Case Definitions

Patient Under Investigation (PUI)

A patient under investigation (PUI) is a person with the following characteristics:

Fever (≥38°C, 100.4°F) 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
Close contact2 with a confirmed or probable case of MERS while the case was ill AND
- fever (>100°F) or symptoms of respiratory illness within 14 days following the close contact. (This is a lower threshold than category A.)

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

Confirmed Case

A confirmed case is a person with laboratory confirmation3 of MERS-CoV infection.

Probable Case

A probable case is a PUI with absent or inconclusive4 laboratory results for MERS-CoV infection who is a close contact2 of a laboratory-confirmed MERS-CoV case.

Footnotes

Countries considered in the Arabian Peninsula and neighboring include: Bahrain, Gaza Strip, Iraq, Iran, Israel, Jordan, Kuwait, Lebanon, Oman, Qatar, Saudi Arabia, Syria, the United Arab Emirates (UAE), the West Bank, and Yemen.
Close contact is defined as a) any person who provided care for the patient, including a healthcare worker or family member, or had similarly close physical contact; or b) any person who stayed at the same place (e.g. lived with, visited) as the patient while the patient was ill.
Confirmatory laboratory testing requires a positive PCR on at least two specific genomic targets or a single positive target with sequencing on a second.
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.