Editor’s note: This story was updated on July 28, 2015.
May 5, 2014 -- The deadly respiratory virus known as MERS, first identified in 2012 in the Middle East, has resurfaced in Asia.
In this latest outbreak, more than 180 cases and more than 35 deaths have been reported in South Korea as of July 27, along with one case in China and one in Thailand.
The CDC is urging doctors to consider the MERS virus when seeing sick patients in the U.S. who have traveled recently to South Korea or the Middle East.
Even so, public health experts say there is no need to panic, as the infection is hard to catch without close contact.
Here are some commonly asked questions:
What is MERS?
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 the illness? Where is it found?
More than 1,200 cases have been confirmed worldwide to date, according to the CDC, with nearly 450 deaths, for a death rate of 37%.
In all, 25 countries have reported cases since 2012, when MERS was first identified in Saudi Arabia. In the U.S., two people learned they had MERS in 2014. Both had traveled to areas where there were infections. They both recovered.
How is it treated?
There's no cure for it, but doctors can treat someone's symptoms.
How is the virus spread? How contagious is it?
Experts have more to learn about how MERS spreads, but public health 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 doesn't appear to spread easily among people in public settings, such as a shopping mall.
"It's not that easy to transmit," says Peter Hotez, MD, dean of the National School of Tropical Medicine at Baylor College of Medicine. "It requires very close contact. That's why health care workers bear the brunt."
Where did this virus come from?
Public health officials believe it came from an animal but aren't yet sure. The virus has been found in camels in Qatar, Egypt, and Saudi Arabia. It's also been found in a bat in Saudi Arabia. Officials can't say for sure if camels or bats are sources 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. Hotez says several are in development, though.
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 says people shouldn’t 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 wash their hands thoroughly. Alcohol-based hand sanitizer is a good substitute if soap and water aren't available.
People 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 -- show up within 14 days of travel to a country that has had MERS cases, travelers should contact their doctor and discuss their recent trip.
What about wearing a face mask?
Health care workers and anyone taking care of someone who is sick should wear a mask, says Robert Glatter, MD, an emergency doctor at Lenox Hill Hospital. That includes anyone taking care of someone with MERS at home.
As for everyday travelers, "the problem is we don't know enough about how MERS Corona is transmitted to know if a face mask is going to make a difference," Hotez says.