The United States has quarantined a man who may have exposed fellow passengers and crew on two trans-Atlantic flights to a tuberculosis strain that is extremely hard to treat.
It is first time the US government has issued such an isolation order since 1963, when it took action against a smallpox patient, according to the US Centers for Disease Control and Prevention.
The man, a US citizen from the state of Georgia, is suffering from extensive drug-resistant TB, known as XDR TB, which resists virtually all antibiotics, the CDC said. Tuberculosis is a bacterial infection that usually attacks the lungs.
CDC Director Dr. Julie Gerberding said authorities in the United States and other countries were trying to notify passengers who traveled on Air France flight 385, arriving in Paris from Atlanta on May 13, and on Czech Air flight 0104, arriving in Montreal from Prague on May 24.
The man, whom officials also did not identify, is at Atlanta's Grady Memorial Hospital in respiratory isolation.
He told the Atlanta Journal-Constitution newspaper that he flew into Canada to avoid American authorities after they told him when he was in Italy to turn himself over to officials there due to the seriousness of the disease.
He said he believed he had to return to the US to get the treatment he needed to survive.
Officials at the Centers for Disease Control and Prevention have recommended medical exams for cabin crew members and passengers who sat within two rows of the man.
Dr Gerberding said health authorities were aware of the man's condition before he left the United States and warned him against traveling.
"Under the circumstances, I think we were surprised that the patient had left the country," she said.
The man returned to the United States by car. He voluntarily entered a medical isolation facility in New York City on Friday before being flown on a CDC plane back to Atlanta on Monday. Authorities called him "relatively asymptomatic."
Officials did not say where the man became infected. Gerberding said he must remain isolated until public health officials deem him to be no longer infectious.
Tuberculosis kills about 1.6 million people annually, with the highest number in Africa. It is spread through the air when infectious people cough, sneeze, talk or spit.