Editor’s note: This story was updated on May 22, 2014.
May 5, 2014 -- The deadly respiratory virus known as MERS is now in the U.S. The virus, which first surfaced in Saudi Arabia in 2012, has mostly been found in the Middle East. It is a close cousin of the deadly SARS (severe acute respiratory syndrome) virus that infected more than 8,000 people worldwide in 2003, killing 774.
Unlike SARS, MERS does not appear to spread that easily from person to person, although one case of human-to-human transmission has happened in the U.S. Here are answers to the most frequently asked questions about MERS.
What is MERS?
MERS, or Middle East respiratory syndrome, is an illness caused by a virus called a coronavirus. It is also sometimes referred to as MERS-CoV, for Middle East respiratory syndrome coronavirus.
Coronaviruses are common globally, the CDC says. Five different types can make people sick. They also infect animals.
Although some coronaviruses cause mild to moderate upper respiratory illness, MERS, like SARS, can cause severe illness and death.
What are the symptoms of MERS?
How common is MERS?
To date, 632 cases have been confirmed in 18 countries, according to the most recent figures from the World Health Organization and the CDC. Of those, 193 people have died.
How is it treated?
There is no cure for MERS, but doctors can treat a patient's symptoms.
How is MERS spread? How contagious is it?
Officials say it most often spreads between people who are in close contact. Infected patients, for instance, have spread the virus to health care workers. The virus does not appear to spread easily among people in public settings, such as a shopping mall.
CDC Director Tom Frieden says, “The risk to the general public is extremely low.”
How is MERS spread? How contagious is it?
In addition to Saudi Arabia, MERS has been reported in these countries, according to the WHO and CDC:
- United Arab Emirates
- United Kingdom
Where did this virus come from?
Public health officials believe it came from an animal source but are still doing research. The virus has been found in camels in Qatar, Egypt, and Saudi Arabia. It's also been found in a bat in Saudi Arabia. But officials can't say for sure if camels are the source of the virus. For now, they say that camels, bats, and other animals may play a role in where the virus comes from and how it spreads.
Is there a vaccine?
No vaccine is available.
Is anyone more susceptible to the virus?
The virus is more dangerous for people with pre-existing conditions or problems with their immune systems.
What can travelers do?
The CDC is advising people not to change their travel plans because of MERS. But it does suggest that travelers watch their health, wash their hands often, and avoid people who are sick.
Adults should help young children thoroughly wash their hands. Alcohol-based hand sanitizer is a good substitute if soap and water are not available.
Travelers who recently went to countries where MERS has been found should watch their health when they return. If the typical symptoms -- cough, shortness of breath, and fever -- develop within 14 days of travel to a country that has had MERS cases, travelers should contact their doctor and discuss their recent travel.
What else is known about the first U.S. cases?
The first two were called “travel-associated” cases. The infections happened in Saudi Arabia, not in the U.S. Both cases involved health care workers living and working in Saudi Arabia, then traveling to the U.S. to visit family. The first was in Indiana and the second was in Orlando, FL. Both patients recovered and were released from hospitals.
One CDC-confirmed case of human-to-human transmission has occurred in an Illinois man. He met the Indiana MERS patient twice before the patient was admitted to the hospital. The Illinois man didn’t seek or require medical care. But his blood tests showed he was exposed to the MERS virus because he developed antibodies to fight it.
What is the CDC doing to prevent the spread of MERS in the U.S.?
The CDC has been notifying passengers who traveled with the health care workers. They are also watching health care workers who came in contact with the patients. All 50 of the workers involved with the Indiana patient have tested negative for the virus, says a hospital spokesman at Munster Community Hospital.
The CDC has posted signs alerting workers and travelers to symptoms of the virus.
WebMD News Editor Valarie Basheda contributed to this story.