BATON ROUGE, La. - Water samples taken earlier this month from the DeSoto Parish Waterworks District No. 1 have tested negative for the rare ameba Naegleria fowleri, meaning increased chlorine levels in the system have controlled the ameba, the Department of Health announced Wednesday.

DeSoto Parish Waterworks District No. 1 was one of two water systems in Louisiana that tested positive for the rare ameba last year. Following a chlorine burn and a state mandate that required the parish to maintain a 1.0 milligram per liter free chlorine residual throughout the system for 60 days, LDH took two water samples from 10 locations along the system in early January. Testing by the federal Centers for Disease Control and Prevention confirmed this week that all 20 samples were negative for the rare ameba, which has killed three people in Louisiana since 2011.

LDH Secretary Kathy Kliebert said, "Our team has worked closely with the leaders from the water system to come up with a plan to protect the system's customers by controlling the ameba.. While the water was always safe to drink, these test results give us confidence that it is safe for all uses."

Assistant Secretary for Public Health JT Lane said, "We are encouraged by these test results, which show that maintaining a certain free chlorine or chloramine residual in water systems can control this ameba and protect families. This is why LDH issued an emergency rule last year that we believe will make the water that we drink, bathe and play in safer."

Out of an abundance of caution, LDH will conduct additional sampling and testing in DeSoto parish later in the year as temperatures grow warmer, making water more inviting for the ameba. LDH still encourages people to take precautions, including using commercially distilled water or tap water that has been boiled and then cooled, when they are using a Neti pot for a sinus rinse.

Later this month, LDH will collect water samples for testing at from St. Bernard parish's water system, which also had positive ameba test results in 2013 and has also been under a LDH mandate to increase the level of chlorine in its system. The Department will send these samples for testing by the CDC and will announce the results of these tests when they are available. Until this time, LDH recommends that St. Bernard parish residents continue to take precautions to avoid getting water deep inside their noses.


In the fall of 2013, LDH announced that testing by the federal Centers for Disease Control and Prevention confirmed the presence of the Naegleria fowleri ameba in the water system in St. Bernard Parish and in Water Works System No. 1 in DeSoto Parish. The St. Bernard confirmation followed testing of various points on St. Bernard Parish's water system after Naegleria fowleri was determined by the CDC to be the cause of the death of a child who visited St. Bernard Parish in the summer of 2013.

LDH officials selected the DeSoto Parish Waterworks District No. 1 water system for testing in September 2013 because the area was the site of one of two 2011 Naegleria fowleri-related deaths in Louisiana. Following the confirmation in September 2013 that St. Bernard Parish's water system tested positive for the ameba, LDH officials tested the water in the DeSoto Parish Waterworks District No. 1 as a precautionary measure.

At the time of the 2011 deaths in DeSoto and St. Bernard parishes, officials could only confirm the presence of the ameba in the homes of the deceased, but not in the water systems. More advanced sampling technology is now available through the CDC. No known additional infections have occurred in DeSoto Parish, as incidences of infection are extremely rare. Exposure to Naegleria fowleri has historically occurred as a result of swimming or diving in warm freshwater lakes and rivers. An infection of Naegleria fowleri cannot occur by drinking water.

In response to the deaths and the positive test results, in November 2013, LDH issued an emergency rule requiring that water systems in the state maintain a higher residual disinfectant level and increase their number of sampling sites by 25 percent. Most drinking water systems in Louisiana will be required to meet this new higher standard by February 1, 2014. LDH also convened a scientific working group to gather as much information and research as it could about how to protect Louisiana families from the ameba.

Free chlorine or chloramine residual at 0.5 milligram per liter or higher will control the ameba, provided the disinfectant is present at that level throughout the water supply system continually.

LDH launched to provide the public with accurate information about the ameba. LDH is also accepting questions from the public for using a form on this Website or via e-mail to

The Louisiana Department of Health strives to protect and promote health statewide and to ensure access to medical, preventive and rehabilitative services for all state citizens. To learn more about LDH, visit For up-to-date health information, news and emergency updates, follow LDH's blog, Twitter account and Facebook.