LOS PALMAS, Haiti (AP) — U.N. Secretary-General Ban Ki-moon visited rural Haiti on Monday to help launch a program to improve sanitation and fight the spread of cholera, a disease many Haitians blame U.N. peacekeepers for introducing to the impoverished Caribbean country.

An outbreak of the disease that followed Haiti’s devastating earthquake in 2010 has killed more than 8,500 people and sickened about 700,000. Studies have shown cholera-infected waste likely was inadvertently introduced in one of Haiti’s biggest rivers by troops from Nepal, where the disease is endemic.