Graphic: Mallory Brangan

Graphic: Mallory Brangan

Cairo: As the number of reported cases of the potentially deadly Middle East Respiratory Syndrome surged this week, public health experts are struggling to understand where it originated, how it is spread and why there has been a sudden spike in infections.

In the past week, significant outbreaks occurred in Saudi Arabia's coastal business hub of Jeddah and in the neighbouring United Arab Emirates' capital Abu Dhabi, both involving healthcare workers, infectious diseases experts said.

The World Health Organisation is particularly worried these two clusters could indicate there is an "evolving risk" in the spread of MERS. Pointing to "critical information gaps" regarding the transmission of the virus, it has offered to work jointly with national health authorities in Saudi Arabia and the United Arab Emirates to investigate the outbreaks in order to determine the transmission chain.

A thermal scanner in use at Manila's international airport. The Philippines reported its first case of the MERS virus in the past two weeks.

A thermal scanner in use at Manila's international airport. The Philippines reported its first case of the MERS virus in the past two weeks. Photo: AP

It is not yet clear whether either country has taken it up on the offer.

Neighbouring countries, as well as those whose nationals make up Saudi Arabia's large foreign workforce, are growing increasingly worried about the kingdom's apparent slow response to the virus.

Malaysia, Greece, Yemen and the Philippines all reported their first cases of the virus in the past two weeks - all the sufferers had been working or travelling in Saudi Arabia.

A significant outbreak of the virus occurred in Saudi Arabia's business hub of Jeddah in the past week.

A significant outbreak of the virus occurred in Saudi Arabia's business hub of Jeddah in the past week. Photo: AFP

The Saudi Arabian Ministry of Health reported 14 new cases on Wednesday and Thursday alone, as well as four deaths among previously notified patients. This brings the Saudi total to 299 cases and 87 deaths since the virus was first recognised in 2012, the ministry said on its website on Thursday.

Internationally, about one-third of those affected have died. The total number of confirmed infections worldwide is 345, with 107 deaths, the European Centre for Disease Prevention and Control in Sweden reported on Thursday. The bulk of these infections are in Saudi Arabia and the UAE.

"Approximately 75 per cent of the recently reported cases ... have acquired the infection from another case through human-to-human transmission," World Health Organisation regional director for the Eastern Mediterranean Ala Alwan said in Cairo.

Saudi Arabia has fired Health Minister Abdullah al-Rabiah.

Saudi Arabia has fired Health Minister Abdullah al-Rabiah. Photo: Reuters

"The majority of these secondary cases have been infected within the healthcare setting and are mainly healthcare workers, although several patients are also considered to have been infected with MERS-CoV while in hospital for other reasons."

It took more than two years to reach the first 100 cases of MERS, said Michael Osterholm, director of the Centre for Infectious Disease Research and Policy at the University of Minnesota.

"Now, in just the past two weeks, we've had 100 cases … There's a major change occurring that cannot just be attributed to better case detection," he said. "When humans readily transmit to humans, that's what will cause a worldwide outbreak. We are very concerned that … with what we've seen over the past two weeks … we may be at that point now."

Saudi Arabia is expected to receive a surge of Muslim pilgrims in July during the annual fasting month of Ramadan, followed by millions more in early October for the Haj. But instead of openly stepping up its infection-control procedures and announcing other public health measures, Saudi Arabia has fired its Health Minister Abdullah al-Rabiah.

Adel Fakieh, the Minister of Labour who is now acting Health Minister, this week promised "transparency and to promptly provide the media and society with the information needed" on the virus after visiting the Jeddah hospital where the latest cluster of cases occurred.

MERS belongs to the coronavirus family that includes both the common cold and SARS (severe acute respiratory syndrome) that killed more than 800 people in a global outbreak in 2003. Its symptoms can include fever, breathing problems, pneumonia and kidney failure, experts say.

A lack of "basic epidemiological detective work" meant the biology of the virus, how it is transmitted and whether there is a seasonal element to its spread, had yet to be confirmed, warned Laurie Garrett, a senior fellow for global health at the Council on Foreign Relations.

A recent study said the virus has been "extraordinarily common" in camels for at least 20 years, indicating it may have been passed from camels to humans, but even this hypothesis left many unanswered questions, Ms Garrett said. "You have to be able to explain why all those people in the camel racing business and the camel auctioning and breeding business are not infected.

"Camel milk is a staple in Saudi Arabia - millions of people drink the milk throughout the Emirates and the Persian Gulf - and yet we do not see MERS in the kind of numbers you'd expect from that kind of exposure."

Given the "dramatic surge in infections in the past six days", it is time for Saudi Arabia to do more than just sack its health minister, she said, and start taking the steps that really do save lives, starting with much more aggressive infection control procedures in its hospitals.