Lethal threat lurking in Americas lakes and rivers spreads to new states. Just one swim

Jaysen Carr spent the Fourth of July swimming and riding on a boat at one of South Carolina’s most popular lakes.

Just two weeks later, the 12-year-old was dead, killed by a rare and deadly brain-eating amoeba lurking in the seemingly pristine waters.

Naegleria fowleri, the organism responsible, enters the body through the nose and travels to the brain where it causes swelling, seizures and comas. It kills about 97 percent of patients, with only four out of 168 infected Americans ever surviving the infection.

Following the latest fatality, doctors and Carr’s parents are sounding the alarm, warning that more people may be at risk. 

In recent years, the amoeba has spread beyond its traditional range, traveling from Florida and Texas to Missouri, Indiana and as far north as Minnesota. There are also warnings over the infection in Canada.

Rising temperatures are partly to blame, experts say, warming freshwater lakes, rivers and streams above 77 F (25 C), which creates an ideal environment for the organism to thrive.

‘This is a bug that thrives and lives in soil and water, and can enter the nose when people dive and jump feet first into freshwater,’ Dr Mobeen Rathore, a pediatrician in Florida who has treated several patients with the infection, told the Daily Mail.

‘Unfortunately, the fatality rate is very high, and cases are also associated with the summer because that is when people are more likely to visit freshwater lakes.’

Below, the Daily Mail details what Naegleria fowleri is, where it is in the US and how people can become infected. 

What is Naegleria fowleri?

Naegleria fowleri is a microscopic organism invisible to the human eye that causes a nearly always fatal infection.

It lives in freshwater lakes, rivers and hot springs. In some cases, it has also been detected in poorly maintained swimming pools, splash pads and tap water that contains too little chlorine.

It is not found in the ocean.

The single-celled organism feeds on bacteria in the water, and can enter the human body when water gets into the nose.  

‘Unfortunately, with the violent act of getting that warm freshwater up one’s nose, that amoeba has the ability to enter into the brain… and cause a severe infection,’ said Dr David Sideroski, a pharmacology expert in Florida who has spent a decade researching treatments for amoebas like Naegleria fowleri.

This can cause primary amebic meningoencephalitis (PAM), an infection that destroys brain tissue.

Early warning signs usually start about five days after infection and include a sudden onset of fever, headache, vomiting or a stiff neck.

As the disease progresses, patients may also suffer from confusion, seizures, hallucinations and a coma.

Where is the amoeba in the US?

The amoeba is now considered ubiquitous in any body of freshwater above 77 F (25 C). 

It is particularly likely to be in sediment at the bottom of lakes, rivers and streams, or in shallow areas where the sediment can be easily disturbed, causing the amoeba to be spread to the surface.

Once only known to be in southern states like Texas and Florida, Naegleria fowleri has now been detected as far north as Maryland, Indiana and Minnesota. There are even warnings about the disease in Canada.

‘We should assume that any body of warm freshwater could be contaminated with this pathogen,’ Dr Sideroski said – calling the movement ‘a northern migration’.

The spread is due to rising temperatures, leading more bodies of freshwater to reach prime temperatures allowing the organism to thrive.

How do you get infected?

People become infected with the amoeba after water forcefully enters their nose, normally as the result of jumping into warm water.

In some cases, people have also become infected after cleaning their sinuses with contaminated water or via poorly treated water sprayed by jets at splash pads.

Dr Rathore said there is also a risk – though, an extremely unlikely one – of infection simply from dipping your head underwater while swimming.

‘I always say flamboyantly cannonballing into [water], that is the kind of violent energy that pushes water up the nose,’ Dr Sideroski explained.

‘But there are cases, too, where someone has been playing in a splash pad and caught and died from Naegleria fowleri… and that’s likely due to spraying or rough-housing with your compatriots.’ 

It is possible for Naegleria fowleri to enter the body without causing harm. If the amoeba is swallowed, it is destroyed by stomach acid and poses no risk. Even if it enters the outer part of the nose, it may not reach the brain and therefore may not lead to infection.

Once in the body, Naegleria fowleri travels up the olfactory nerve (the nerve that goes from the nose to the brain) and infects the brain. Once there, it eats nerve cells, causing major inflammation and cerebral edema, or abnormal accumulations of fluid, leading to a headache, coma and then, in almost all cases, death.

How is the disease treated?

As PAM leads to inflammation in the brain and destroys brain tissue, Dr Rathore said patients suspected to be infected must immediately start on treatment, even before the disease is confirmed.

He said drugs used to treat PAM include an anti-fungal medication, an antibiotic and an experimental drug from the CDC that can attack amoebas.

In one case, survivor Kali Hardig had her body cooled to 93 F (33 C) to help preserve undamaged brain tissue.

Dr Rathore said the infection could only be treated ‘with great difficulty’.

All four patients who survived required months of therapy to relearn how to walk, talk and move their bodies. All said they’ve suffered from ongoing injuries.

Sebastian DeLeon, who survived an infection at the age of 16 in 2016, previously revealed that the infection left him needing to relearn how to walk, write and do ‘all the basic stuff’. He said he was still struggling with brain damage.

In another case, Caleb Ziegelbaur, who caught the amoeba in 2022 at the age of 13, has been left with such severe brain damage that he needs to use a wheelchair and can only communicate with facial expressions.

Are cases rising?

The CDC does not indicate whether cases are rising, but does say that the disease is spreading further north, raising the risk that more people are exposed to the pathogen. 

At the time of reporting Naegleria fowleri infections are considered rare, with only 167 recorded over the 60 years documented, from 1962 to 2024.

Most cases have been in young males, typically around 11 to 14 years old, and almost all are linked to recreational activities in warm freshwater bodies of water. In a few cases, infections were linked to exposure to municipal water from faucets or splash pads that contained too little chlorine.

Although cases are rare, death from an infection is not. Naegleria fowleri kills 97 percent of everyone it infects.  

Only four of the documented patients are known to have survived.

How do I avoid an infection? 

Dr Rathore said it only takes one gulp of water up the nose to risk becoming infected with the amoeba.

‘The first line of defense is don’t get into the warm freshwater,’ he said.

‘If you do get in, keep your head out of the water. And if you are going to get your head or nose into the water, pinch it or use a nose clip.’

Pinching your nose and using clips is also recommended by Dr Sideroski.

Dr Rathore also advised people not to dive or cannonball into water because this raises the risk of water entering the nose forcefully and causing the disease.

However, Dr Rathore pointed out that there are very few infections despite an estimated 67 percent of Americans spending time in freshwater and told the Daily Mail even he, who lives in Florida, still enters freshwater himself despite reports of the amoeba.