(UPDATED May 14, 2014) Middle East respiratory syndrome (MERS) is a respiratory illness caused by a coronavirus, usually referred to as the Middle East Respiratory Syndrome Coronavirus, or MERS-CoV. A coronavirus also caused the outbreak of severe acute respiratory syndrome (SARS), which led to almost 800 deaths in 2003.
MERS-CoV was first reported in Saudi Arabia in September 2012. In a press release issued May 2, 2014, the Centers for Disease Control and Prevention (CDC) identified 401 confirmed cases of MERS-CoV infection in 12 countries, with all reported cases originating in the Arabian Peninsula. Most patients developed severe acute respiratory illness, with fever, cough, and shortness of breath, and 93 patients have died. The case fatality rate in symptomatic patients is 30%.
On April 24, 2014, the World Health Organization (WHO) issued a statement indicating, "although camels are suspected to be the primary source of infection for humans, the exact routes of direct or indirect exposure remain unknown. Investigations to identify the source of infection and routes of exposure are still ongoing." (See also a recent article from Emerging Infectious Diseases, "Human Infection With MERS Coronavirus After Exposure to Infected Camels.")
On May 2, 2014, the first confirmed case of MERS-CoV was reported in the United States: A healthcare worker who was working in Saudi Arabia and who traveled back to the United States on April 24 fell ill on April 27, went to an unidentified hospital emergency department in Indiana on April 28, and was admitted to the hospital that same day. On May 2, CDC testing confirmed that the patient had MERS-CoV, and he/she remains in the hospital, in isolation and in stable condition. (See our news story, "First MERS Case Reported in United States.")
A second case was reported in the United States on May 12, 2014, at a Florida hospital, also in a healthcare worker who had traveled to Florida from Saudi Arabia. (See our news story, "Second MERS Case Reported in United States.")
For clinicians practicing in the United States who may have questions, here is the latest guidance, directly from the CDC and the WHO, on MERS-CoV. (Be sure to check the links provided for the most recent information, because this guidance may change rapidly.)
What are the characteristics of patients diagnosed with MERS-CoV and how communicable is the disease?
The average age of patients who have had confirmed MERS-CoV is 51 years, said Anne Schuchat, MD, assistant surgeon general with the US Public Health Service and director of the CDC's National Center for Immunization and Respiratory Diseases, at a CDC press conference held on May 2, 2014, although children as young as 2 years have reportedly had the disease.
The incubation period is from 2 to 14 days, and it is believed that patients are not contagious during the incubation period.
However, when a patient has had MERS-CoV, it has then spread to others who are in close physical contact with the patient. Transmission from infected patients to healthcare personnel has also been observed. Clusters of cases in several countries are currently being investigated.
The April 24, 2014, WHO statement pointed out that a full 75% of the recently reported cases appear to be secondary cases, meaning that the individuals acquired the infection from another infected person. "The majority of these secondary cases are mainly healthcare workers who have been infected within the healthcare setting, although several patients who were in the hospital for other reasons are also considered to have been infected with MERS‐CoV in the hospital. The majority of the infected healthcare workers presented with no or minor symptoms. Only 4 instances of transmission within households have been reported, and no large family cluster has been identified. When human‐to‐human transmission occurred, transmission was not sustained, and to date only 2 possible tertiary cases have been reported."
Which patients in the United States should be evaluated for MERS?
Healthcare professionals should evaluate patients for MERS-CoV infection if they develop fever and symptoms of respiratory illness, such as cough or shortness of breath, within 14 days after traveling from countries in or near the Arabian Peninsula. (These countries and neighboring countries include Bahrain, Iran, Iraq, Israel, Jordan, Kuwait, Lebanon, the Palestinian territories, Oman, Qatar, Saudi Arabia, Syria, the United Arab Emirates, and Yemen.) In addition, evaluate patients with respiratory symptoms and fever who have been in contact with a symptomatic recent traveler from this area.
Here are all the details you need to consider: CDC: Patient Under Investigation.
If a patient presents who needs investigation for MERS-CoV, immediately contact your local/state health department. Health departments will find information from CDC on reporting here: Reporting Patients Under Investigation.
What lab specimens should I collect if I suspect MERS-CoV?
The CDC has developed molecular diagnostics that will accurately identify MERS cases as well as assays to detect MERS-CoV antibodies. MERS-CoV testing kits have been provided to state health departments so that they can test patients under investigation for MERS-CoV infection.
The CDC recommends "collecting multiple specimens from different sites at different times after symptom onset. Lower respiratory specimens are preferred, but collecting nasopharyngeal and oropharyngeal specimens, as well as stool and serum, are strongly recommended, depending upon the length of time between symptom onset and specimen collection. Respiratory specimens should be collected as soon as possible after symptoms begin." For more information, see the CDC's Interim Guidelines for Collecting, Handling, and Testing Clinical Specimens from PUIs for MERS-CoV.
If I suspect a patient may have MERS-CoV, what infection control precautions should be put into place?
Standard, contact, and airborne precautions are recommended for management of hospitalized patients with known or suspected MERS-CoV infection. The complete CDC guidance can be found on the CDC Web site (Interim Infection Prevention and Control Recommendations for Hospitalized Patients with Middle East Respiratory Syndrome Coronavirus (MERS-CoV), but a key recommendation includes placing the patient in an airborne infection isolation room as soon as possible. In addition, provide personal protective equipment for healthcare personnel, including gloves, gowns, eye protection (goggles or face shield), and respiratory protection that is at least as protective as a fit-tested NIOSH-certified disposable N95 filtering facepiece respirator.
Additional, detailed guidance is offered at the following 2 links:
Healthcare Provider Preparedness Checklist for MERS-CoV
Healthcare Facility Preparedness Checklist
Are antiviral drugs or other specific therapies recommended for the treatment of MERS-CoV?
At this time, all treatment is supportive, and antiviral drug therapy is not recommended. No vaccine is currently available.
What should I tell patients who ask whether they may safely travel to countries in the Arabian Peninsula?
At this time, the CDC does not recommend that anyone change their travel plans because of MERS-CoV. You can remind patients that most instances of person-to-person spread have occurred in healthcare workers and other close contacts (such as family members and caregivers) of people sick with MERS. Details on travel can be found here: Travelers Health: MERS in the Arabian Peninsula.
Related Information
Middle East Respiratory Syndrome (MERS): Information for Healthcare Providers
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Cite this: Middle East Respiratory Syndrome Coronavirus (MERS-CoV): The Bottom Line for Clinicians - Medscape - May 04, 2014.
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