Distance: This one is tricky but it's worth noting that Guinea is larger than Sierra Leone and Liberia combined. That means the virus has to travel farther to infect more people. That distance may have caused the virus to spread slower here, but this low-intensity epidemic has actually made it harder to convince the population that the crisis is urgent.
Climate: Around November, epidemiologists fretted that road travel would increase once the rainy season ended, causing the virus to jump to new areas. That didn't really happen. Now, however, we are worried the rainy season will overwhelm already weak water supply infrastructure, because fighting Ebola requires large amounts of clean water for decontamination. Floods and stagnant water can also bring cholera, creating the risk of a second epidemic breaking out at the same time.
Funding: In terms of Ebola response funding, Liberia has received the most, followed by Sierra Leone and then Guinea. Until a recent outbreak in Sierra Leone, it seemed the pattern of declining cases also followed the same order: Liberia now with zero cases, then Sierra Leone, and Guinea next.
Fear: In Liberia, cases became so numerous everyone knew someone who had lost dear ones to Ebola. Did that pervasiveness mobilize people to adopt better health practices? In Guinea, case numbers never reached those levels, and that might explain why the public is not as strict on precautions like hand-washing. And how does that explain Sierra Leone's current situation? Is there a threshold beyond which people adopt whatever strategies are needed to survive?