For some of the scientists and doctors who helped the world battle the 2003 SARS outbreak, the recent rapid rise in human infections in several Middle Eastern countries caused by a cousin virus is creating a sense of sharp unease.
Cases of Middle Eastern respiratory syndrome — MERS — have shot up markedly in the past month, driven it appears by outbreaks in hospitals or among health-care workers in Jeddah, Saudi Arabia, and in Abu Dhabi, in the United Arab Emirates.
"It does kind of bring flashbacks to SARS when we're seeing more health-care associated infections. Obviously that was a big challenge here in Toronto," says Dr. Kamran Khan, an infectious diseases physician at Toronto's St. Michael's Hospital who specializes in using airline traffic data to predict the international movement of diseases.
In late March the global total of confirmed MERS cases crossed the 200 mark, two years after the first known infections occurred. By late Saturday, the combined global count announced by the World Health Organization and national governments was closing in on 290 cases.
If all are confirmed, it will mean 28 per cent of all MERS cases will have been reported in the last month.
This week has also brought word that an event many dread but see as inevitable has again happened. MERS has spread from the Middle East to other countries.
A nurse who was infected in the UAE travelled home to the Philippines where he and several of his local contacts were promptly put into isolation. And a Malaysian man who went to Mecca to perform Umrah, a Muslim pilgrimage, was infected and died upon his return to Malaysia. Authorities from the Philippines and Malaysia were tracking down people who were on the flights those men took.
Case in Greece
On Saturday, Greece announced it had discovered its first MERS case, in a Greek national who has been living in Jeddah, one of the current MERS hotspots.
Like embers flying off a raging bonfire, these types of travel cases will continue to happen, Khan predicts.
"Just from the standpoint of probabilities, the longer this persists, the likelihood of it showing up in other regions of the globe and causing some of that disruption — that health, that economic disruption — is going to increase."
A viral disease passing from animals to humans through an as yet undefined route. A respiratory illness that can be initially hard to distinguish from other cases of pneumonia, a common diagnosis in hospitals. A disease that, because it's hard to spot, can slip undetected into hospitals, infecting other patients and the health-care workers who care for them. A disease that has the potential to travel.
It's no wonder people who remember SARS are watching MERS closely.
They have been since the start, since scientists announced in September of 2012 that a few months earlier a man in Saudi Arabia had died from an infection caused by a new coronavirus, a cousin of the virus that caused severe acute respiratory syndrome or SARS.
It was later discovered that an outbreak of mysterious pneumonia cases in a hospital in Jordan in April of 2012 was caused by the virus that became known as MERS.
Not enough details
In the intervening months cases have also been found in Qatar, Oman and Kuwait. Yemen recently announced its first case, though it has not yet been confirmed by the WHO. Exported cases have popped up in Britain, France, Germany, Italy and Tunisia; in some of those cases the initial patient infected one or two others locally.
Mounting research has shown that camels can be infected with the virus and may even be its natural host. But how a camel virus is being passed to people isn't yet clear. Nor is it known what portion of infections is contracted from animals and what percentage involves person-to-person spread.
It is thought that person-to-person transmission remains limited, dying out after a generation or two. But the information available outside the affected countries is limited, making it hard to gauge whether that is still the case.
In particular, Saudi Arabia has been parsimonious about the amount of detail it provides to the WHO and the scientific community. It has announced roughly 40 cases from Jeddah this month alone — six on Saturday — but has offered limited information about what local media reports have classified as a hospital outbreak.
Local media have reported doctors quitting rather than running the risk of contracting MERS. A sizable number of the Jeddah cases have been health-care workers.
The Saudi government has said there have been cases in five hospitals in the city, which is close to the holy site of Mecca. But it has downplayed the significance of what is happening there, urging people to ignore rumours on social media platforms.
SARS doctor helps Saudi Arabia
Dr. Allison McGeer fought SARS and caught SARS during the large outbreak that crippled Toronto hospitals in the spring and early summer of 2003. She travelled to Saudi Arabia last spring to help investigate an earlier MERS hospital outbreak, in Al Ahsa.
McGeer is keeping a close eye on the MERS situation, but says she can't tell what is happening with the information that is being shared.
"I'm really torn between whether this is an indication of change" — in the virus — " or whether this is just that the disease is in fact seasonal ... and whether we're just seeing the result of more introductions (into hospitals) resulting in more spread in hospitals," admits McGeer, who is head of infection control at Toronto's Mount Sinai Hospital.
"Maybe what happened in Jeddah is a super-spreader," she notes, referring to people who infect a large number of secondary cases.
"Maybe some unfortunate co-incidence of things happened in that emergency department in which there was transmission to a sizable number of people. Could be.... (Or) could be the beginning of a new humanized virus. Without data, it's impossible to tell."
With Ramadan — the Muslim month of fasting — set to start in late June, the number of international and Saudi pilgrims travelling to Mecca to perform Umrah will rise over the coming weeks, Khan notes. And the increase in cases in UAE also give him pause. (The country has reported 36 cases, but 16 of them have been in April.)
"Certainly the concern from my perspective is if you see more cases in a place like UAE, which is a very, very large international hub of travel."
"In some ways it reminds me of Guangzhou and Hong Kong," he says. Guangzhou is the capital of China's Guangdong province, which is where SARS is believed to have started.
"As SARS started to move towards Hong Kong, that's where we saw a lot of that international dispersion. And as the geographic range here continues to expand, there are more opportunities for it to translocate to other geographies."
Most of the international spread of SARS can be traced to a February 2003 event in a Hong Kong hotel, where a dying Chinese doctor unknowingly infected fellow guests who brought the virus to Vietnam, Toronto, Vancouver and Singapore, sparking a global outbreak that took months to extinguish.Suggest a correction