Middle East Respiratory Syndrome–Coronavirus (MERS-CoV)

Essentials of Diagnosis

• Mild, moderate, or severe respiratory illness

• Travel to endemic area, including Saudi Arabia, United Arab Emirates, Qatar, and Jordan, within 14 days before symptom onset

• Contact with camels reported in many cases

• Fever, cough, and dyspnea

• CDC can assist with real-time PCR

• Supportive treatment; mortality 36–45%

General Considerations

• History of residence or travel in the Middle East, in particular Saudi Arabia, or contact with such patients

• Virus is transmitted between humans through direct or indirect contact of mucous membranes with infectious respiratory droplets

• The virus is shed in stool, but the role of fecal-oral transmission is unknown

• Person-to-person transmission can occur within families; hospital-associated cases comprise 10–25% of cases

• Median incubation period is 5 days (range, 2–14) with the mean age of 50 (range 9 months to 99 years) and 65% occurring among men

• Over 90% of patients have an underlying medical condition, including diabetes mellitus (68%), hypertension (34%), or chronic heart or kidney disease

• Persons with diabetes, kidney disease, chronic lung disease, or other immunocompromising conditions likely are at highest risk for severe disease

• Most common symptoms being fever (98%), cough (83%), and dyspnea (72%)

• Chills and rigors are common (87%)

• Gastrointestinal symptoms may occur

  • May precede respiratory symptoms

  • Diarrhea is most common (26%), followed by nausea and abdominal pain

• Mild and asymptomatic cases are reported

Laboratory Findings

• Hematologic findings include

  • Thrombocytopenia (36%)

  • Lymphopenia (34%)

  • Lymphocytosis (11%)

• Moderate elevations in lactate dehydrogenase (49%), AST (15%), and ALT (11%) are recognized

• Serum serologies and RT-PCR are available through CDC (https://www.cdc.gov/coronavirus/mers/lab/index.html)

• Highest viral loads are found in lower respiratory tract specimens, including

  • Bronchoalveolar lavage fluid

  • Sputum

  • Tracheal aspirates

Imaging

• Chest radiograph abnormalities are nearly universal and include

  • Increased bronchovascular markings

  • Patchy infiltrates or consolidations

  • Interstitial changes

  • Opacities (reticular and nodular) and pleural effusions

  • Total lung opacification

• Respiratory support is essential

• No vaccine or known antiviral therapy exists to combat MERS

• Current therapies are adapted from SARS treatments and include

  • Interferons

  • Ribavirin

  • Lopinavir-ritonavir

  • Mycophenolate mofetil

Complications

• Respiratory failure

Prevention

• Isolation and quarantine of cases

• Strict infection control measures are essential as well as care and management of household contacts and hospital workers engaged in the care of patients

• Travelers to Saudi Arabia (including the many pilgrims to the holy sites) should practice frequent hand washing and avoid contact with those who have respiratory symptoms

• Control measures, including quarantining in the home for high-risk exposed persons and the use of facemasks for preventing hospital-acquired infections, are important

• Assisting public health authorities with case reporting and surveillance is essential

• Postexposure prophylaxis with ribavirin and lopinavir/ritonavir for health care workers is associated with a 40% decrease in the risk of acquiring infection

Prognosis

• Overall mortality rate of identified cases is about 36%

• Factors associated with mortality include the use of corticosteroids and the use of continuous renal replacement therapy

• A set of radiographic criteria (diffuse involvement, fibrosing sequela) are associated with a worse prognosis and the need for intubation

• Advanced age is associated with a poor prognosis