A potentially deadly amoeba has been found in the water supply of a parish outside New Orleans for the second time in two years, officials said. 
 
 Water from St. Bernard Parish, five miles outside of downtown New Orleans, has tested positive for Naegleria fowleri and the Louisiana Department of Health and Hospitals ordered a 60-day chlorine "burn" starting Thursday to ensure the pathogen would be eradicated from the water supply, officials said. 
 
 It remained unclear how prevalent the amoeba was in the water system since the only two positive tests included a sample of untreated water and another sample from a station that may have been contaminated by ground water. The treated water was found to have the recommended amount of chlorine. 
 
 Jacob Groby, quality control chief for St. Bernard Parish Water and Sewer Division, said water was being flushed and retested to see if the amoeba was present anywhere else in the 225-mile water system. 
 
 The water system serves 44,000 people, down from approximately 68,000 before Hurricane Katrina drove out residents in 2005. 
 
 The lowered population post-Katrina and increased use of eco-friendly devices have led to less water being treated for the same water system, Groby said. As a result, water is standing in the pipes for longer and possibly losing some of its chlorination, he said. 
 
 The Naegleria fowleri is a naturally occurring pathogen in freshwater and can be deadly if it enters the body through the nose and makes its way into the brain. It does not harm people if they drink it or if it gets on their skin. 
 
 In 2013, a 4-year-old boy died in the parish after being infected with the amoeba, while playing on a slip-n-slide, health officials said at the time. 
 
 Dr. William Schaffner, an infectious disease expert at Vanderbilt University Medical School, said people in the area should take steps to stay safe, including keeping their pool chlorinated, and stopping children from playing with hoses to stay cool. 
 
 "You don't [want] water up into the nose," Schaffner said. "You can’t get it just by drinking water -- that’s not a problem." 
 
 Editor’s Note: An earlier version of this story incorrectly stated that the water supply for New Orleans was affected. St. Bernard’s Parish has its own water supply. ||||| Naegleria fowleri (commonly referred to as the “brain-eating amoeba” or “brain-eating ameba”), is a free-living microscopic ameba*, (single-celled living organism). It can cause a rare** and devastating infection of the brain called primary amebic meningoencephalitis (PAM). The ameba is commonly found in warm freshwater (e.g. lakes, rivers, and hot springs) and soil. Naegleria fowleri usually infects people when contaminated water enters the body through the nose. Once the ameba enters the nose, it travels to the brain where it causes PAM, which is usually fatal. Infection typically occurs when people go swimming or diving in warm freshwater places, like lakes and rivers. In very rare instances, Naegleria infections may also occur when contaminated water from other sources (such as inadequately chlorinated swimming pool water or heated and contaminated tap water) enters the nose 1-4. You cannot get infected from swallowing water contaminated with Naegleria. 
 
 Top image (from left to right): Computer-generated representation of Naegleria fowleri in its ameboid trophozoite stage, in its flagellated stage, and in its cyst stage. ||||| Breaking News Emails Get breaking news alerts and special reports. The news and stories that matter, delivered weekday mornings. 
 
 / Updated By Maggie Fox 
 
 A deadly waterborne amoeba that can get into the brain and kill has been found again in tap water in the New Orleans area, state health officials said Thursday. 
 
 They’ve found Naegleria fowleri in St. Bernard Parish, a coastal suburb of New Orleans that was devastated 10 years ago by Hurricane Katrina. 
 
 In 2013, the one-celled organism killed a 4-year-old Mississippi boy who likely got it playing on a back yard Slip 'N Slide. Tests showed it was living in under-chlorinated tap water in the system. Officials cleaned and flushed the system at the time, but it’s back, the state Department of Health and Hospitals said. 
 
 “DHH Safe Drinking Water Program staff sampled seven sites along the St. Bernard Parish Water System. Two of the seven sites tested positive for the amoeba,” the department said in a statement. 
 
 "Two of the seven sites tested positive for the amoeba." 
 
 “One positive test was at a site at the water treatment plant before the water was treated. The second positive test occurred at 948 Angela Street, which may have been contaminated by ground water due to a leak at the sampling station. Chlorine levels at the site of the positive sample did meet the 0.5 mg/l requirement.” 
 
 The health department's Olivia Hwang says officials are putting extra chlorine into the water. She said a car hit the sampling station, causing damage and possibly allowing untreated groundwater to leak into the water supply. 
 
 Chlorination kills the amoeba, which can multiply in warm water. It’s often found in lakes and rivers. It killed a Minnesota teenager earlier this month. 
 
 "There are a number of parts of St. Bernard parish that still don’t have the same levels of population since Hurricane Katrina," she said. That means less water gets used. "Use is good because it pushes new water through the system," she added. 
 
 If fresh water is not continually flushed through pipes, the water can sit and become warm and contaminated. 
 
 N. fowleri is usually harmless unless it gets up someone’s nose. It’s not entirely clear how or why, but in rare instances it can attach to one of the nerves that takes smell signals to the brain. There, the amoeba reproduces and the brain swelling and infection that follows is almost always deadly. 
 
 "The Department urges residents to avoid getting water in their noses." 
 
 It doesn’t hurt people who swallow water. 
 
 “Tap water in St. Bernard Parish is safe for residents to drink, but the Department urges residents to avoid getting water in their noses,” Louisiana’s health department said. 
 
 “DHH conducts sampling of public drinking water systems for Naegleria fowleri each summer when temperatures rise. So far, DHH has tested 12 other systems for the ameba and still awaiting lab results for each.” 
 
 The department has some advice for residents while it re-treats the water system:
– Residents in Louisiana's St. Bernard Parish had to deal with a nasty brain-eating amoeba in their water supply last summer—and now the amoeba has made a return appearance. Water in the parish right outside New Orleans has tested positive for Naegleria fowleri, and officials say the state's Department of Health and Hospitals has ordered a "chlorine burn" to purge the system of the possibly fatal pathogen, ABC News reports. Naegleria fowleri can cause a rare, potentially deadly brain infection when contaminated water enters a person's body (usually by water going up the nose, per the CDC) and travels up to the brain. A statement from the state's Department of Health and Hospitals says two of the seven sites it tested came back positive for the amoeba; NBC News notes one of the two positive samples was of untreated water; the other was from a sampling station hit by a car, which may have caused untreated groundwater to leak into the supply. The 225-mile water system that serves the parish used to provide about 68,000 residents with water, but Hurricane Katrina whittled that number down to about 44,000—and because of that decreased population and an increase in ecofriendly water devices, less water is being treated in the same system, which could end up creating the ideal breeding ground for the amoeba, per ABC. "Use is good because it pushes new water through the system," a health department spokeswoman tells NBC. If fresh water isn't continually forced through the pipes, it can lose the chlorine that kills the amoeba and become contaminated. Despite elevated concern from this news, the health department says it's still safe to drink the water—consumers should just take special care not to get it up their noses. (A 12-year-old Florida boy died in 2013 after being infected with the amoeba.)