(CNN) -- For the first time, a health care worker for a World Health Organization partner organization has fallen ill from Ebola, WHO told CNN on Sunday.
The health worker, a man from Senegal, is in Sierra Leone and receiving care, the WHO said. He's an epidemiologist working for the Global Outbreak Alert and Response Network, which was established by WHO and other partners to respond to international public health emergencies. No further details were given immediately.
"This is the first time someone working under the aegis of WHO has fallen ill with #Ebola," reported WHO via its verified Twitter account. Added WHO spokesman Gregory Hartl via Twitter: "No @WHO worker has been infected with #Ebola. The epidemiologist is from a #GOARN partner."
When asked how the worker contracted the virus, a WHO spokesperson said officials don't yet know all the details.
Separately, a British citizen infected with the virus in Sierra Leone is being flown home, the British Department of Health announced Sunday.
The man, identified simply as William, lives in the West African nation in a home established by an American university for researchers.
He is a volunteer nurse in Kenema Government Hospital, where he was working with Ebola patients, according to Dr. Robert Garry of Tulane University.
Garry is manager of the university's program that researches Ebola. The hospital is run by the government of Sierra Leone, but receives support from Tulane researchers.
The UK government said a specially equipped C17 Royal Air Force plane would transport the patient, who would be transferred to an isolation unit at the Royal Free London NHS Foundation Trust.
"UK hospitals have a proven record of dealing with imported infectious diseases and this patient will be isolated and will receive the best care possible," said deputy chief medical officer John Watson in a press release.
Meanwhile, the Democratic Republic of the Congo reported that two of eight people from the town of Gera suffering from a hemorrhagic fever tested positive for Ebola, a government spokesperson told CNN. The government has set up a lab, mobile treatment center and quarantine area in Gera, which is 1,200 kilometers (750 miles)from Kinshasa.
The strain of Ebola is different from the one in West Africa, government spokesperson Lambert Mende Omalanga said.
Confirmation testing will likely be done by WHO on Monday, said WHO spokesman Hartl via Twitter.
Ivory Coast announced Saturday that it's closing its borders in response to the Ebola outbreak in West Africa.
Prime Minister Daniel Duncan signed the order that closes the land borders Ivory Coast shares with Guinea and Liberia.
The borders will remain closed until further notice in an effort to prevent the Ebola virus from spreading into its territory, according to the government statement.
Ebola is one of the world's most virulent diseases, according to the WHO.
The virus is introduced to human populations through the human handling of infected animals -- like fruit bats, gorillas and monkeys, to name a few -- found sick or dying in the rainforest.
The infection is then transmitted among humans through direct contact with the blood or other bodily fluids of infected people.
WHO's maps of confirmed cases show the Ebola outbreak is limited to four West African nations -- Liberia, Sierra Leone, Guinea and Nigeria. So far, nearly 2,500 suspected cases have been reported in what the WHO says is the worst known outbreak of the disease.
However, the WHO's website says the survival rate for people with Ebola in this outbreak has been 47%, which is a substantial improvement over the disease's survival rate, historically.
CNN's Katia Hetter, Aliza Kassim and Carma Hassan contributed to this report.