Less than a year after being leveled by a 7.0-magnitude earthquake, a still-ravaged Haiti is suffering another blight—cholera. This time, however, the catastrophe can be traced directly to a human source.

Although health workers have yet to confirm the origin of the disease—previously unknown in Haiti—there have been rumors it was introduced by UN peacekeepers from Nepal. Those suspicions have brought a backlash that has left several dead and, paradoxically, slowed efforts to treat the sick and keep the illness from spreading, according to the Christian Science Monitor.

“In Haiti most people believe it came from the Nepalese and that the UN will do its best to hide it,” Haiti’s Christian Aid Director Prospery Raymond told the Sydney Morning Herald Wednesday, after a riot in Port Au Prince. “If it is confirmed to be from them this will be damaging for the UN and their peacekeeping all over the world.”

The Centers for Disease Control and Prevention has narrowed the Haitian cholera bacteria to one strain, indicating it was likely introduced by a single source, according to the Wall Street Journal (subscription may be required). Still, there are no firm indications that the Nepalese unit brought the disease to the county.

Independent samples from near the battalion have not tested positive for cholera, the United Nations told the Journal. The Nepalese unit was suspected because the battalion is located in the Artibonite region where the cholera originated and the strain matches one found in South Asia, including Nepal. The United Nations has also acknowledged sanitation problems at the base, according to the Associated Press.

Regardless of any evidence they might find, though, researchers say it’s unlikely they’ll pinpoint the exact locus of the contamination.

“We may never know where this came from,” CDC head of Haiti response Scott Dowell told the Journal. “People from other countries have come to Haiti for decades.”

In the meantime, humanitarian agencies are begging for an end to rioting in Cap Haitien, Gonaives, and other cities so they can attempt to stanch the cholera spread.

“We call upon all involved in these clearly orchestrated demonstrations to stop immediately…” UN Humanitarian Coordinator Nigel Fisher stated in a press release. “Every day we lose means hospitals go without supplies, patients go untreated and people remain ignorant of the danger they are facing. It is vital that everything possible is done to contain this outbreak in Cap Haitien while we still can—but this is very difficult in the current environment.”

The United Nations has stopped flights carrying soap, medical supplies, and aid workers to Cap Haitien, according to the statement. Similarly, Oxfam suspended a water chlorination project in the area and the World Health Organization stopped medical training after a food warehouse was looted and burned.

Even when humanitarian organizations are able to resume their work, though, there’s reason to believe cholera in Haiti will be persistent for years to come, according to The Guardian. The inability of most people to take the simplest of precautions against the disease—hand washing with soap and drinking only treated water—are among the reasons health officials expect a prolonged battle. Lack of sanitation facilities and a pure dearth of manpower also factor in.

“Simply put, other actors need to get more involved because the needs are far too great to be covered solely by the organizations currently working to prevent and treat cholera,” Stefano Zannini of Doctors Without Borders told the Monitor. “Both the short-term and long-term forecasts indicate that this situation will get worse, possibly far worse, before it gets better.”