LONDON (AP) -- The World Health Organization says the number of Ebola cases in West Africa has gone up for the first time this year and warns the coming rainy season could complicate efforts to contain the disease.
In an update published online Wednesday, the U.N. health agency said there were 124 confirmed cases last week, up from 99 the week before.
WHO said there are continuing problems tracking the virus' spread and that only 21 percent of new cases in Sierra Leone were from known contacts, meaning health officials have no idea how the majority of new patients are being infected. Ebola is also continuing to spread to new areas in Guinea, close to the border with Mali.
To date, the virus is believed to have killed nearly 9,000 people.