#45: The Return of Cholera

Before the devastating 2010 earthquake, Haiti did not have a case of cholera for over a century. However, once the earthquake hit, water and sanitation infrastructure was demolished. Cases of cholera began springing up everywhere in the population, becoming a huge problem that only made the situation in Haiti worse. 

It turns out that the resurgence of cholera in Haiti was actually caused by the very people who came in to help. Humanitarian aid workers from the UN arrived in Haiti, and the exact strain of cholera was traced back to the sewage at a UN camp where Nepalese peacekeepers were living.