One of the most dangerous microorganisms on Earth, Naegleria fowleri has a well-earned nickname as the “brain-eating amoeba,” because of the almost 100% fatal infection it causes. And it’s now been found swimming around in the treated drinking water supplied to two towns in Australia.
A public health notice has been issued to towns in the state of Queensland, after testing found this deadly bug swimming in the drinking water supplies for Charleville and Augathella.
“Murweh Shire Council is advising residents and visitors to Charleville and Augathella that Naegleria fowleri, a rare but potentially harmful organism, has recently been detected in the town water supplies,” the community heath notice stated. “This detection follows a comprehensive water quality project commissioned by Queensland Health and undertaken by a Queensland university.”
While Australia has a reputation for being home to some of the most dangerous species on the planet, fatality rate from encounters with most are surprisingly low. This is due to a number of factors, including snake and spider antidotes, and good rescue response services. Facing off against a saltwater crocodile (Crocodylus porosus) is likely to be deadly around 63% of the time, while an estimated 24% of shark bites between 2020 and 2022 were lethal.
Which makes snakes, spiders, “salties” (crocodiles) and sharks a better animal to run into than N. fowleri. This microorganism travels through the nasal passage and breaks through the bony cribriform plate – which separates the nose and the brain – to enter the olfactory bulb. This is a direct line to the brain. There, it shifts into full trophozoite mode (its feeding form) and begins to break down cells.
It’s called the “brain-eating amoeba” for a reason. Once inside the brain, N. fowleri wraps itself around neurons and glial cells and digests them (phagocytosis), and releases enzymes that dissolve cell membranes and connections between cells. This then triggers oxidative stress and cell lysis (exploding of cells), as well as an extreme inflammatory response from immune cells.
This infection, known as primary amoebic meningoencephalitis (PAM), causing severe inflammation and tissue damage as the brain is flooded with white blood cells and cytokines. Ultimately, it rapidly leads to severe meningitis, encephalitis and edema – brain swelling – that causes coma and usually results in death with seven to 10 days.
Studies of tissue taken from patients with PAM have shown that the brain tissue isn’t just injured but totally destroyed, filled with amobae, dead cells and debris from inflammation.
Ultimately, it’s not something you want to encounter – and it’s not endemic to Australia. In the US, the Centers for Disease Control and Prevention (CDC) has reported there have been 167 known cases of PAM between 1962 and 2024. According to the CDC, 97% of cases with the rare but deadly infection prove fatal.
It’s not common to find this microscopic brain destroyer in drinking water, however. N. fowleri is normally at home in warn, untreated freshwater and soil, so most infections are the result of activities like swimming and diving – anything where your head is submerged. N. fowleri can’t survive in saltwater, nor can it infect someone simply by drinking or washing clothes in contaminated water.
“There is minimal risk to the community as long as people don’t allow water to go up their nose when bathing, showering or washing their face,” a Queensland Health spokesperson said of the recent detection. Last week, a Missouri resident was admitted to intensive care after they were infected while water-skiing. A month earlier, a 12-year-old boy was infected and died after swimming in a lake on holiday in South Carolina.
Signs of infection come on fast, and are hard to miss: High fever, severe headache, confusion, fatigue, nausea and vomiting, hallucinations, altered smell and taste, and even seizures – which begin a day after the amoeba’s journey up the nasal passage. And scientists don’t yet know why infection is rare even in areas of high exposure.
And there are treatment options – the antifungal amphotericin B, alongside other medications and interventions such as hypothermia and steroids – but it’s a race against time that, unfortunately, is stacked against us due to how quickly the organism gets to the brain.
It’s still unknown how N. fowleri made its way into the Australian towns’ treated water supply, and this is currently under investigation. The official health advice is to, essentially, keep water well away from your nose.
“Do not allow water to go up your nose when bathing, showering or washing your face,” continued the local government statement adding a list of preventative measures. “Supervise children when bathing, showering and washing their faces to prevent water from going up their nose; don’t allow children to play unsupervised with hoses or sprinklers and teach them not to squirt water up their nose.”
We have questions regarding that last tip …
Nonetheless, infection remains rare but not zero risk; the amoeba is expected to become more prolific and less seasonal due to warming waters as a result of climate change. A recent study found that of the roughly 400 cases identified at the time – with the most occurring in the US, then Pakistan, Mexico, India and Australia – 92% proved fatal.
In April, scientists published a new study that updated our understanding of N. fowleri in the Journal of Infection and Public Health.
