American diagnosed with Ebola being flown to Bethesda, MD for treatment

© Michael Duff/AP

A healthcare worker prepares a colleague’s Ebola virus protective gear at a clinic operated by the International Medical Corps in Makeni, Sierra Leone.

An American healthcare worker who contracted Ebola while fighting the outbreak in Sierra Leone will be brought to the US for treatment, the National Institutes of Health announced on Thursday.

The healthcare worker is due to arrive at the NIH facility in Bethesda, Maryland, on Friday. The patient, who has not been identified as male or female, was volunteering in an Ebola treatment unit in Sierra Leone.

News of the American's infection came hours after it was announced that the epidemic in west Africa had a grim milestone: more than 10,000 people had died from Ebola in Sierra Leone, Liberia and Guinea, according to numbers released by the World Health Organization. So far, more than 24,000 people in nine countries have been infected.

The countries have made significant gains in the fight against Ebola in recent months, with the overall number of new Ebola cases slowing significantly. Earlier this month, Liberia discharged its last Ebola patient. Just six months earlier, Liberia - which has recorded more than 9,000 cases of Ebola, including more than 4,000 deaths - was reporting 300 new cases a week.

Healthcare workers are at heightened risk of exposure because of their close contact with ill patients. Since the outbreak began in December, 840 health workers have tested positive for Ebola in west Africa; there have been 491 reported deaths.

The individual being flown to the US will be the second Ebola patient to receive treatment at the facility, specifically designed to provide high-level isolation capabilities and staffed by infectious diseases and critical care specialists. The first patient, Dallas nurse Nina Pham, was treated successfully.

Pham is now suing the Dallas hospital where she contracted the disease while caring for Thomas Eric Duncan, who was first person to be diagnosed with Ebola in the US. Duncan, a Liberian national, died in the Dallas hospital in October, after he was initially misdiagnosed and sent home. His relatives settled a lawsuit with the hospital for an undisclosed sum of money.

The NIH facility has also monitored a doctor and a nurse exposed to the Ebola virus. Neither developed the disease.

In total 10 Ebola patients have been treated in the US. Eight patients survived and two have died, including Duncan and Dr Martin Salia, a Sierra Leone national and US resident who died while undergoing treatment in Nebraska.

Also on Thursday, NBC News chief medical editor Nancy Snyderman announced that she will be leaving the network for a teaching position at a US medical school.

In a statement, Snyderman said: "Covering the Ebola epidemic last fall in Liberia, and then becoming part of the story upon my return to the US, contributed to my decision that now is the time to return to academic medicine."

While reporting in Liberia, one of Snyderman's cameramen, Ashoka Mukpo, contracted the Ebola virus. Snyderman was placed under a 21-day quarantine because of her exposure to an Ebola patient. Snyderman was forced to make a public apology when she failed to abide by the conditions of her voluntary quarantine.

Mukpo was transported to an infectious disease facility in Nebraska and successfully treated.