The agency also issued a health advisory alerting health care providers about the signs and symptoms of the deadly Middle East respiratory syndrome, citing the potential for transmission from travelers from South Korea, where a MERS outbreak began in May.
Health care providers were also reminded to ask their patients about whether they’ve traveled to South Korea or the Middle East, where the disease emerged in 2012.
The MERS outbreak in South Korea is the largest outside the Middle East since the syndrome was identified three years ago. Since May 20, there have been 122 cases of the respiratory virus and 10 related deaths in South Korea.
The advisory asks providers to isolate suspected patients and test for MERS without delay in patients with travel history to these areas.
There are no known MERS cases in the United States, though two were reported last year. Both patients, who recovered, were health care workers infected while working in Saudi Arabia.
Symptoms include fever, cough and shortness of breath. Pneumonia and diarrhea have also been reported.
Since 2012, more than 1,000 MERS patients have been diagnosed in 25 countries and more than 400 have died. MERS seems to spike in the spring and summer, which could account for the South Korean outbreak.
South Korean health officials say the virus was imported to that nation in May by a man who had traveled to the Middle East.
In an effort to contain the outbreak, South Korean officials have quarantined more than 3,000 people and have closed more than 2,000 schools.
Many of those who fell ill were health care workers who had treated MERS patients, relatives of the patients or pre-existing hospital patients whose health already was compromised.
Last week, the CDC updated its travel information on MERS to say that visitors to South Korea should take precautions to protect themselves against MERS.
Researchers are still trying to understand how the virus is transmitted but say it apparently can spread through close person-to-person contact, such as caring for someone who is infected without using personal protective equipment.
According to the World Health Organization, most cases have been transmitted from animals to humans. Researchers still are studying how this transmission occurs, but believe camels likely are a source.