St. Bernard Parish in Louisiana is undergoing a 60-day chlorine “burn” of its water supply after Naegleria fowleri was detected. (Photo: Getty Images)

A brain-eating amoeba that killed two people in two weeks ago has turned up in the water supply of a Louisiana county near New Orleans for the second time in two years.

The water supply of St. Bernard Parish (Louisiana counties are called parishes), which is located five miles outside of downtown New Orleans, is undergoing a 60-day chlorine “burn” to eradicate Naegleria fowleri, the Louisiana Department of Heath and Hospitals announced.

Officials say the burn is being conducted “out of caution,” adding that the tap water is safe to drink because you cannot become ill by drinking infected water. However, they warn that residents should avoid getting water in their noses because it can infect people via that route. It travels up the nose and into the brain, where it typically causes an infection of the lining around the brain (meningitis) and inflammation of the brain (encephalitis). Symptoms often include severe headaches, fever, and a stiff neck.

Infection with the amoeba is often deadly. A teenage boy died this month after developing an infection believed to have been caused by Naegleria fowleri that he came into contact with while swimming in a lake. Hunter A. Boutain, 14, died from primary amoebic meningoencephalitis (PAM), a rare infection of the brain caused by the amoeba, just 48 hours after he went swimming in Minnesota’s Lake Minnewaska. He was hospitalized after his swim and was unresponsive hours later, The Associated Press reports.

Naegleria fowleri, the amoeba that killed 14-year-old Hunter Boutain. (Photo: Corbis Images)

“Hunter’s condition deteriorated throughout the night and he was declared brain-dead this morning,” his uncle and family spokesman, Brian Boutain, said in a statement to the AP. “Hunter died surrounded by his family. It is a deeply emotional time for all us. We ask for privacy and prayers as we remember our beloved Hunter.”

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The news is eerily similar to a report that surfaced in late June of a 21-year-old woman who died of PAM after swimming in a lake in Reno, Nevada.

The woman, whose identity has not been released by her family, first experienced a headache, nausea, and vomiting on June 16, the Reno Gazette-Journal reports. She was hospitalized and diagnosed with meningitis, before suffering cardiac arrest and dying on June 20. (Tests conducted by the Centers for Disease Control and Prevention were positive for Naegleria fowleri.)

But according to the CDC, Naegleria fowleri infections are extremely rare in the U.S. Just 35 infections were reported from 2005 to 2014 and, of those infections, 31 people were infected after swimming. One contracted the parasite from contaminated water used on a backyard Slip’N Slide.

Despite the rarity of infections, Naegleria is found in freshwater all over the world, says infectious disease specialist Dr. Amesh Adalja, an assistant professor at the University of Pittsburgh Medical Center. And the parasite loves warm water.

“During summer months, you’re going to see cases of Naegleria fowleri infections because people tend to engage in water-related activities,” he explains to Yahoo Health.

Naegleria fowleri doesn’t just show up in lakes, though; it can be in your water as well. Three of the 35 cases reported to the CDC were people who were infected after doing nasal irrigation (such as with a neti pot) with contaminated tap water.

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“If you’re going to use a neti pot, it’s probably not a bad idea to use sterile or filtered water,” says Dr. Steven Gordon, chairman of the infectious disease department at the Cleveland Clinic, which has seen a few cases of Naegleria fowleri infections.

Gordon tells Yahoo Health that experts don’t know why some people become infected with the most deadly form of the infection and others don’t.

But experts do know that it often kills. “Virtually everybody who contracts it dies from it,” says Adalja. However, he says there have been a “handful of cases” where people have survived, after doctors were able control pressure in the patients’ brains.

While experts stress that Naegleria fowleri infection is rare, there are some steps you can take to lower your already slim odds of developing the illness.

If you’re concerned about contracting the infection, avoid putting your head underwater while swimming in lakes or rivers, and don’t jump or dive into freshwater — all of which can result in water getting up your nose. You can also wear nose plugs to keep water out.

However, Gordon says, “It’s such an unusual event … we don’t want you to stop swimming.”

Testing tap water for the amoeba is still relatively new, says the Louisiana Department of Health and Hospitals, and it is evolving. While your drinking water is likely fine, it’s probably not a bad idea to avoid getting tap water up your nose — just to be safe.

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