What events likely led to the outbreak of cholera in haiti?

Haiti suffered a devastating earthquake in January 2010. Subsequently, much infrastructure in Haiti was destroyed, and many residents did not have access to safe drinking water and sanitation. Haiti suffered a devastating cholera outbreak soon after. Cholera is caused by a bacteria: Vibrio cholerae. The disease causes diarrhoea type symptoms. It is thought that the bacteria was introduced to Haiti by Nepalese peacekeepers from the UN. Since there was no safe sanitation, cholera sufferers would have contaminated the water supplies, leading to the spread of the bacteria in drinking water supplies. 

In Haiti, UN workers accidentally introduced cholera.

The UN did not dispose of human waste correctly. This caused cholera to spread to local people.

The situation in Haiti could be improved by screening UN workers for illness, increasing water sanitation, and providing adequate sewage treatment.