Lapses in hospital infection control measures exacerbated an outbreak of a deadly new viral disease which has infected more than 60 people and killed at least 10 in the UAE, health investigators said.

Reporting the findings of a five-day mission to the UAE, experts from the World Health Organisation said, however, that they found no evidence of sustained human-to-human transmission of new Middle East Respiratory Syndrome coronavirus (Mers-CoV).

"The recent upsurge of cases in Abu Dhabi appears to have been caused by a combination of factors, including a breach in infection prevention and control measures in health care settings, active surveillance and increase in community acquired cases," they said in a statement.

First reported in humans in 2012, Mers causes severe and often fatal respiratory illness, with symptoms similar to those seen during the outbreak of severe acute respiratory syndrome (Sars) in 2003.

Its around 40 per cent death rate and reports of clusters of human-to-human transmission have raised concerns it may blow up into a pandemic.

So far, it has infected more than 800 people around the world, killing at least 310 of them. The vast majority of cases have been in Saudi Arabia, but there have also been sporadic cases and clusters across the Middle East and in Europe, Asia and the United States.

At the heart of the outbreak, Saudi Arabia has been criticised for its handling of Mers, which public health experts say could have been under control by now if officials and scientists there had collaborated more on studies into how the virus operates and where it is coming from..

In response, the Saudi health ministry says it has put in place new measures for better data gathering, reporting and transparency, including standardisation of testing and improved guidelines for labelling and storing samples.

Reporting on the UAE's handling of the problem, the WHO praised authorities there, saying they had been "following up diligently" on Mers cases, including conducting repeated tests to check when cases have been cleared of the virus.

"This data will make an important contribution to the risk assessment and to guide the health response internationally," said Peter Ben Embarek, who led the WHO delegation.

A six-strong team from the WHO and the Global Outbreak Alert and Response Network were invited by the UAE to investigate Mers after an upsurge in cases there in April.

The team met experts from Health Authority Abu Dhabi, Dubai Health Authority and the Abu Dhabi Food Control Authority, and visited the hospital to which two-thirds of the country's cases had been be traced, it said, without giving its name or location.

"We are impressed by the amount of data and information generated during the investigation of Mers cases by UAE to help better understand Mers- CoV," Ben Embarek said.

"This knowledge is of utmost importance to the rest of the world to better discover the source of the virus and the routes of transmissions from animals to humans."

The Geneva-based UN health agency urged UAE health authorities to continue investigating Mers, including the source of infection, and to share new information as it is available.

"There is an ongoing need to share experiences and knowledge from all countries that have cases of Mers-CoV to better understand this emerging disease, including the role of animals in the spread of the Mers-CoV," it said.-Reuters