Table 1.

WHO and CDC case definitions for MERS-CoV.

Case definition	WHO	CDC
Confirmed	Nucleic acid testing RT-PCR: 2 specific genomic targets  • upE31  • ORF1a, ORF1b or N gene OR RT-PCR: one specific genomic target and: Sequencing of a second target: nsp12 or M gene	Nucleic acid testing RT-PCR: 2 specific genomic targets  • upE31  • ORF1a, ORF1b or N gene OR RT-PCR: one specific genomic target and: Sequencing of a second target: nsp12 or M gene
	Serology Screening test:  • ELISA  • IFA Confirmation test:  • Neutralization	Serology Screening test:  • ELISA Confirmation test:  • IFA  • Microneutralization Surveillance, investigation Not diagnosis
Probable (WHO) or Patient under investigation (PUI) (CDC)	1. Febrile acute respiratory illness with clinical, radiological, or histopathological evidence of pulmonary parenchymal disease AND Direct epidemiologic link with a laboratory-confirmed MERS-CoV case AND Testing for MERS-CoV is unavailable, negative on a single inadequate specimen or inconclusive	1. Fever AND pneumonia or acute respiratory distress syndrome AND EITHER: history of travel from countries in or near the Arabian Peninsula within 14 days before symptom onset, OR close contact 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 Peninsula, OR a member of a cluster of patients with severe acute respiratory illness of unknown etiology in which MERS-CoV is being evaluated, in consultation with state and local health departments
	2. Febrile acute respiratory illness with clinical, radiological, or histopathological evidence of pulmonary parenchymal disease that cannot be explained fully by any other etiology AND Resides or traveled in the Middle East, or in countries where MERS-CoV is known to be circulating in dromedary camels or where human infections have recently occurred AND Testing for MERS-CoV is inconclusive	2. Fever AND symptoms of respiratory illness (not necessarily pneumonia) 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 identified.
	3. Acute febrile respiratory illness of any severity AND Direct epidemiologic link with a confirmed MERS-CoV case AND Testing for MERS-CoV is inconclusive	3. Fever OR symptoms of respiratory illness (not necessarily pneumonia) AND close contact with a confirmed MERS case while the case was ill.