The death toll from the world's worst Ebola outbreak on record reached 3,338 people out of 7,178 cases in West Africa as of Sept. 28, the World Health Organization said on Wednesday.
It said the total number of new cases had fallen for a second week, but warned against reading any good news into the figures as they were almost certainly under-reported and there were few signs of the epidemic being brought under control.
"Transmission remains persistent and widespread in Guinea, Liberia and Sierra Leone, with strong evidence of increasing case incidence in several districts," the WHO's update said.
Although the spread of the disease appears to have stabilized in Guinea, where the epidemic originated, "it must be emphasized that in the context of an outbreak of EVD (Ebola virus disease), a stable pattern of transmission is still of grave concern, and could change quickly," it said.
The WHO data, based on figures from ministries of health, showed 710 dead in Guinea, 1,998 in Liberia and 622 in Sierra Leone.
The WHO report said both Guinea and Sierra Leone reported cases in previously uninfected districts bordering Ivory Coast.
In Liberia, there remained "compelling evidence obtained from responders and laboratory staff in the country that there is widespread under-reporting of new cases, and that the situation in Liberia, and in Monrovia in particular, continues to deteriorate."
Two U.S. Navy mobile laboratories had arrived in Liberia and would be operational by Oct. 5, while a Chinese team in Sierra Leone had begun testing up to 20 samples a day in Freetown.
In two other West African countries, Nigeria - where eight people died - and Senegal, there have been no further suspected cases in more than 21 days, the incubation period of the disease. The WHO deems an outbreak is over when two incubation periods have passed.
Last week the U.S. Centers for Disease Control estimated there would be 8,000 cases reported in Liberia and Sierra Leone by Sept. 30, but said the true figure would likely be 21,000 after correcting for under-reporting.