Infectious disease experts have been worriedly watching a new disease for more than a year and a half now, but it’s a fair bet that most people still haven’t twigged to the existence of the world’s latest infectious threat: MERS.
That may be changing, with new infections popping up recently in Malaysia, Greece, the Philippines, and Egypt. And late last week, the United States became the 16th country to detect a case of MERS, in an American health care worker who has been living and working in Riyadh, Saudi Arabia.
The acronym is short for Middle East respiratory syndrome. The disease is caused by a cousin of SARS, the coronavirus that killed roughly 900 people and crippled hospital systems in China, Hong Kong, Vietnam, and Canada in 2003, knocking billions of dollars out of the world’s economy in the process. Canada’s outbreak occurred in Toronto, where I live; I covered SARS from its alarming beginning through its exhausting end. The information coming out of Saudi Arabia is limited, and it’s hard to be sure from a distance, but there appear to be many similarities between how the MERS outbreak is playing out in Saudi hospitals and what happened in Toronto during SARS. We are lucky that to this point MERS doesn’t seem to spread as easily as SARS did, though SARS didn’t spread particularly well either, and it still caused major trouble.
As the name suggests, this new disease has been mostly found in the Middle East, in countries such as Qatar, the United Arab Emirates, Jordan, and most especially Saudi Arabia, which has reported 431 cases and 117 deaths, about 80 percent of known infections. All cases to date link back to seven countries in the Middle East.
But one of the curious things about this new disease is that although cases appear to be concentrated in mainly a handful of countries, the virus itself is much more widespread. Evidence of the MERS coronavirus has been found over a wide swath of territory in dromedary camels, the beasts strongly suspected of passing this virus to people. Camels showing signs of previous infection with the virus have been found as far afield as Spain’s Canary Islands, off the northeastern coast of Africa; Tunisia; Ethiopia; Nigeria; and Kenya.
SARS exploded into the human population, seeding itself in hospitals in several parts of the world before it even had a name. But MERS has been doing a slow burn. The new virus was first identified in June 2012 by an Egyptian doctor working in Saudi Arabia and scientists in a Dutch laboratory he turned to for help. But it was only brought to the world’s attention a few months later, in September 2012, when a gravely ill man from Qatar checked into a London hospital. The virus had ravaged the Qatari man’s lungs; he never recovered, dying after nine months in the hospital.
The early deaths—following devastating illness—spooked public health officials and scientists observing the evolving situation. “Don’t become infected with this virus,” a public health officer familiar with one of the first cases told me more than a year ago. “It is not kind to humans.”
Most of the earliest patients succumbed to their infections, but in the past year some mild and even symptom-free cases have been detected. Still, at this point nearly 30 percent of people who have been diagnosed with MERS did not survive. That’s a staggering percentage for any disease, especially a respiratory one that seems to spread via the mechanisms colds and flu viruses use—though fortunately not as efficiently as those human-adapted viruses spread. SARS, by comparison, killed about 11 percent of those infected.
The recent milder cases support the hunch experts have long held—that the true ratio of fatal cases is lower because until now doctors in the main have only ordered MERS testing on people seriously ill with pneumonia. In fact the ratio has been dropping, from more than 50 percent early on to 28.5 percent, an estimate issued this week by the European Centre for Disease Prevention and Control. Epidemiologically, MERS is probably like an iceberg, with the severe cases making up the visible tip. But as none of the affected countries have been testing broadly to see how many people have been infected, it’s impossible at this point to even guess at how much lower the real death rate might be.
It’s one of many unanswered questions about MERS. Another—and currently more pressing—is what is behind the extraordinary surge of cases over the past five weeks? The cumulative global case count more than doubled last month. Saudi Arabia alone has reported upward of 250 cases since the beginning of April; prior to that, only 207 cases had ever been reported globally.