It looks like U.N. peacekeepers might be responsible for the cholera outbreak in Haiti that’s killed at least 442 people so far. Last week, hundreds of Haitians protested the peacekeepers, saying that the Nepalese U.N. base on the infected Arbonite River was the source of the outbreak. The U.S. Centers for Disease Control and Prevention say the protesters might be right: The strain matches strains in Southeast Asia. John Mekalanos, a cholera expert at Harvard University, says the strain is uncharacteristic of Haiti and the Caribbean, and the Nepalese soldiers may have brought the disease to Haiti after an outbreak in Nepal. However, the CDC says it’s impossible to pinpoint the source exactly, and that doing so isn’t as important as fighting the outbreak. U.N. peacekeepers have been stationed in Haiti since 2004, and some leaders have been using the cholera outbreak to inflame anti-U.N. sentiment.