The virus took its time crossing the Atlantic. And when the first patient suffering from Middle East respiratory syndrome (MERS) finally did turn up in the U.S., he made his way, improbably, to Munster, Ind., population 23,413. A week later a second appeared, flying from the Kingdom of Saudi Arabia to the home of the Magic Kingdom—Orlando, Fla. Both men are doctors who work in Saudi hospitals, the best places in the world right now to avoid if you do not want to catch what is officially known as the MERS coronavirus (MERS-CoV). For both, their travel involved multiple legs—two flights plus an intercity bus for the Indiana patient and four flights for the Florida patient—to get to their destinations, sharing the air with several hundred fellow passengers along the way.



The Indiana man has recovered; the man in Florida remains in the hospital and is said to be improving. Aided by counterparts at Public Health England who are tracing travelers on Saudi Arabia–to-London flights, state and federal public health staffs in the U.S. have spent untold hours identifying people with whom the men came in contact and testing dozens of health care workers, family members and friends. Fingers crossed, there have been no reports that they passed the virus to others in their travels.



But although these cases appear to be crises averted, the World Health Organization (WHO) has warned that incidents like these will continue to occur, in the U.S. and elsewhere. Enormous resources go into ensuring that these episodes remain isolated and that local spread, if it begins, is snuffed out before it can lead to wider outbreaks. Martin Cetron, director of the Division of Global Migration and Quarantine at the U.S. Centers for Disease Control and Prevention, calls the task massive. “We're talking about hundreds of person-hours. Maybe actually thousands of person-hours…. So yes, it's a big deal." And infectious diseases experts warn that one of these times, some place may not be so lucky.



The U.S., the Netherlands, Malaysia, the Philippines, Egypt, Jordan, Greece—all these countries have detected imported MERS coronavirus infections in the past six weeks. (Jordan has had homegrown cases, too; indeed, it is where the first known MERS infections occurred in April 2012.) Turkey and Indonesia would have had to deal with MERS importations as well, but their infected citizens, who had traveled to Saudi Arabia as religious pilgrims, were hospitalized before they could board flights home.



After two years of mainly playing the homebody, sticking close to its apparent Arabian Peninsula roots, MERS-CoV suddenly seems to be spreading its wings. At the end of March, the world had seen only 207 MERS cases in total, 163 of them in Saudi Arabia. By April 27, that number had doubled. It is now on the cusp of tripling. Since its April 2012 debut, roughly 600 people in 19 countries have been diagnosed with MERS. At least 175 of those patients have died, a case fatality ratio—30 percent—that gives pause to everyone who calculates it.



Fortunately, so far it seems MERS-CoV is not that easy to catch, especially if you are not in close proximity to dromedary camels—the, or at least a, source of MERS infection—or seeking care in one of the Saudi, Emirati or Jordanian hospitals that have recently seen spread among health care workers and patients. In Saudi Arabia in particular, multiple hospital outbreaks have tossed gasoline on smoldering embers: The country’s case count has soared since the beginning of April to 511 cases and 157 deaths. That is three and a half times as many deaths as Toronto recorded during its 2003 outbreak of MERS-CoV’s cousin, the SARS coronavirus.



The explosion of cases seems to have galvanized some action. King Abdullah dismissed Saudi Arabia’s health minister on April 21, adding acting health minister to the labor minister’s job title. Transparency—which has been a large problem—initially improved, and the new minister was photographed visiting MERS patients in the hospital. But the amount of information released by Saudi Arabia has started to shrink again. And basic scientific studies that WHO has long asked for still have not been started.



This week a so-called Emergency Committee that advises WHO Director General Margaret Chan on the MERS virus met for the fifth time to ponder whether the outbreak should be declared a PHEIC—public health emergency of international concern—under the International Health Regulations. The group expressed heightened concern about the situation, but decided after five hours of discussion that it falls short of a global health crisis.



Keiji Fukuda, WHO’s assistant director general for health security, explains the main reason for the decision is that there is currently no evidence the virus is spreading easily from person to person in the community, in the way that cold or flu viruses do. And analysis of the genetic sequences of viruses from five recent infections suggests there have been no major mutations that might confer increased transmissibility. So although there have been a lot more cases of late, the pattern of infections is the same: occasionally a person contracts the virus through some means that is not yet understood. If he or she ends up in hospital, “suboptimal” infection control practices and overcrowding in some facilities create conditions in which the virus can spread.



Fukuda says the urgency with which the rest of the world views the situation is not lost on MERS-affected countries. That sense of urgency is likely to rise in coming weeks as Ramadan approaches. The Muslim month of fasting, which begins this year on June 28, is one of two high seasons for pilgrimages to Mecca, the faith’s holiest site. The other is during the Hajj, which this year will take place at the beginning of October.



Kamran Khan, whose research focuses on how global air travel affects spread of infectious diseases, worries about the estimated three million pilgrims who typically travel to Saudi Arabia during Ramadan. Of those, India, Bangladesh and Pakistan send large numbers, says the infectious diseases specialist, who works at the Saint Michael’s Hospital Keenan Research Center in Toronto. “From a public health capacity perspective, how effectively would they be able to recognize a case, be able to implement the appropriate infection control precautions within their hospitals? Because if MERS is spreading within Saudi Arabia, imagine it in a hospital in Bangladesh,” Khan says.



These are the types of concerns the world will have to grapple with going forward. There are currently no drugs to cure MERS, and no vaccine to prevent it. If one could be made, it will take years to develop and license. Meanwhile, although Saudi authorities are warning their citizens not to drink unpasteurized camel milk and to wear gloves when caring for the beasts, the ubiquity of the animals, their importance to the region’s economy and their popularity suggest camel-to-person transmission of MERS-CoV will continue to occur.

