Middle East respiratory syndrome coronavirus, commonly known as MERS, was first reported to health authorities in 2012. Prior to this, MERS had not been known to the medical community, so very little was known about the origins, transmission and severity of the illness.
It was discovered that MERS was caused by a virus, specifically, a coronavirus. There are a number of coronaviruses that are commonly found throughout the world, causing mild to moderate illnesses in people, and some can also be found in different species of animals. It is believed that the MERS coronavirus originated in animals, specifically camels, and evolved to spread to humans.
Since the illness was reported in 2012, the World Health Organization has reported that there have been 2,458 laboratory-confirmed cases of infection with MERS and 848 MERS-associated deaths, with cases reported in 27 countries. To date, all cases of MERS have been linked through travel or individuals living in countries in or near the Arabian Peninsula.
In the United States, there have only been two confirmed cases of MERS, both in May 2014, and both patients lived and worked in Saudi Arabia. MERS is closely monitored globally and currently represents a very low risk to the general public in the United States.
The MERS virus is thought to be transmitted through infected individuals’ respiratory secretions (coughing or sneezing) to close contacts, such as through caring for or living with an MERS-infected person. The exact method by which the virus spreads is unknown, but unlike illnesses such as the flu or the common cold, MERS doesn’t seem to spread easily among people in communities. Instead, MERS has spread mostly among people who are in close contact with or providing direct care for an infected person.
The incubation period, or time between being exposed to the MERS coronavirus and symptoms, is thought to be about five to six days but could range from two to 14 days. The symptoms of an MERS infection can range from mild to severe, including a fever with or without chills and stiffness, a cough, shortness of breath, a sore throat, muscle pain and soreness, vomiting and diarrhea. Some cases of MERS could have more severe symptoms of fever and cough that can progress to pneumonia, which could lead to respiratory failure, kidney damage and even death. Three or four out of every 10, or about 30% of patients reported with MERS, have died.
There is no vaccine for MERS or a specific treatment, so prevention is the best way to reduce the risk of infection. There is no reason to change travel plans to regions where MERS is present. The CDC suggests practicing general hygiene precautions such as frequent hand-washing; avoiding touching the eyes, nose and mouth; and avoiding contact with sick people. This is especially important for anyone with diabetes, kidney failure, chronic lung disease or a compromised immune system, as they may be at higher risk for severe MERS. If someone is at high risk for a severe infection, they should avoid contact with camels and not drink raw camel milk or eat undercooked meat, particularly camel meat.
If someone develops a fever and symptoms of a respiratory illness, such as a cough or shortness of breath within 14 days after traveling from countries in or near the Arabian Peninsula, they should call ahead to a doctor or the nearest hospital or emergency department and mention their recent travel. They should stay home from work or school when possible and delay future travel to reduce the chances of spreading an illness to others.