Parasite Naegleria fowleri, known as the “brain-eating” amoeba
In addition to causing frequently fatal infections, free-living amoebas also serve as hosts for other disease-causing microorganisms, such as bacteria and viruses.
Scientists specializing in environmental and public health warn that a little-known group of microorganisms, free-living amoebasis becoming a significant concern for global health.
In a recent publication in the journal Biocontaminant, researchers highlight how climate change, obsolete water infrastructure and limited monitoring systems contribute to the dissemination and persistence of these potentially deadly pathogens.
Free-living amoebas are single-celled organisms often found in soil and freshwater environments. Although most species are harmless, some are capable of cause serious and often fatal infections in humans. Among the most notable is the Naegleria fowlerisometimes called “brain-eating amoeba“, which can trigger a rare but almost always fatal brain infection when contaminated water enters the nasal passages, usually during sea bathing or other water activities.
According to researchers, one of the most worrying characteristics of these organisms is their extraordinary resilience. “What makes these organisms particularly dangerous is their ability to survive to conditions that kill many other microbes,” said Longfei Shu, corresponding author of the study and researcher at Sun Yat-sen University. Free-living amoebas can tolerate high temperatures, resist common disinfectants like chlorine, and persist in water distribution systems that are widely considered safe.
In addition to the direct impacts on health, amoebas also represent an indirect threat, acting as hosts of other microorganisms disease-causing. The study explains that bacteria and viruses can survive and multiply inside amoebas, protected from water treatment processes. This “Trojan horse” effect not only helps pathogens persist in drinking water systems, but may also play a role in the spread of antibiotic resistance, says .
Climate change is expected to intensify risks. Rising global temperatures will likely expand the geographic distribution of thermotolerant amoebas to regions where they were previously uncommon. In recent years, outbreaks associated with recreational water use have raised alarm in several countries, highlighting the need for greater vigilance.
The authors defend a coordinated “One Health” approach that integrates human health, environmental sciences and water management.
“Amoebas are not just a medical or environmental problem,” Shu said. “They are in intersection of bothand combating them requires integrated solutions that protect public health at its source.”
