THE INVISIBLE KILLERS IN OUR WATER

Why ‘Brain-Eating’ Amoebae Are Emerging as a New Climate-Age Health Threat

They live silently in soil and water, invisible to the naked eye—yet a handful of these microscopic organisms can be deadly. Free-living amoebae, often sensationally called brain-eating amoebae, are rapidly emerging as a global public health concern, and scientists are now pointing to climate change and crumbling water systems as the key drivers behind their growing threat.

A new study published in the journal Biocontaminant warns that rising temperatures, ageing water infrastructure and weak monitoring systems are creating ideal conditions for these organisms to flourish—both in natural water bodies and in treated water supplies once considered safe.

“What makes these amoebae particularly dangerous is their resilience,” says Longfei Shu of Sun Yat-sen University, China, the study’s corresponding author. Unlike most microbes, these organisms can withstand extreme heat, survive strong disinfectants like chlorine, and persist inside water distribution systems.

Amoebae are single-celled organisms commonly found in soil and freshwater. While the vast majority are harmless, a few species are capable of causing severe and often fatal infections in humans.

The most notorious among them is Naegleria fowleri, which causes a rare but deadly brain infection when contaminated water enters the nose—usually during swimming or other recreational water activities. In India, recent deaths linked to the amoeba in Kerala have heightened public anxiety and brought renewed attention to the risk.

The study highlights another, less obvious threat: amoebae can act as hidden shelters for other disease-causing microbes. By hosting bacteria and viruses inside their cells, they protect these pathogens from standard disinfection processes, allowing them to survive longer in drinking water systems.

This so-called “Trojan horse” effect may also contribute to the spread of antibiotic resistance, making infections harder to treat and control.

As global temperatures rise, researchers warn that heat-loving amoebae could expand into regions where they were once rare or absent. Several recent outbreaks linked to recreational water use across different countries have already underscored how climate change is reshaping infectious disease patterns.

To confront this growing threat, scientists are urging governments and health agencies to adopt a One Health approach—a framework that connects human health, environmental protection and water management.

The study recommends stronger surveillance systems, improved diagnostic tools and advanced water treatment technologies to detect and neutralise these organisms before infections occur.

“Amoebae don’t belong to just one sector,” Shu notes. “They exist at the intersection of environmental and human health. Addressing them effectively requires coordinated solutions that tackle the problem at its source.”

As warming waters become the new normal, experts warn that what we cannot see may soon become one of the most dangerous challenges lurking in our water.