Middle East respiratory syndrome (MERS) is a viral respiratory disease caused by a novel coronavirus that was first identified in Saudi Arabia in 2012. The novel coronavirus was named as Middle East respiratory syndrome coronavirus, or MERS‐CoV.
Coronaviruses are a large family of viruses that can cause diseases ranging from the common cold to Severe Acute Respiratory Syndrome (SARS).
Since 2012, 2494 laboratory-confirmed cases of MERS-Cov infection with 858 deaths were reported from 27 countries including Algeria, Austria, Bahrain, China, Egypt, France, Germany, Greece, Islamic Republic of Iran, Italy, Jordan, Kuwait, Lebanon, Malaysia, the Netherlands, Oman, Philippines, Qatar, Republic of Korea, Kingdom of Saudi Arabia, Thailand, Tunisia, Turkey, United Arab Emirates, United Kingdom, United States, and Yemen.
About 80% of human cases were reported in Saudi Arabia. Investigations showed that people get infected there through unprotected contact with infected dromedary camels or infected people. Cases identified outside the Middle East are usually traveling people who were infected in the Middle East and then travelled to areas outside the Middle East.
The clinical presentation of MERS-CoV infection may be asymptomatic showing no symptoms or may show mild respiratory symptoms to severe acute respiratory disease and death.
Typical symptoms of MERS-CoV disease are
Disease can be more serious in older people, people with weakened immune systems, and those with chronic diseases such as renal disease, cancer, chronic lung disease, and diabetes.
Mortality rate among laboratory-confirmed cases was about 35%.
MERS-CoV is a zoonotic virus, which means virus can be transmitted between animals and people. Humans have got infection with MERS-CoV through direct or indirect contact with infected dromedary camels. Dromedary camels are the major reservoir host for MERS-CoV and an animal source of infection in humans. It is believed that in past the virus may have originated in bats and then transmitted to camels.
However, more information is needed to figure out the possible role that camels and other animals may play in transmission of MERS-CoV.
Transmission of Infection:
Non-human to human transmission: Strains of MERS-CoV identical to human strains have been isolated from dromedaries in several countries, including Egypt, Oman, Qatar, and Saudi Arabia. But the route of transmission from animals to humans is not fully understood.
Human-to-human transmission: The virus passes from human to human with close contact such as providing unprotected care to an infected patient, among patients and family members.
MERS-CoV, like other coronaviruses, is thought to spread from an infected person’s respiratory secretions, such as through coughing.
There are two tests to detect MERS-CoV infection.
Molecular Tests-Real-time reverse-transcription polymerase chain reaction (rRT-PCR)-These tests are used to detect active infection (presence of MERS-CoV) in people who are thought to infected with MERS-CoV based on their clinical symptoms and having links to places where MERS-CoV has been reported.
Serology Tests-These tests are used to detect previous infection in people who may have been exposed to the virus, by detecting antibodies to MERS-CoV. (Antibodies are proteins produced by the body’s immune system to attack and kill viruses, bacteria, and other microbes during infection). The presence of antibodies to MERS-CoV indicates that a person had been previously infected with the virus. Serology tests are used for surveillance or investigational purposes and not for diagnostic purposes.
Treatment is supportive and based on the patient’s clinical condition. Severe illness can result into respiratory failure that requires mechanical ventilation and support in an intensive care unit.
No vaccine or specific treatment is currently available, however several MERS-CoV specific vaccines and treatments are in development.
Take everyday preventive actions to protect from respiratory illnesses: