A potentially deadly brain-eating amoeba was discovered in a water system that serves more than 12,500 people, and state officials started flushing the system Thursday.
No illnesses or deaths have been attributed to the amoeba.
The flushing process will take two months, but the water is safe to drink for people in St. John the Baptist Parish, which is in southeast Louisiana, the state Department of Health and Hospitals said. Swimming or diving in freshwater lakes and rivers is the most common way to contract the amoeba, which can cause injury or death if it gets to the brain, usually through nasal passages.
The amoeba is rare. In 2011, a child died after apparently contracting the organism in St. Bernard Parish, a New Orleans suburb.
The water system is located on the east bank of the Mississippi River, which provides drinking water for many communities near it. The system was sampled as part of a state surveillance program launched earlier this month.
Water purification processes usually kill the organism before it gets into drinking water, but health officials say it can seep through pipe cracks underground after the purification process.
Normal purge treatment involves raising chlorine levels in drinking water, which produces a strong odor when water flows out taps in homes and businesses.
St. John the Baptist Parish is an industrial and farming community roughly midway between New Orleans and Baton Rouge.
Officials said the Naegleria fowleri amoeba was found in the water system serving for people in the Reserve, Garyville and Mount Airy communities.