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For further information, see CMDT Part 32-06: Common Viral Respiratory Infections

Key Features

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

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

Clinical Findings

  • 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 (

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

    • Bronchoalveolar lavage fluid

    • Sputum

    • Tracheal aspirates


  • 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



  • Respiratory failure


  • 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 ...

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