Water looks clean and safe most of the time. People drink it, swim in it, and use it daily without much worry. But how often does anyone think about what might be hiding inside?
Scientists now warn that some dangerous germs survive quietly in water and soil. Climate change is making it easier for these organisms to grow and spread.
A recent article highlights one such threat called free-living amoebae.
Environmental and public health researchers say this group of tiny organisms could become a serious public health risk if action does not happen soon.
What are free-living amoebae?
Free-living amoebae exist all around the world. Poor water systems, rising temperatures, and weak testing methods allow these organisms to grow unnoticed.
Many countries do not track these microbes closely, which makes early detection difficult.
Amoebae are single cell organisms found in natural environments like soil, lakes, rivers, and tap water systems.
A rare but deadly amoeba
Most types cause no harm to humans. However, a few species can lead to severe disease. One well-known example is Naegleria fowleri – often called the brain-eating amoeba.
This amoeba can cause a rare brain infection when contaminated water enters the nose.
Swimming, diving, or using untreated water for nasal cleaning increases the risk.
Once infection begins, survival becomes very unlikely. Although cases remain rare, fatal outcomes raise serious concern among health experts.
Where do the amoebas live?
Free-living amoebae survive in warm water, which makes rising global temperatures an important risk factor.
Hotter weather allows these organisms to expand into new areas where colder conditions once kept growth under control.
These organisms show strong resistance to harsh conditions. Longfei Shu, corresponding author and researcher at Sun Yat-sen University, explains the problem clearly.
“What makes these organisms particularly dangerous is their ability to survive conditions that kill many other microbes,” said Shu.
“They can tolerate high temperatures, strong disinfectants like chlorine, and even live inside water distribution systems that people assume are safe.”
Limits of water treatment
Water treatment systems usually use chlorine to kill germs that can make people sick. This method works well for many bacteria and viruses, but free-living amoebae can survive even after chlorine treatment.
Some types do not just pass through the system but stay inside water pipes and storage tanks. These hidden spaces allow growth over time and make complete removal very hard.
Because these organisms remain inside water systems, people may stay exposed without knowing. Water can look clean, smell normal, and taste fine, yet still contain harmful microbes. Clear water does not always mean safe water.
Germs hiding in germs
Free-living amoebae create another serious problem. These organisms can shelter other harmful microbes inside their cells.
Bacteria and viruses use amoebae as protection from disinfectants and environmental stress. Scientists call this the Trojan horse effect.
Pathogens hidden inside amoebae can travel through water systems undetected. Normal cleaning methods fail to reach these protected microbes. Once released, bacteria and viruses may infect humans more easily.
Researchers also link this process to antibiotic resistance. Microbes that survive inside amoebae adapt and become harder to kill.
This raises long-term risks for public health and medical treatment.
Warming raises the risk
Climate change increases water temperature across the globe. Warm water supports the growth of heat-loving amoebae.
Regions that never faced this problem before may now see new infections.
Recent outbreaks connected to recreational water use have already raised concern in several countries.
Lakes, pools, and water parks create ideal conditions for exposure, especially during heat waves.
As global temperatures rise, experts expect wider spread and higher exposure rates unless stronger prevention methods begin soon.
Protecting water together
The researchers call for a One Health strategy. This approach connects human health, environmental science, and water management into one coordinated effort.
Better monitoring systems can help track amoebae before infections occur.
Improved diagnostic tools can support faster detection in patients and water supplies.
Advanced water treatment methods may also reduce risk. Strong cooperation between scientists, health officials, and water authorities remains essential.
Protection against deadly amoebas
“Amoebae are not just a medical issue or an environmental issue,” Shu said.
“They sit at the intersection of both, and addressing them requires integrated solutions that protect public health at its source.”
Protecting water means protecting people. Early action can prevent a hidden threat from becoming a global crisis.
The study is published in the journal Biocontaminant.
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