Middle East Respiratory Syndrome (MERS) is an illness cause by a virus (more specifically, a coronavirus) called Middle East Respiratory Syndrome Coronavirus (MERS-CoV). MERS affects the respiratory system (lungs and breathing tubes). Most MERS patients developed severe acute respiratory illness with symptoms of fever, cough and shortness of breath. About 30% of them died.
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 to countries in and near the Arabian Peninsula. This virus has spread from ill people to others through close contact, such as caring for or living with an infected person. However, there is no evidence of sustained spreading in community settings.
MERS can affect anyone. MERS patients have ranged in age from younger than 1 to 94 years old.
CDC continues to closely monitor the MERS situation globally and work with partners to better understand the risks of this virus, including the source, how it spreads, and how infections might be prevented. CDC recognizes the potential for MERS-CoV to spread further and cause more cases globally and in the U.S. We have provided information for travelers and are working with health departments, hospitals, and other partners to prepare for this.
We don’t know for certain where the virus came from. However, it likely came from an animal source. In addition to humans, MERS-CoV has been found in camels in Qatar, Egypt and Saudi Arabia, and a bat in Saudi Arabia. Camels in a few other countries have also tested positive for antibodies to MERS-CoV, indicating they were previously infected with MERS-CoV or a closely related virus. However, we don’t know whether camels are the source of the virus. More information is needed to identify the possible role that camels, bats, and other animals may play in the transmission of MERS-CoV.
Listen to a 4-minute podcast about Middle East Respiratory Syndrome.
Symptoms & Complications
Most people confirmed to have MERS-CoV infection have had severe acute respiratory illness with symptoms of:
- shortness of breath
Some people also had gastrointestinal symptoms including diarrhea and nausea/vomiting. For many people with MERS, more severe complications followed, such as pneumonia and kidney failure. About 30% of people with MERS died. Most of the people who died had an underlying medical condition. Some infected people had mild symptoms (such as cold-like symptoms) or no symptoms at all; they recovered.
Based on what researchers know so far, people with pre-existing medical conditions (also called comorbidities), may be more likely to become infected with MERS, or have a severe case. Pre-existing conditions from reported cases for which we have information have included diabetes; cancer; and chronic lung, heart, and kidney disease. Individuals with weakened immune systems are also at higher risk for getting MERS or having a severe case.
Based on information we have to date, the incubation period for MERS (time between when a person is exposed to MERS-CoV and when they start to have symptoms) is 2-14 days.
Stay informed about MERS via the CDC.gov