LONDON, June 5 (Reuters) - A dramatic upward revision in the number of people killed by the MERS virus in Saudi Arabia may signal a fresh approach from Riyadh, but also raises new questions about how the two-year-old outbreak has been handled.
Experts in global health and infectious diseases say transparency with data is critical to learning more about the virus, which until two years ago had never been seen in humans but has now killed more than 300 people worldwide.
And while an announcement on Tuesday that a historical review of the outbreak had revealed 113 previously unreported cases, including 92 deaths, suggested greater openness, some scientists said international health authorities may have been kept in the dark.
"It really calls into question why these cases weren't reported before - particularly those that are at least two or more months back in time," said Michael Osterholm, director of the Center for Infectious Diseases Research and Policy at the University of Minnesota.
"From the information we have available I don't think we can tell why (they weren't reported before). But it's one of two reasons - one, it was incompetent surveillance that was not properly set up to be able to detect and confirm these cases, or two, it was an intentional effort not to report some cases, particularly the more severely ill and fatal cases."
Tariq Madani, head of the scientific advisory board in the Saudi Health Ministry's command and control center, said he did not believe the under-reporting had been deliberate, and was due to a range of factors.
"We don't think this was intentionally done, intentionally under reported. This can happen anywhere in the world, that 20 percent of patients may not be reported. This is within the limit. It's actually less than 20 percent," he said.
The Middle East Respiratory Syndrome (MERS) virus, which can cause fever, coughing, shortness of breath and pneumonia, is thought to be transmitting into humans from camels, although scientists say human-to-human spread is also taking place.
The Saudi agriculture minister was reported on Thursday as saying the kingdom's camels would be tested.
Saudi Arabia has already been criticized for its handling of the outbreak, which public health experts say could have been under control by now if officials and scientists there had been more willing to collaborate on studies into how the virus operates and where it is coming from..
In response, the health ministry says it has put in place new measures for better data gathering, reporting and transparency, including standardization of testing and improved guidelines for labeling and storing samples.
On Monday, acting health minister Adel Fakieh announced he had dismissed deputy health minister Ziad Memish from his post. Fakieh was appointed in April after King Abdullah sacked his predecessor Abdullah al-Rabeeah following a surge in MERS cases.
On Tuesday the ministry revealed a jump of nearly 50 percent in MERS deaths in a data review that also showed the number of cases since 2012 was a fifth higher than previously reported.
Latest Saudi figures show a total of 691 MERS cases in people there, of which 284 have been fatal.
The European Centre for Disease Prevention and Control (ECDC) said it was not clear whether the new cases met the World Health Organisation's definition of confirmed cases and noted that they had been reported without key details.
"Information about age, gender, residence, probable place of infection, whether the case is sporadic/primary or part of a cluster of secondary transmission, health care associated transmission or not, and whether the case is a healthcare worker, is missing," the ECDC said.
The health ministry's Madani said that although only limited data was published on the ministry's website, more detailed data was available to scientists and healthcare professionals who contacted the ministry directly.
Ian MacKay, an associate professor of clinical virology at Australia's University of Queensland who has been tracking the MERS outbreak since the virus was first identified almost two years ago, told Reuters he remained skeptical about how transparent the new officials would be.
"I'm fairly doubtful about the whole process," he said in a telephone interview. "We're seeing all this under a banner of increased transparency, and yet there's no information about what these 113 cases are, about where or how they were tested, or what age they are. There's really very little information, so I'm very dubious about what this is supposed to tell us."
The United Nations' public health arm, the World Health Organization, said its experts were in Saudi Arabia providing technical advice.
"The recent appointment of a new Minister of Health has resulted in renewed energies and greater government commitments to address the challenges linked to MERS. WHO welcomes all efforts to gather and verify information and support the sharing of information about MERS," it said.
Osterholm said international scientists and health authorities should encourage Saudi Arabia to stick to its word.
"MERS is not a Kingdom of Saudi Arabia problem, and it's not a Middle East problem, it's an international problem - and it takes an international response to deal with it," he said, noting that people infected with the virus have already imported cases from the region into Europe, Asia and the United States.
"Imagine if tomorrow one of these air passengers turned out to be a super shedder of the virus and ends up in London or New York or Hong Kong or Toronto. The world would change overnight."
Additional reporting by Angus McDowall in Riyadh, editing by Philippa Fletcher