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MERS in the U.S.: Why You'll See More of It

Health officials have reported the second US case of Middle East respiratory syndrome virus, or MERS. Here are six things you need to know.

Health officials reported the second U.S. case of the mysterious new Middle East respiratory syndrome virus, or MERS, on Monday. Like the first case, it’s in a health care worker who traveled from Saudi Arabia.

Here are six things you need to know about MERS:

It’s new.

MERS was first seen in Saudi Arabia in 2012. Since then it has spread to 16 countries, most in the Middle East but also in Europe and Asia and now including the United States. It’s a coronavirus, a distant relative of the SARS — severe acute respiratory syndrome virus — that infected more than 8,000 people around the world and killed 774 before it was stopped in 2004.

You can expect more US cases.

"This is unwelcome, but not unexpected," Centers for Disease Control and Prevention Director Dr. Tom Frieden says. Health officials note that just about any disease is just a plane ride away. But most Americans are at very low risk of ever becoming infected. In 2003, eight SARS cases were confirmed in the U.S., all of them in travelers who were infected overseas and who did not infect anyone else.

It can be deadly.

WHO reports more than 530 confirmed cases and 174 deaths since the virus was identified in 2012. It’s killed between a quarter and a third of victims, which is a very high death rate for an infectious disease. But health experts say as officials look more closely for people infected with MERS they are finding milder cases, which takes the mortality rate down. Most who die have been either elderly or had another illness, such as diabetes or kidney failure. MERS

It doesn’t spread easily.

Health officials have closely studied the known patients, and the people who become infected usually have been in close and prolonged contact. One-fifth of the cases have been among health care workers who were treating patients intensively. There’s been no documented spread on an airplane, for instance. A patient in France who died infected a person who shared his hospital room, and family clusters have been reported from Saudi Arabia.

"We believe that if good infection control precautions are used during healthcare the risk to healthcare workers is also exceedingly low," says Dr. William Schaffner of Vanderbilt University, an infectious diseases expert. That includes wearing masks, gowns and gloves when treating patients.

There’s no treatment.

There’s no vaccine against MERS, although some groups are working on one, and antiviral drugs don’t appear to be of much use against it, either. The CDC has told U.S. hospitals to take strict precautions if someone shows up with symptoms. Patient care is mostly support, such as providing oxygen or breathing care.

No one knows where it came from.

The latest research suggests camels, but many patients have had no known contact with camels. Camel meat or milk might be a source, and the virus can live on surfaces and potentially could spread when people touch an infected surface. SARS was eventually traced to an animal called a civet, often sold in Asian markets as food.

Some health officials say it's possible MERS has been circulating but no one knew what it was because there wasn't a test for it. Many respiratory diseases are never diagnosed.

“While experts do not yet know exactly how this virus is spread, CDC advises Americans to help protect themselves from respiratory illnesses by washing hands often, avoiding close contact with people who are sick, avoiding touching their eyes, nose and/or mouth with unwashed hands, and disinfecting frequently touched surfaces,” the agency advises.