(BY: Liz Szabo, USA TODAY)
The unpredictable Ebola outbreak in West Africa is thwarting health officials' best efforts both to contain the epidemic, as well as test new treatments and vaccines.
The number of new Ebola cases has risen sharply in the West African nation of Guinea, for example, even as researchers wonder if there will be enough patients in neighboring Liberia to test experimental vaccines.
Just a few weeks ago, the number of new Ebola cases was falling in all three West African countries.
The outbreak continues to wind down in Liberia, where doctors are now diagnosing just three to five new cases a week, compared to 300 a week in August, according to the World Health Organization. READ MORE OF THIS STORY