WHO: Ebola death toll reaches 4,877

Ebola is now believed to have killed 4,877 people globally and that the spread of the lethal virus remains "persistent and widespread" in West Africa, the World Health Organization said Wednesday.

In a new update, WHO also said there have been 9,936 probable, suspected and confirmed cases of Ebola, mostly in Guinea, Sierra Leone and Liberia. It said transmission remains "intense" in the capital cities and that cases continue to be underreported.

WHO said two districts in Guinea reported an Ebola case for the first time in the last week. One region is on the border with Ivory Coast and the other is on a major trade route with Mali. All but one of Liberia's 15 districts have now reported at least one Ebola case, but the virus is spreading quickest in Monrovia, with 305 probable, suspect and confirmed cases reported this week.

In Sierra Leone, WHO said that two districts where Ebola had appeared to be slowing — Kenema and Kailahun — have both seen a resurgence of the virus.

WHO reported that 443 health workers have now been infected with Ebola, killing 244. It said "exhaustive efforts" are being taken to get protective equipment for them.

WHO noted a lack of available beds in Ebola clinics is forcing many families to care for sick relatives at home, risking further spread of the virus. Liberia had the worst bed shortage, with only 23 percent of patients hospitalized in a clinic. WHO estimated 4,388 beds are still needed in West Africa.

The agency said basic clinics, where potential patients can be isolated but often not treated, are being set up "as a remedial measure."

WHO also noted that Spain and the U.S. continue to monitor potential contacts of Ebola patients.