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Middle East Respiratory Syndrome Coronavirus (MERS-CoV) in the U.S.

What Is MERS-CoV?

In 2014, the U.S. Centers for Disease Control and Prevention (CDC) announced two cases of MERS-CoV, the Middle East respiratory syndrome coronavirus infection, were diagnosed in the United States. This newly recognized respiratory virus has been causing concern since it was first seen in 2012 in Saudi Arabia because it is related to the SARS (severe acute respiratory syndrome) virus that caused a deadly outbreak in 2003 and involved 800 patients, three continents, and included many secondary contacts and many health-care workers. MERS-CoV appears less likely to be transmitted from person to person than SARS, but it has a higher mortality rate of up to 36%.

MERS-CoV, formerly known as "novel coronavirus" (nCoV) because it had not been found in humans before, was first described in 2012 in Saudi Arabia. More recently, cases have appeared other Middle Eastern countries as well as in Malaysia, Egypt, Europe, the United States and in 2015, in South Korea, in travelers returning from Saudi Arabia. Secondary spread to other contacts or health-care workers has occurred in multiple countries, and at least one secondary case has been identified in the United States in a person who had not travelled to the Arabian Peninsula but was in a business meeting with a returned traveler from Saudi Arabia who later was diagnosed with MERS-CoV. The secondary case was found to have antibodies to MERS, which indicated infection; however, the person was well and did not require any treatment.

What Are the Symptoms of MERS-CoV?

Infection with MERS-CoV causes symptoms that can range from mild to severe respiratory distress, and it causes death in about one-third of cases. Patients typically complain of fevers, cough, and difficulty breathing. Some of those infected go on to develop pneumonia and kidney failure. Diarrhea has been reported in some, particularly those who are already immunosuppressed. The incubation period, or the time between exposure to the virus and development of symptoms, appears to be between three to 14 days. The source of infections is still being determined, but contact with camels (that are also known to be infected) is strongly suspected at this time. The infection has spread from infected people to other people through close contact, probably via droplets spread through coughing, although the exact mechanism of transmission is still being studied.

How Can I Avoid MERS-CoV While Traveling?

The CDC is monitoring the situation and is currently not advising people to avoid travel to the Arabian Peninsula; however, it is advising travelers to that region to monitor their health, wash their hands with soap and water or alcohol gel, avoid touching their mouth and eyes, and avoid contact with sick people while there. Travelers who develop respiratory illnesses or fever should seek medical attention and inform healthcare personnel of ther travel. They should cover their noses and mouths with a tissue when sneexing or coughing, and then discard the tissue. They should also avoid close contact with others and defer further travel until well.

At this time, the risk to the general population seems small as the virus has not spread easily from person to person, and most people who have been infected are people living in countries of the Arabian Peninsula, returning travelers, or their close contacts. Precautions for travelers are described above.

For more information on the travel alert see http://wwwnc.cdc.gov/travel/notices/alert/coronavirus-arabian-peninsula-uk. For more information on MERS-CoV, see http://www.cdc.gov/coronavirus/MERS/faq.html.


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United States. Centers for Disease Control and Prevention. "Middle East Respiratory Syndrome (MERS)." May 17, 2014. <http://www.cdc.gov/coronavirus/MERS/faq.html>.