A doctor who contracted Ebola in Sierra Leone is expected to be brought to the United States for treatment on Saturday. The arrival of Dr. Martin Salia to the Nebraska Medical Center will end the US being briefly Ebola-free.

A different doctor who worked with Ebola and got infected with the virus while working in West Africa was released from a New York hospital on Tuesday, in what was believed to be the last known case of Ebola in the US. That doctor, Craig Spencer, did not know he was infected when he returned last month to New York—a development that set off a huge debate about quarantines and civil liberties.

Ten people have been treated for Ebola in the US in recent months as the outbreak in West Africa has killed more than 5,000 victims in Sierra Leone, Guinea, and Liberia.

Salia, a 44-year-old general surgeon who lives in Maryland, had been treating patients at Kissy United Methodist Hospital in Freetown. The hospital was shut down Tuesday after Salia tested positive for the virus. Salia will be the 10th person in the US to be treated for Ebola.

As Ars' science editor John Timmer explains, Ebola's "initial victims are typically immune cells, like dendritic cells and macrophages. These cells are often the body's first line of defense against pathogens, and they help alert the immune system. Once infected, these immune cells may start to express immune signaling molecules indiscriminately. This can lead to the fever and malaise that are some of the first symptoms of infection."

The Nebraska Medical Center in Omaha is one of four hospitals in the US that specialize in treating dangerous, infectious diseases.

On Tuesday, a 21-day monitoring period expired for a Maine nurse, Kaci Hickox, who defied quarantine orders in a dispute that highlighted the science, fear, hysteria, and politics surrounding a disease that has no cure but had just arrived to the United States.

For her part, Hickox said her life is now "back to normal."

"I hope that one day we as an American culture can get over this fear and can learn to show compassion instead, and we can continue to listen to the medical experts about Ebola," she said.

Liberian Thomas Duncan was the first and only patient to die in the US from Ebola, on October 8 at Texas Health Presbyterian Hospital.