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Middle East Respiratory Syndrome (MERS)

Reporting Information

Class A

Report a case, suspected case, and/or positive laboratory result immediately via telephone to the local public health department in which the patient resides.  If patient residence is unknown, report immediately via telephone to the local public health department in which the reporting healthcare provider or laboratory is located.  Local public health departments should report immediately via telephone the case, suspected case, and/or a positive laboratory result to the Ohio Department of Health (ODH).

Reporting Form(s) and/or Mechanism

Immediate telephone reporting is required.

The local public health department should enter the case into the Ohio Disease Reporting System (ODRS) within 24 hours after the telephone report.

The Middle East Respiratory Syndrome (MERS) Patient Under Investigation (PUI) Short Form (CDC) is required for completion by the local public health department when following up with cases.  Information collected from the form should be entered into ODRS where fields are available, and the form should be uploaded in the Administration section of ODRS.


MERS-CoV is a novel species of Coronaviridae virus in lineage C of the genus beta-coronavirus.

Case Definition

Patient Under Investigation (PUI)

A person who has both clinical features and an epidemiologic risk factor should be considered a patient under investigation (PUI) based on one of the following scenarios:

  • Fever AND pneumonia or acute respiratory distress syndrome (based on clinical or radiological evidence) 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 (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.


  • 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 identified.


  • Fever OR symptoms of respiratory illness (not necessarily pneumonia; e.g., cough, shortness of breath) AND close contact with a confirmed MERS case while the case was ill.

The above criteria serve as guidance for testing; however, patients should be evaluated and discussed with public health departments on a case-by-case basis if their clinical presentation or exposure history is equivocal (e.g., uncertain history of healthcare exposure).

Laboratory Criteria for Diagnosis

If infection with MERS-CoV is suspected based on current clinical and epidemiological screening criteria recommended by public health authorities, please contact ODH.

CDC recommends that clinicians collect three specimen types (lower respiratory, upper respiratory, and serum) for MERS testing.

ODH Laboratory (ODHL) has the ability to test clinical respiratory and blood specimens using real-time reverse transcription-PCR assay.  "NEGATIVE" test results will be reported within 24 hours.  When a "PRESUMPTIVE POSITIVE" or "EQUIVOCAL" test result is obtained at ODHL, confirmation by CDC is required; however this should not delay the local investigation and response, including the contact investigation.

See also:

Case Classification


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

Close contact is defined as being within approximately 6 feet (2 meters), or within the room or care area, of a confirmed MERS case for a prolonged period of time (such as caring for, living with, visiting, or sharing a healthcare waiting area or room with a confirmed MERS case) while not wearing recommended personal protective equipment (PPE) such as gowns, gloves, NIOSH-certified disposable N95 respirator, eye protection.

Signs and Symptoms

A wide clinical spectrum of MERS-CoV infection has been reported ranging from asymptomatic infection to acute upper respiratory illness and rapidly progressive pneumonitis, respiratory failure, septic shock, and multi-organ failure resulting in death.  In some cases, diarrhea preceded respiratory symptoms.  In general, the first noted symptom may be fever (>100.4°F [>38.0°C]).  Other early symptoms have included headache, chills, myalgia, nausea/vomiting, and diarrhea.


Patients who meet the criteria for a PUI should also be evaluated for common causes of community-acquired pneumonia (e.g., influenza A and B viruses, respiratory syncytial virus, Streptococcus pneumoniae, and Legionella pneumophila).  This evaluation should be based on clinical presentation and epidemiologic and surveillance information.

In the presence of person-to-person transmission of MERS-CoV anywhere in the world, healthcare providers should evaluate patients in the U.S. for MERS-CoV infection if they meet the PUI criteria.

If a patient meets the PUI criteria healthcare providers will need to:

  1. Institute standard, contact, and airborne precautions.
  2. Notify the local health department.
  3. Consider MERS-CoV testing.



MERS-CoV has been found in some camels, and some MERS patients have reported contact with camels.  More information is needed to determine the role camels and other animals may play in transmission of MERS-CoV.

Many people with MERS have had close contact with a person sick with MERS.


Health officials first reported the disease in Saudi Arabia in September 2012. Through retrospective investigations, health officials later identified that the first known cases of MERS occurred in Jordan in April 2012.  So far, all cases of MERS have been linked through travel to, or residence in, countries in and near the Arabian Peninsula.  The largest known outbreak of MERS outside the Arabian Peninsula occurred in the Republic of Korea in 2015.  The outbreak was associated with a traveler returning from the Arabian Peninsula.

MERS represents a low risk to the general public in the United States.  Despite intensive case finding efforts and testing, only two individuals have been diagnosed with MERS in the U.S. (in May 2014) and both returned to the U.S. after travel to Saudi Arabia.

Mode of Transmission

MERS-CoV, like other coronaviruses, is thought to spread from an infected person's respiratory secretions, such as through coughing.  However, the precise ways the virus spreads are not currently well understood.

Person-to-person spread of MERS-CoV, usually after close contact, such as caring for or living with an infected person, has been well documented.  Infected people have spread MERS-CoV to others in healthcare settings, such as hospitals.  Researchers studying MERS have not seen any ongoing spreading of MERS-CoV in the community.

Period of Communicability

Patients can shed the virus after resolution of symptoms, but the duration of infectivity is unknown.  Patients are not contagious during the incubation period.  Asymptomatic cases might not be contagious.

Incubation Period

As a result of investigations, incubation periods for MERS-CoV is estimated to range from 2 to 14 days (median 5 days).

Public Health Management



Healthcare providers/Local health departments should continue to routinely ask about travel history and healthcare facility exposure and consider a diagnosis of MERS-CoV infection in persons who meet the criteria for patient under investigation (PUI).  Please fax to ODH Bureau of Infectious Diseases at (614) 564-2456.


No vaccine or specific treatment for MERS-CoV infection is available; care is supportive.  See the World Health Organization's (WHO) guidance for clinical management of MERS patients.


Ill people who are being evaluated for MERS-CoV infection and do not require hospitalization for medical reasons may be cared for and isolated in their home.  Isolation is defined as the separation or restriction of activities of an ill person with a contagious disease from those who are well.

Guidance on the evaluation of patients for MERS-CoV infection, clinical specimen collection and testing, infection control, and home care and isolation measures is available on CDC's MERS website.

CDC recommends healthcare providers should adhere to recommended infection control measures, including standard, contact, and airborne precautions while managing patients in healthcare settings who are PUIs or confirmed cases of MERS-CoV infection.  See CDC's Updated Guidance on MERS-CoV Infection Control in Healthcare Settings.

Droplet precautions should be added to the standard precautions when providing care to all patients with symptoms of acute respiratory infection.  Contact precautions and eye protection should be added when caring for probable or confirmed cases of MERS-CoV infection.  Airborne precautions should be applied when performing aerosol-generating procedures.

WHO issued new guidelines for management of asymptomatic persons who are RT-PCR positive for Middle East respiratory syndrome coronavirus (MERS-CoV) in January 2018.  Until more is known, asymptomatic RT-PCR positive persons should be isolated, followed up daily for development of any symptoms, and tested at least weekly – or earlier, if symptoms develop – for MERS-CoV.

The place of isolation (hospital or home) shall depend on the healthcare system's isolation bed capacity, its capacity to monitor asymptomatic RT-PCR positive persons daily outside a healthcare setting, and the conditions of the household and its occupants.  See WHO's Management of asymptomatic persons who are RT-PCR positive for Middle East respiratory syndrome coronavirus (MERS-CoV) for additional information.


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

Other contacts of the ill person, such as community contacts or contacts on conveyances (e.g., airplane, bus), may be considered for evaluation in consultation with state and local health departments.

Evaluation and management of close contacts of a PUI should be discussed with state and local health departments.  Close contacts of a PUI should monitor themselves for fever and respiratory illness and seek medical attention if they become ill within 14 days after contact; healthcare providers should consider the possibility of MERS in these contacts.

CDC does not recommend the quarantine of asymptomatic individuals who have had exposure to MERS-CoV; however, asymptomatic contacts are advised to monitor their health (i.e., measure temperature twice daily and respiratory symptoms) for at least 14 days after the last possible contact with an infected person.  During this time, in the absence of both fever and respiratory symptoms, persons who may have been exposed to MERS-CoV patients need not limit their activities outside the home and should not be excluded from work, school, out-of-home child care, church, or other public areas.  They should immediately seek medical attention if they develop symptoms such as fever, respiratory symptoms (including coughing and shortness of breath), or diarrhea.

Close contacts of a confirmed case who are ill and do not require hospitalization for medical reasons may, in consultation with the state and local health department, be cared for and isolated in their home while being evaluated for MERS-CoV infection.

Contacts with no apparent symptoms who test positive by PCR, especially in respiratory specimens or serum, likely pose a low but not no risk of transmission.  Local health departments should contact ODH to discuss home isolation, home quarantine, or other measures for close contacts, patients who test positive, and to discuss criteria for discontinuing these measures.

Additional Resources

CDC: Interim Infection Prevention and Control Recommendations for Hospitalized Patients with Middle East Respiratory Syndrome Coronavirus (MERS-CoV).

United States Food and Drug Administration (2014): Fact Sheet for Healthcare Professionals: Interpreting CDC Novel Coronavirus 2012 Real-time RT-PCR Assay Test Results.

WHO (June 2018): Guidelines for Investigation of Cases of Human Infection with Middle East Respiratory Syndrome Coronavirus (MERS-CoV).


Revised 2/2018. Reviewed 7/2019.