Middle East respiratory syndrome coronavirus (MERS-CoV)

Overview

Middle East Respiratory Syndrome (MERS) is a viral respiratory disease caused by the Middle East Respiratory Syndrome Coronavirus (MERS-CoV), a novel coronavirus which causes acute respiratory illness in infected patients.

Disease epidemiology

MERS-CoV was first reported by the World Health Organization (WHO) on 22 September 2012. Till date, MERS-CoV infection has been reported in at least 27 countries, with the majority of cases reported in the Middle East region.

There have been no reported cases of MERS in Singapore, but the possibility of an imported case here cannot be ruled out given today’s globalised travel patterns.

Pathogen(s)

Middle East respiratory syndrome coronavirus.

Transmission

MERS-CoV is present in infected dromedary camels and can be transmitted to humans through contact with infected animals or consumption or exposure to contaminated animal products. MERS-CoV may also spread through close contact with infected persons.

Person-to-person transmission is possible, and limited transmission has occurred among close contacts of confirmed cases in household and healthcare settings. There has been no evidence of sustained community spread and transmission of the virus from person to person had occurred mainly in healthcare settings.

Incubation period: 1 to 14 days.

Infectious period: Duration for infectiousness for MERS-CoV is unknown. Respiratory secretions from MERS-CoV patients have been shown to contain viable virus up to 4 weeks after symptom onset. Viral RNA can also be detected on hospital environmental surfaces for up to 5 days following last positive polymerase chain reaction (PCR) from patients’ respiratory sample.

Clinical features

Typical symptoms include fever, cough, and shortness of breath which may progress to severe pneumonia and acute respiratory distress syndrome, requiring intensive care and intubation. Some have reported gastrointestinal symptoms, including diarrhoea and vomiting. There have also been reports of MERS cases presenting as mild respiratory illness and as an asymptomatic infection. Individuals with comorbidities, such as diabetes mellitus, cardiovascular disease, renal disease and immunosuppression, may be at increased risk of severe disease.

Risk factors

Risk factors include:

• Travel to or residence in the Middle East

• Contact with infected dromedary camels in the Middle East, or consumption or exposure to their contaminated products (e.g., raw meat, unpasteurised milk, urine)

• Close contact with a confirmed or suspect case of MERS, while the case was ill

• Exposure in a healthcare facility with an outbreak

Diagnosis

Detection of MERS-CoV in respiratory specimens including sputum, endotracheal aspirate, bronchoalveolar lavage, nasopharyngeal and oropharyngeal specimens through PCR, sequencing or virus isolation.

Treatment and management

There is no curative treatment for MERS. Patients with MERS are managed with symptomatic treatment and supportive care.

Precaution, prevention, and control

Isolation measures

Suspect MERS patients seen at the outpatient settings should be isolated or segregated from the other patients in the clinic, where possible, and be given a surgical mask to wear if experiencing respiratory symptoms prior to the transfer to an airborne infection isolation room (AIIR) in the hospital.

All suspect or confirmed MERS patients should be isolated in AIIRs. Standard, contact and airborne precautions are recommended when attending to suspect or confirmed MERS patients. Full PPE (gown, gloves, eye protection, and N95 mask) is required when treating suspect or confirmed MERS patients.

Contact management

In the case of exposure to an infected person, exposed persons should immediately seek advice from an Infectious Diseases physician and report the exposure to the Ministry of Health.

Close contacts will be contact traced by the Communicable Diseases Agency and appropriately followed up (e.g., quarantine, phone surveillance or self-monitoring).

Vaccination

There is currently no commercially available vaccine for MERS.

Notification

MERS-CoV is a legally notifiable disease in Singapore.

Who should notify:

• Medical practitioners

• Laboratories

When to notify:

• Medical practitioners – on clinical suspicion

• Laboratories – on laboratory confirmation

How to notify:

• Please refer to the Infectious Disease Notification for more information.

Notification timeline:

• Immediately. No later than 24 hours.

Resources

Please refer to the Weekly Infectious Diseases Bulletin for the number of MERS cases in Singapore.

For more information on MERS, please refer to the WHO website.

For general travel advisory, please refer to Health Advice for Travellers.