Some camels, known as the beauties, are kept as pets.

Camels are also raised for food in the Middle East. Unpasteurized camel milk is popular, especially among older people. Some in the Middle East drink camel urine, believing it cures illnesses; others apply it topically to treat skin diseases.

"Camel meat and camel milk are nutritious products that can continue to be consumed after pasteurization, cooking, or other heat treatments," an updated WHO document states.

The recommendation about avoiding camels and some camel products pertains to people with diabetes, kidney failure, chronic lung disease and those who have compromised immune systems; they appear to be at higher risk of becoming gravely ill if they become infected with the MERS virus.

It also notes that sick camels should not be slaughtered for consumption and urges, essentially, that MERS-infected camels should be put in isolation.

"People should avoid direct contact with any animal that has been confirmed positive for MERS-CoV," the FAQ says. That may be easier to say than do. Some studies have suggested the virus does not make camels noticeably ill.

While many mysteries remain about the MERS virus, it has become increasingly clear that camels play a role in its story.

MERS viruses have been isolated from camels. And studies have shown that camels across the Middle East and through parts of North Africa have antibodies to it or a MERS-like virus. But it remains unclear if the animals are the only source of the virus and how people are becoming infected.

The WHO reiterated its frequently repeated call for studies to be done to answer these and other pressing questions.

The MERS virus summary document says the suspected seasonal increase in cases may be linked to the weaning of young camels from their mother, which takes place in the spring.

It says the agency has been informed of 536 cases of MERS since the first known cases in April 2012. Of those, 145 people have died. The WHO's case tally actually lags behind that reported by countries with MERS cases, which is currently closer to 575 cases.

The agency says that while cases have increased substantially since mid-March, the pattern of infections does not appear to have changed. "There is currently no evidence of sustained human-to-human transmission in the community," it suggests.

The WHO notes, though, that until more is known about how the virus is transmitted to people, affected countries will see more cases and countries outside the region need to be on high alert for incoming cases in travellers. Malaysia, the Philippines, Greece and the United States have recently reported a single imported case each.

The new report fleshes out the findings of a recent WHO expert mission to Saudi Arabia, which has seen a substantial spike in cases this spring. The WHO team spent a week in Jidda, where a large hospital outbreak has been occurring.

The team analyzed data on 128 cases diagnosed in Jidda from mid-February to late April. About a third of those people caught the virus outside the hospital, not from another person. But more than 60 people contracted the virus in hospital. Of those, 39 were health-care workers.

Most of the infected health-care workers had few or no symptoms. But about 15 per cent of them developed severe disease and some died, the WHO said.

The summary also provides some detail on a simultaneous, though smaller, surge in cases in the United Arab Emirates. Since late March, the U.A.E. has reported 37 cases to the WHO; two-thirds of the cases have been in health-care workers involved in a large cluster of mostly mild cases.

It also notes that a four year old child from Abu Dhabi contracted the virus. The child's mother had recently returned from Saudi Arabia, where she had performed Umrah, a Muslim pilgrimage. The woman was never tested for the virus, however, so it is not clear if she was the source of the child's infection.