Due to its respiratory presentation, Middle East Respiratory Syndrome (MERS) is often misdiagnosed as community acquired pneumonia or other common viral illnesses like influenza
BY ASSOC PROF DR TAN TOH LEONG
AND DR EVELYN CHAU YI WEN
To date, more than 700 million people worldwide have contracted Covid-19. Within the family of coronaviruses, there are three notable diseases: Severe Acute Respiratory Syndrome (SARS), Coronavirus Disease – 2019 (Covid-19) and Middle East Respiratory Syndrome (MERS). Among these three diseases, MERS has been reported to have the highest worldwide mortality rate of 34.4 per cent, followed by SARS-CoV2 (9.5 per cent) and Covid-19 (2.13 per cent).
What is MERS?
MERS was first reported in Saudi Arabia in September 2012. It is caused by a virus called Middle East Respiratory Syndrome Coronavirus (MERS-CoV) which is one of the seven known coronaviruses, four of which are common and typically only cause mild respiratory symptoms. However, the other three coronaviruses, namely SARS-CoV, MERS-CoV and SARS-CoV-2, triggered global health crises in 2002, 2012 and 2019, respectively.
Who is at risk?
The source of MERS-CoV remains unknown. Individuals at risk of MERS have direct and indirect exposure to dromedary camels in the Middle East, Africa and South Asia. Examples include individuals who, within 14 days, have had direct contact with dromedary camels or have consumed or been exposed to dromedary camel products (such as raw meat, unpasteurized milk or urine) in countries where MERS is known to be circulating in dromedary camels.
MERS does not usually transmit from person-to-person unless there is close contact within the same household or health care personnel providing care to a patient without proper infection control measures.
What are the symptoms?
The presentation of MERS ranges from asymptomatic infection and mild respiratory symptoms to acute respiratory distress, multi-organ failure, septic shock and even death. The incubation period is between two and 14 days. Like SARS and Covid-19, the initial symptoms of MERS are usually non-specific, including cough, sore throat, body ache, low-grade fever, headache and chills.
Some individuals may also experience gastrointestinal symptoms such as nausea, vomiting and diarrhoea. Severe cases and higher mortality rates are common in older populations, immunocompromised individuals and those with chronic diseases such as lung disease, diabetes mellitus and heart disease. Up to 50 per cent of symptomatic adult patients have required ICU admission, with 40-70 per cent requiring mechanical ventilation within the first week.
Due to its respiratory presentation, MERS is often misdiagnosed as community-acquired pneumonia or other common viral illnesses like influenza. Therefore, a high index of suspicion is needed, particularly when there is a travel history to the Middle East and contact with dromedary camels.
This is crucial as additional infection control measures need to be upgraded. Diagnosis is based on clinical symptoms, travel history and laboratory tests (such as molecular detection, serology tests or viral culture).
Prevention and treatment
Currently, there is no specific treatment for MERS. The mainstay of therapy is symptomatic and supportive treatment. While antiviral drugs like ribavirin, human immunodeficiency virus protease inhibitors like lopinavir and ritonavir and pegylated interferon (IFN)—α2a have been used, there is no definitive cure.
Prevention is better than cure. General precaution and personal hygiene measures should be practised when visiting farms or fields where dromedary camels are present. Avoid consumption of undercooked animal products like milk and meat.
Seek medical consultation immediately if any symptoms develop after visiting MERS-related countries, having close physical contact with MERS-infected individuals while ill, or contacting dromedary camels. – The Health
Assoc Prof Dr Tan Toh Leong is an Emergency Medicine Physician and Medical lecturer with the Department of Emergency Medicine, Faculty of Medicine, Universiti Kebangsaan Malaysia (UKM) and President & Founder of Malaysian Sepsis Alliance (MySepsis), while Dr Evelyn Chau Yi Wen is Lecturer and Emergency Physician, UKM Medical Center, UKM and member of MySepsis.