DAKAR, Senegal (AP) -- When will the world's largest and longest Ebola outbreak end? The West African countries of Sierra Leone and Liberia both appear to be on steady paths to ending the epidemic. The wild card is Guinea, where Ebola hasn't burned as hot but remains stubbornly entrenched.
Liberia's last Ebola patient died March 27; it is now counting down the 42 days it must wait to be declared free of Ebola. Meanwhile, Sierra Leone recorded no new infections Wednesday for the second time; on average, it has logged a handful each day in recent days.
A nationwide lockdown indicated there aren't hordes of hidden cases lurking there.
"The battle to get to zero cases is truly on," Ernest Bai Koroma, Sierra Leone's president, said in a radio address on Thursday.
It's more difficult to discern a trend in Guinea. The World Health Organization has called the picture mixed after noting signs of improvement last week.
Doctors Without Borders added 10 new beds to its treatment center in the capital, Conakry, last week to handle more patients. About half of the Donka center's 50 beds were full as of Tuesday night, according to Raphael Delhalle, the group's field coordinator there.
The outbreak in Guinea has followed this undulating pattern for months and is likely to continue, Delhalle said.
In the year since the first cases were identified in Guinea, Ebola has infected more than 25,000 people, the vast majority in West Africa. Of those, around 10,500 have died.
Even though Ebola has spread longest in Guinea, the country has registered by far the fewest cases. That's primarily because Ebola has yet to explode in a major Guinean city, as it did in the capitals of Sierra Leone and Liberia, said Dr. Dan Jernigan of the U.S. Centers for Disease Control and Prevention. It still could, he warned, but more resources are now being focused on Guinea.
Guinea's president recently implemented new measures to fight the outbreak, including mandating safe burials in hot spots and shutting any health center that finds an Ebola case. Ebola is spread through bodily fluids of the sick and dead; burials and clinics are two major sources of infection.
One measure of whether officials are beginning to bring an outbreak under control is how many new infections are in people who were already being monitored as contacts of the sick.
That figure is only at about 50 percent in Guinea, WHO said Wednesday.
WHO said about two-thirds of new cases in Sierra Leone arose in known contacts, a drop from the previous week. Fifteen percent of cases are still being confirmed only after death.
That's a sign that people are still waiting too long to seek care, and Roeland Monasch of UNICEF said there is still some suspicion and lack of education about government health measures in hot spots.
Associated Press writers Clarence Roy-Macaulay in Freetown, Sierra Leone, and Boubacar Diallo in Conakry, Guinea, contributed to this report.