The World Health Organization says an outbreak of the Ebola virus has killed more than 500 people in 3 countries in West Africa.
A WHO spokesperson said in Geneva on Friday that there have been 888 confirmed or suspected cases, and 539 deaths.
The outbreak began in Guinea in March. The number of new cases has been declining in Guinea but is growing rapidly in neighboring Liberia and Sierra Leone, raising concerns that the epidemic may spread further.
The aid group Doctors Without Borders has set up an operation center in Kailahun, in east Sierra Leone, where many infections have been reported.
The group says it has treated more than 70 patients during the past 2 weeks and that it has doubled the number of beds to deal with the growing number of cases.
The group is calling on local residents to avoid contact with infected people and to see a doctor immediately if they show symptoms of the disease.
A member of the group says more specialists and other staff are needed and called on the international community to provide further support.
Jul. 12, 2014 - Updated 06:55 UTC