The U.S. case involves a man in Indiana who traveled to Saudi Arabia and returned to the United States through London Heathrow airport to Chicago's O'Hare airport and then to Indiana by bus, the CDC says.
"This is a rapidly evolving situation," Assistant Surgeon General Anne Schuchat, who is also the director of the National Center for Immunization and Respiratory Diseases, said at a Friday news conference. "The introduction of MERS-CoV is another reminder that diseases are just a plane ride away."
The man didn't become ill until he arrived in Indiana. Symptoms can include fever, cough and breathing problems, which can lead to pneumonia and kidney failure. The CDC says the patient is being well cared for, is currently isolated and is in stable condition. He is being treated at Community Hospital in Munster, Ind., where he arrived Monday.
The CDC says the virus has spread from ill people to others through close contact but has not been shown to spread "in a sustained way in communities." MERS belongs to the coronavirus family, which includes the common cold and SARS, or severe acute respiratory syndrome, which caused some 800 deaths globally in 2003.
Ian Lipkin, a professor of epidemiology at the Mailman School of Public Health at Columbia University in New York, said his research suggests that the virus passes from camels to people, though it's unclear whether the virus is transmitted by drinking raw camel milk, eating raw meat or some other route. The first person known to have MERS-CoV owned four camels, he said.
Lipkin said the virus has been present in Middle Eastern camels since at least the 1990s, but it's not clear whether it has recently changed to trigger the outbreaks in people. Camels in the National Zoo in Washington, D.C., are not infected with the virus, he said.
He praised the CDC's handling of the case, and said the likelihood of transmission is "very slight."
Shira Doron, an infectious disease expert and epidemiologist at Tufts Medical Center in Boston, said the virus is similar to the SARS virus, which caused widespread anxiety, but burned out on its own about a decade ago.
"We've been ready for this since 2012," she said. "Obviously, we've been hoping that it doesn't come and SARS never did come to the U.S., but we've been expecting it and been ready."
The fact that the seasonal flu is hanging around longer this year than usual will cut down on any transmission of MERS-CoV, Doron said. Anyone who shows up in an emergency room with a respiratory infection will immediately be given a mask and put in a private room, she said, minimizing exposure of other people in the ER.
Everyone who came into contact with the Indiana patient — on the plane, aboard the bus or in the hospital — are being warned to look for acute respiratory symptoms. No one else has been confirmed to have been infected, but "it's too early to breathe a sigh of relief," Schuchat said. She added that the virus "represents a very low risk to the broad general public." State and federal public health officials are working together to alert those who may have been exposed to the patient.
Indiana Gov. Mike Pence offered reassurance to state residents. "I want to assure every Hoosier that we have deployed the full resources of the Indiana State Department of Health to engage in tracking this case, assessing the risk to the public and working together to prevent the spread of the virus."
Since April 2012, countries with MERS-confirmed cases include France, Italy, Jordan, Kuwait, Malaysia, Oman, Qatar, Saudi Arabia, Tunisia, the United Kingdom and United Arab Emirates.
The CDC says the virus likely came from an animal source. In addition to humans, MERS-CoV has been found in camels in Qatar and a bat in Saudi Arabia. There is no vaccine or specific treatment for this virus yet.
CASES IN COUNTRIES ON OR NEAR THE ARABIAN PENINSULA:
Saudi Arabia: 322 cases (68 deaths)
UAE: 48 cases (7 deaths)
Qatar: 9 cases (5 deaths)
Oman: 4 cases (4 deaths)
Jordan: 4 cases (3 deaths)
Kuwait: 3 cases (1 death)
CASES IN OTHER COUNTRIES:
United States: 1 case (0 deaths)
U.K.: 3 cases (2 deaths)
France: 2 cases (1 death)
Tunisia: 3 cases (1 death)
Italy: 1 case (0 deaths)
Malaysia: 1 case (1 death)
Source: Karen Weintraub and Doug Stanglin, USA TODAY
Contributing: Associated Press; Shari Rudavsky, Indianapolis Star