MERS

Middle East respiratory syndrome; first tubercles described in Saudi Arabia in 2013.

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MERS-CoV electron micrograph

Most people confirmed to have MERS-CoV infection have had severe respiratory illness with symptoms of:

• fever
• cough
• shortness of breath
• diarrhea and nausea/vomiting in some

Risk factors

Pre-existing conditions among people who got MERS have included

• diabetes
• cancer
• chronic lung disease
• chronic heart disease
• chronic kidney disease

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SARS-CoV-1 mammals as carriers

Symptom onset

• The symptoms of MERS start to appear about 5 or 6 days after a person is exposed, but can range from 2 to 14 days.
• Some infected people had mild symptoms (such as cold-like symptoms) or no symptoms at all.

Transmission

• MERS-CoV, like other coronaviruses, likely spreads from an infected person’s respiratory secretions, such as through coughing. However, we don’t fully understand the precise ways that it spreads.
• MERS-CoV has spread from ill people to others through close contact, such as caring for or living with an infected person. Infected people have spread MERS-CoV to others in healthcare settings, such as hospitals.
• Researchers studying MERS have not seen any ongoing spreading of MERS-CoV in the community.
• All reported cases have been linked to countries in and near the Arabian Peninsula.
• Most infected people either lived in the Arabian Peninsula or recently traveled from the Arabian Peninsula before they became ill.
• A few people have gotten MERS after having close contact with an infected person who had recently traveled from the Arabian Peninsula.
• The largest known outbreak of MERS outside the Arabian Peninsula occurred in the Republic of Korea in 2015 and was associated with a traveler returning from the Arabian Peninsula.

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MERS-CoV genome organization

Clinical Course

• The median incubation period for secondary cases associated with limited human-to-human transmission is approximately 5 days (range 2-14 days).
• In MERS-CoV patients, the median time from illness onset to hospitalization is approximately 4 days.
• In critically ill patients, the median time from onset to intensive care unit (ICU) admission is approximately 5 days, and median time from onset to death is approximately 12 days.
• In one series of 12 ICU patients, the median duration of mechanical ventilation was 16 days, and median ICU length of stay was 30 days, with 58% mortality at 90 days.
• Radiographic findings may include unilateral or bilateral patchy densities or opacities, interstitial infiltrates, consolidation, and pleural effusions.
• Rapid progression to acute respiratory failure, acute respiratory distress syndrome (ARDS), refractory hypoxemia, and extrapulmonary complications (acute kidney injury requiring renal replacement therapy, hypotension requiring vasopressors, hepatic inflammation, septic shock) has been reported.

Laboratory Findings

• Laboratory findings at admission may include leukopenia, lymphopenia, thrombocytopenia, and elevated lactate dehydrogenase levels.
• Co-infection with other respiratory viruses and a few cases of co-infection with community-acquired bacteria at admission has been reported; nosocomial bacterial and fungal infections have been reported in mechanically-ventilated patients.
• MERS-CoV virus can be detected with higher viral load and longer duration in the lower respiratory tract compared to the upper respiratory tract, and has been detected in feces, serum, and urine.
• Duration of MERS-CoV shedding in the respiratory tract is typically longer in more severely ill patients than mildly ill patients, and evidence of virus has been detected in survivors for a month or more after onset.
• Limited data are available on the duration of extrapulmonary MERS-CoV shedding.

• ==Treatment==
• There is no specific antiviral treatment recommended for MERS-CoV infection.
• Individuals with MERS often receive medical care to help relieve symptoms.
• For severe cases, current treatment includes care to support vital organ functions.

Prevention

You can help reduce your risk of getting respiratory illnesses:

• Wash your hands often with soap and water for at least 20 seconds, and help young children do the same. If soap and water are not available, use an alcohol-based hand sanitizer.
• Cover your nose and mouth with a tissue when you cough or sneeze, then throw the tissue in the trash.
• Avoid touching your eyes, nose, and mouth with unwashed hands.
• Avoid personal contact, such as kissing, or sharing cups or eating utensils, with sick people.
• Clean and disinfect frequently touched surfaces and objects, such as doorknobs.
• If you are caring for or living with a person confirmed to have, or being evaluated for, MERS-CoV infection, see Interim Guidance for Preventing MERS-CoV from Spreading in Homes and Communities.

MERS Resources
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