The Centers for Disease Control and Prevention have just confirmed that the first-ever case of Ebola has been diagnosed in the US. The patient had already been placed in isolation because of his symptoms and because he had recently traveled to Liberia, which is experiencing an epidemic, before two tests confirmed the disease.

This patient is the first to be diagnosed outside Africa with the strain that is currently epidemic there, said CDC director Thomas Frieden, during a conference call with reporters. The outbreak has largely been concentrated in three countries: Liberia, Sierra Leone and Guinea, where 6,574 have been sickened and 3,091 have died so far.

"I have no doubt we will control this importation of Ebola so it does not spread widely in this country," Frieden said.

The patient came to the US to visit family members here and stayed with them, said Frieden. People who shared a flight with him are not at risk for developing Ebola, as patients don't spread the disease until they have symptoms. This patient's symptoms developed four days after the flight. Two days later, on September 26, he sought care, and he was admitted to a hospital and placed in isolation on September 28. The patient wasn't hospitalized right away because early Ebola symptoms look a lot like many other diseases, Frieden says.

"Only someone sick can spread the disease," Frieden says. So anyone the patient was in contact with starting on September 20, is being tracked by public health authorities. They'll be tracked for 21 days; after that, if the disease hasn't developed, it won't. That means that people on the flight from Africa with the patient aren't at risk — only a "handful" of people, including the patient's family, have been exposed.

The patient doesn't appear to have been involved in the Ebola response effort, and won't be moved to a different hospital, since any hospital with an isolation ward can do isolation for Ebola, Frieden says. He declined to say how sick the patient was or what treatment he was receiving, citing privacy concerns.

This isn't the first Ebola patient being treated for the disease in the US, or the first case of a hemorrhagic fever being diagnosed here. Four other hemorrhagic fever patients have been treated here, and one in 2007 had Marburg virus, which is very similar to Ebola. Ebola can be controlled through routine hand-washing and by using gloves and other barriers to prevent contact with infectious bodily fluids. Ebola can't be spread through the air; only direct contact with the body fluids of a patient who is showing symptoms will spread the disease.