Middle East respiratory syndrome coronavirus (MERS-CoV) is caused by infection with a species belonging to lineage C of the genus Betacoronavirus. It is an emerging cause of severe viral respiratory illness in humans.
People of all ages have been affected by MERS-CoV, although the median age is about 50 years old (range 9 months to 94 years), with a male predominance. Most patients experience severe acute respiratory syndrome requiring hospitalization. More than 2560 laboratory-confirmed cases, including at least 881 deaths, have been reported to the World Health Organization (WHO). The WHO has reported many cases involving patients with chronic underlying medical conditions (hypertension, diabetes mellitus) or immunosuppression (renal transplantation, chronic corticosteroid use). Asymptomatic cases have been reported, mostly among contacts of laboratory-confirmed cases.
Patients who have recently traveled to the Middle East and have unexplained fever and/or symptoms of a lower respiratory illness, including cough, dyspnea, weakness and fatigue, within 14 days of travel should be investigated for MERS-CoV. Less frequent symptoms may include gastrointestinal symptoms such as abdominal pain, vomiting, and/or diarrhea.
Cases involving immunocompromised patients, including renal transplantation and chronic corticosteroid use, have been described.
The most common risk factors linked to MERS-CoV include travel to countries in or around the Arabian Peninsula and direct / indirect association with the health care setting. Patient-to-patient nosocomial transmission within the 9-12 day incubation period has been described as a risk factor. Also, close physical contact (including residence or visiting) with people who provide care for ill patients increases risk of infection. Tobacco abuse may be a possible underlying factor.
Data suggest that camels are likely a primary source of human MERS-CoV infection, although the routes of direct or indirect transmission are yet unknown. MERS-CoV is similar to the severe acute respiratory syndrome coronavirus (SARS-CoV) found in bats responsible for the 2003-2004 international pandemic. A novel pneumonia-like coronavirus (severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2]) causing an outbreak in Wuhan City, Hubei Province, China, was reported to the WHO at the end of December 2019. On March 11, 2020, the WHO declared COVID-19 a pandemic.
Epidemiology: In April 2012, a cluster of 30 pneumonia cases and 2 deaths secondary to the novel coronavirus was reported in Jordanian health care workers. In September 2012, the first case of MERS-CoV was reported in a Saudi Arabian businessman with acute pneumonia and renal failure. Two months later, a family case cluster of MERS-CoV infections was reported, with 3 confirmed cases and 1 probable case. Since then, there has been an ongoing risk for human transmission in the Arabian Peninsula. Affected countries in the Middle East include Jordan, Kuwait, Oman, Qatar, Saudi Arabia, United Arab Emirates, and Yemen. There are also laboratory-confirmed cases from Lebanon and Iran. Ill travelers and their close contacts have been reported in France, Italy, United Kingdom, Tunisia, Malaysia, Philippines, Greece, Egypt, Netherlands, Algeria, and the United States.
An outbreak in South Korea over a 2-month period in 2015 was the largest outside of the Middle East, involving 186 cases, including 38 deaths. The index patient had a recent history of travel to 4 countries in the Middle East and was asymptomatic until his return home, where he sought care at 2 clinics and 2 hospitals.
Travel Warnings: Per the Centers for Disease Control and Prevention (CDC), travelers should pay attention to their health during and after a trip to the Arabian Peninsula. Travelers to the countries in or around the Arabian Peninsula, including Bahrain, Iraq, Iran, Israel / Palestinian territories, Jordan, Kuwait, Lebanon, Oman, Qatar, Saudi Arabia, Yemen, and the United Arab Emirates, should see a physician if any of the symptoms are present during or after travel to these areas.
Taxonomy: Prior to its taxonomic label by the International Committee on Taxonomy of Viruses in May 2013, MERS-CoV was described under various names, including human betacoronavirus 2c EMC, human betacoronavirus 2c England-Qatar, human betacoronavirus 2C Jordan-N3, betacoronavirus England 1, and novel coronavirus.