Alarm soared in west Africa on Sunday over the deadliest ever Ebola virus outbreak, with an American doctor contracting the disease in Liberia and the death of the first victim from Sierra Leone's capital Freetown.
Samaritan's Purse, a Christian charity, said Dr. Kent Brantly was quarantined at the group's Ebola treatment centre at the ELWA hospital in the Liberian capital Monrovia after falling ill while treating sufferers of the disease, which is deadly in up to 90 percent of cases.
"We remain optimistic for his recovery, but certainly he is not out of the woods," said spokeswoman Melissa Strickland.
His symptoms include intermittent fever and body aches.
In a statement announcing the Ebola case on Saturday, the organization said that Brantly was married with two children.
"Samaritan's Purse is committed to doing everything possible to help Dr. Brantly during this time of crisis. We ask everyone to please pray for him and his family," it added.
The US State Department said it was aware of an Ebola case but could not provide information about a private individual.
An Ebola epidemic has killed at least 660 people in four west African countries since the start of the year, according to statistics from the World Health Organization.
On Saturday, a woman suffering from the first confirmed case of Ebola in Sierra Leone's capital died after her parents forcibly took her from hospital, the health ministry in Freetown said.
Saudatu Koroma, a 32-year-old trainee hairdresser, was admitted to a clinic on July 23 and tested positive for the disease, which has already killed more than 200 people in the west African country.
"Her father and mother forcefully took her away from the hospital" two days later, health ministry spokesperson Sidi Yahya Tunis told AFP.
'Barely able to speak'
Koroma's disappearance prompted Freetown authorities to broadcast a nationwide radio and television campaign, which eventually persuaded her to return for treatment, Tunis said.
Koroma died on Saturday while on her way to an Ebola treatment center in the country's east.
"She was severely dehydrated and weak and could hardly speak," Tunis said. "Blood samples taken from both the father and mother are now being tested."
The house where the dead woman had lived in the east of Freetown has been quarantined with the other residents for 21 days.
Koroma was the first confirmed case of Ebola to reach Freetown in what has become the deadliest ever outbreak of the virus.
Sierra Leone's health ministry said an Ebola treatment centre has been established at Lakka Hospital and health staff have been trained to handle the disease. Surveillance has been increased and people have been asked to report all suspected cases to health authorities, it added.
An AFP journalist in Freetown said people were calm and going about their normal business on Sunday.
Freetown's first Ebola case comes after the incurable disease was confirmed to have reached Lagos in Nigeria, Africa's biggest city.
The health ministry said on Friday that a 40-year-old Liberian man died at a private hospital from the disease, after collapsing at Lagos international airport.
Nigerian carrier Arik said on Sunday it was halting direct flights to Liberia and Sierra Leone, which have seen close to 350 deaths from Ebola between them.
"As a result of the first Ebola virus death officially confirmed in Lagos... Arik Air will be suspending operations into Monrovia and Freetown effective July 28, 2014," an airline statement said. "This decision is a precautionary measure aimed at safeguarding the precious lives of Nigerians."
Ebola can fell victims within days, causing severe fever and muscle pain, vomiting, diarrhoea and, in some cases, organ failure and unstoppable bleeding.
The highly contagious and often fatal disease spreads among humans via bodily fluids, including sweat, meaning one can get sick from touching an infected person.
With no vaccine, patients believed to have caught the virus must be isolated to prevent further contagion.