Disease trackers are accustomed to hunting deadly new pathogens in Africa’s jungles and Asia’s megacities. The sand dunes of the Middle East? Not so much. But that’s the birthplace of the latest previously unknown virus to spread globally: Middle East Respiratory Syndrome coronavirus, or MERS-CoV. Exactly where the virus comes from remains a mystery, but camels are thought to be the source of many human infections. And while the number of cases is still relatively small, health officials are concerned about the potential for spread when as many as 1.4 million Muslim pilgrims descend on Saudi Arabia in October for the annual Hajj, the pilgrimage to Mecca and Medina.
MERS first came to light when a 60-year-old Saudi man died with severe pneumonia and kidney failure in Jeddah in June 2012, though a subsequent analysis found two earlier cases in Jordan. As of May 16, the virus had sickened at least 614 people, killing 184 of them. While cases have been reported in the U.S., Europe, Asia and Africa, all have been in people who live in or traveled to the Middle East, or who were exposed to someone who did. The virus appeared to be on the wane until April, when the case count exploded. Contact with camels during the spring, when females wean their young, may have contributed to the surge in new cases, which was amplified by poor infection control in hospitals. Saudi Arabia’s government fired its health minister and sent text messages to its 30 million residents to raise awareness of the virus. The government, which caps the number of pilgrims each year, has also recommended that people above the age of 65, pregnant women and children under the age of 12 not journey to Mecca or Medina this year. Every Muslim who is physically and financially able is expected to make the pilgrimage at least once.
MERS-CoV belongs to the same family of pathogens as the Severe Acute Respiratory Syndrome (SARS) virus, which killed about 800 people worldwide after first appearing in China in 2003. MERS-CoV turned up in three-quarters of samples taken from camels across Saudi Arabia, according to a study published in February. Camel herders and people who visited a camel farm or consumed unpasteurized camel milk have been among those infected. The virus has also been found in bats, suggesting that they may be a natural reservoir. MERS causes fever, cough and shortness of breath, leading in severe cases to respiratory failure, organ failure and death. People with weakened immune systems are more at risk. There’s no vaccine and no specific treatment. While the number of human infections more than doubled in April and May, there’s no evidence the virus has mutated into a more transmissible form, or of sustained human-to-human transmission. Most of the cases where people passed along the disease involve family members or heath-care workers who were exposed.
The World Health Organization has declared a global public health emergency only twice: In 2009 for the H1N1 influenza (swine flu) pandemic, and this May, when it announced that polio has rebounded after almost being eradicated. The protocol for emergency alerts was put in place after the SARS outbreak in 2003, which disrupted travel across the globe. By mid-May, the WHO had met to discuss MERS five times and each time decided against labeling it an emergency, in large part because of its limited transmission between humans. Rather than suggest travel bans or other global measures that could raise anxieties, the agency called on Saudi Arabia to step up basic infection-control measures in hospitals – like having staff members wash their hands between patients — and to carry out studies to figure out where the virus is coming from, how it’s transmitted and who’s at risk. Individual countries posted their own advisories, including signs that went up at many U.S. airports advising travelers to the Arabian Peninsula to take steps to avoid infection.
The Reference Shelf
- Read the World Health Organization’s answers to frequently asked questions on MERS-CoV.
- The U.S. Centers for Disease Control and Prevention has MERS pages for health-care providers and for consumers.
- German virologist Christian Drosten talks about his observations from a trip to Saudi Arabia and his analysis of the virus.
- Stay up to date with infections in Saudi Arabia on the Saudi Health Ministry’s MERS website.
- Read Thomas Abraham’s book, “Twenty-First Century Plague: The Story of SARS.”