Deaths from the cholera epidemic that ravaged Haiti after the 2010 earthquake could be much higher than the 9,200 officially tallied so far because of underreporting during the initial outbreak, a new study suggests.

The study, by Doctors Without Borders, found that incomplete surveillance and data collection, overwhelmed health clinics, the rapid spread of the disease and cholera’s ability to kill quickly contributed to what appears to have been a drastic understating of the death toll.

Haiti was still deeply traumatized from the January 2010 quake when it was hit 10 months later by the cholera epidemic. Studies have traced the outbreak to faulty sanitation practices by a United Nations peacekeeping force.

It was the first time in a century that Haiti, the Western Hemisphere’s poorest country, was infected with cholera, which spreads through water contaminated by feces. Victims die from severe diarrhea and dehydration.