USA Louisiana residents warned of brain-eating organism in their water supply

Water warning culprit is Naegleria fowleri, a type of warm-water-loving microorganism, which can work its way into the brain

Naegleria fowleri amoeba under a microscope

Once in the brain, N fowleri quickly eats brain tissue and causes an infection that with few exceptions kills its hosts within two weeks. Photograph: AP

For the third time in a year, Louisiana residents are being cautioned to watch out for a deadly, brain-eating amoeba-like organism in the water supply in part of the state.

Residents in four towns in St John the Baptist Parish – about 12,500 people in total – are being advised to take special precautions when showering and when swimming in nearby lakes, streams and pools that have been filled with tap water.

The culprit of the water warning is a trophozoite called Naegleria fowleri, a type of warm-water-loving microorganism very closely related to an amoeba (it’s most often referred to as an amoeba in scientific literature).

If the organism is inhaled through the nose it can work its way into the brain. Once there, N fowleri quickly eats brain tissue and causes primary amebic meningoencephalitis (PAM), an infection that with few exceptions kills its hosts within two weeks.

While PAM infections are extremely rare in the United States, there’s some concern among experts that the warming waters caused by climate change will increase Naegleria fowleri’s presence in the South, as well as pull the organism out of its southern strongholds and into northern water systems.

“The hotter it gets, the more likely this amoeba will be in our lakes and rivers and streams,” said Dr Jimmy Guidry, Louisiana’s state health officer and medical director. “I’m sure there are other waters systems that have the amoeba that aren’t even looking for it.”

A 4-year-old boy visiting St Bernard Parish, Louisiana from Mississippi was infected and killed by PAM last September. A month later, N fowleri was found in the DeSoto Parish water system, the same parish where two people died from PAM in 2011.

Those incidents prompted Louisiana to rethink how it monitored its water systems. State health officials were trained by the US Centers for Disease Control and Prevention over the last year, and now the state is becoming the first in the nation to regularly test water systems for amoebas and amoeba-like organisms, according to Guidry. The first test results from that program came back on Wednesday. Those tests showed the organism in St John’s Parish, leading to the current warning. Guidry said the organism might be in other parishes as well, but testing all 1,400 of the state’s water systems will take time.

The state is also working on raising the levels of chlorine in several dozen water systems.

“It’s not a public health threat where we need to alarm people, but it’s a serious enough threat that we’re focusing on chlorinating all our water systems,” he said.

Experts are also worried Naegleria fowleri is expanding beyond its usual hotspots in Louisiana to parts of the country where it had previously been too cold for the organism to survive.

There have been 132 cases of PAM caused by N fowleri in the US since 1962, according to the Centers for Disease Control. Only three people are known to have survived the infection. Until recently almost all of those cases have been in the most southern sections of the United States. But over the last decade, there’s been a spate of PAM infections farther north, including two deaths in Minnesota in 2010 and 2012.

Some also believe PAM infections are underdiagnosed, as symptoms can often look similar to those associated with bacterial meningitis. Travis Heggie, an N fowleri expert at Bowling Green State University in Ohio, said increased education about the infection is needed in the medical field in order to accurately assess how prevalent it is.

“Naegleria is common in the environment and it’s killing more people than we realize,” he said. “It’s just not being diagnosed. We’re still in the very early stages of creating awareness about it.”

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