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Case Definitions

Healthcare providers should be prepared to detect persons at risk for Middle East Respiratory Syndrome Coronavirus (MERS-CoV) infection; this requires clinical judgment as information on modes of transmission of MERS-CoV and clinical presentation of MERS is limited and continues to evolve.

Limited data on the clinical presentation of MERS are available; most published clinical information to date is from critically ill patients. At hospital admission, common signs and symptoms include fever, chills/rigors, headache, non-productive cough, dyspnea, and myalgia. Other symptoms can include sore throat, coryza, sputum production, dizziness, nausea and vomiting, diarrhea, and abdominal pain. Atypical presentations including mild respiratory illness without fever and diarrheal illness preceding development of pneumonia have been reported. Clinical judgment should be used to guide testing of patients for MERS-CoV infection.

Patients should be evaluated for MERS-CoV infection in consultation with the state and local health departments. For more information, see CDC’s Interim Guidance for Health Professionals.

 

Patient Under Investigation (PUI)

A person with the following characteristics should be considered a patient under investigation (PUI):

  1. Fever AND pneumonia or acute respiratory distress syndrome (based on clinical or radiological evidence) AND EITHER:
    • a history of travel from countries in or near the Arabian Peninsula1 within 14 days before symptom onset, OR
    • close contact2 with a symptomatic traveler who developed fever and acute respiratory illness (not necessarily pneumonia) within 14 days after traveling from countries in or near the Arabian Peninsula1 OR
    • a member of a cluster of patients with severe acute respiratory illness (e.g., fever and pneumonia requiring hospitalization) of unknown etiology in which MERS-CoV is being evaluated, in consultation with state and local health departments.
    OR
  2. Fever AND symptoms of respiratory illness (not necessarily pneumonia; e.g. cough, shortness of breath) AND being in a healthcare facility (as a patient, worker, or visitor) within 14 days before symptom onset in a country or territory in or near the Arabian Peninsula in which recent healthcare-associated cases of MERS have been identified3.

 

Confirmed Case

A confirmed case is a person with laboratory confirmation of MERS-CoV infection. Confirmatory laboratory testing requires a positive PCR on at least two specific genomic targets or a single positive target with sequencing on a second.

 

Probable Case

A probable case is a PUI with absent or inconclusive laboratory results for MERS-CoV infection who is a close contact2 of a laboratory-confirmed MERS-CoV case. Examples of laboratory results that may be considered inconclusive include a positive test on a single PCR target, a positive test with an assay that has limited performance data available, or a negative test on an inadequate specimen.

 

Contact Under Investigation of a Confirmed Case of MERS

As part of investigation of confirmed cases, in consultation with a state or local health department, a person with fever or symptoms of respiratory illness within 14 days following close contact2 with a confirmed case of MERS while the case was ill should be evaluated for MERS-CoV infection.

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Footnotes


  1. Countries considered in the Arabian Peninsula and neighboring include: Bahrain; Iraq; Iran; Israel, the West Bank, and Gaza; Jordan; Kuwait; Lebanon; Oman; Qatar; Saudi Arabia; Syria; the United Arab Emirates (UAE); and Yemen.
  2. Close contact is defined as: a)being within approximately 6 feet (2 meters) or within the room or care area for a prolonged period of time (e.g., healthcare personnel, household members) while not wearing recommended personal protective equipment (i.e., gowns, gloves, respirator, eye protection– see Infection Prevention and Control Recommendations; or b) having direct contact with infectious secretions (e.g., being coughed on) while not wearing recommended personal protective equipment (i.e., gowns, gloves, respirator, eye protection – see Infection Prevention and Control Recommendations. Data to inform the definition of close contact are limited. At this time, brief interactions, such as walking by a person, are considered low risk and do not constitute close contact.
  3. As of June 1, 2014, Jordan, Saudi Arabia, UAE; this may change as more information becomes available.

 

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CDC Commentary: Be on the Alert for This Novel Coronavirus

  • CDC Commentary: Be on the Lookout for MERS-CoV
    CDC Commentary: Be on the Lookout for MERS-CoV
    Running Time 5:26 mins
    Date Released 06/23/2014

    CDC's Dr. Susan Gerber provides an update on MERS, including when to evaluate patients, collecting appropriate specimens, and infection control.
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