FREETOWN, Sierra Leone (AP) -- A third top doctor has died from Ebola in Sierra Leone, a government official said Wednesday, as a leading American health official warned that the outbreak sweeping West Africa would get worse.
The disease has already killed more than 1,400 people in Guinea, Liberia, Nigeria and Sierra Leone, and Doctors Without Borders warned that the tremendous influx of patients in Liberia, in particular, is overwhelming their treatment centers there.
"I wish I didn't have to say this, but it is going get worse before it gets better," Dr. Tom Frieden, the director of the U.S. Centers for Disease Control and Prevention, said of the outbreak at the end of a visit to Liberia, where he described the situation as dire.
Liberia has recorded the highest number of cases and deaths of any of the four countries. Doctors Without Borders said in a statement that a new treatment center recently opened in the country's capital with 120 beds filled up almost immediately.
The tremendous number of patients means that the medical charity is not able to provide those patients with intravenous treatments, a primary way doctors keep people who are losing a tremendous amount of fluid alive.
The group did not mention Frieden's visit or recent U.N. ones, but it said discussions happening now about international coordination are coming too late and that there are countries that could make a dramatic difference if they provided more expertise and resources. It did not name the countries.
"This is not only an Ebola outbreak -- it is a humanitarian emergency, and it needs a full-scale humanitarian response," Lindis Hurum, the group's emergency coordinator in Monrovia, the Liberian capital, said in the statement.
Frieden travels next to Sierra Leone, where the loss of a third senior doctor has raised concerns about the country's ability to fight the outbreak.
Dr. Sahr Rogers had been working at a hospital in the eastern town of Kenema when he contracted Ebola, Sierra Leonean presidential adviser Ibrahim Ben Kargbo said Wednesday.
Rogers' death marks yet another setback for Sierra Leone, a country still recovering from years of civil war, where there are only two doctors per 100,000 people, according to WHO. By comparison, there are 245 doctors per 100,000 in the United States.
Health workers have been especially vulnerable because of their close proximity to patients, who can spread the virus through bodily fluids. WHO has said that at least 240 health workers have been infected in this outbreak, more than in any other. One of those is an epidemiologist working with the WHO in Sierra Leone, who has been evacuated for treatment in Germany.
"The international surge of health workers is extremely important and if something happens, if health workers get infected and it scares off other international health workers from coming, we will be in dire straits," said Christy Feig, director of WHO communications.
A team of two experts was sent Tuesday to investigate how the Senegalese epidemiologist became infected, said Feig. In the meantime, WHO has pulled out its team from Kailahun, where he was working.
The epidemiologist had been doing surveillance work for the U.N. health agency, said Feig. The position involves coordinating the outbreak response by working with lab experts, health workers and hospitals, but does not normally involve direct treatment of patients.
There is no proven treatment for Ebola, so health workers primarily focus on isolating the sick. But a small number of patients in this outbreak have received an experimental drug called ZMapp.
Health officials in Liberia said two recipients of ZMapp in Liberia -- a Congolese doctor and a Liberian physician's assistant -- have recovered. Both are expected to be discharged from an Ebola treatment center on Friday, said Dr. Moses Massaquoi, a Liberian doctor with the treatment team.
The drug has never been tested in humans, and it is unclear if it is effective. Only a handful of people have received ZMapp in this outbreak, and some have recovered while others have died.
Meanwhile, the World Health Organization said it was notified Tuesday of an unrelated Ebola outbreak in Congo. The agency said Wednesday that 13 of the 24 people sickened there have died.