image: Graphical Abstract
Credit: Dr. Mats Leifels, et al
A new study published in Water & Ecology reveals that common waterborne amoebae can ingest and protect human viruses, extending their environmental persistence. Human norovirus (HNoV) and human adenovirus (HAdV)—major causes of acute viral gastroenteritis worldwide—are transmitted through contaminated water and food. The study shows these viruses can enter and persist within FLA, including Vermamoeba vermiformis, Acanthamoeba polyphaga, and Willaertia magna.
“HNoV and HAdV can be internalized and persist inside FLA, which are highly abundant in all natural and man-made aquatic environments,” explains co-corresponding author Dr. Mats Leifels. “This potentially provides both enteric viruses with a protective vessel to bypass widely used water disinfection treatments such as UV, chlorine and monochloramine—methods that have already been suspected to be insufficient for removing high virus loads.”
Using quantitative PCR and fluorescence microscopy, the researchers observed HNoV accumulating in the cytoplasm and vacuoles of V. vermiformis and A. polyphaga, while HAd localized within the nucleus of W. magna. “Intact virions of both viruses persisted inside amoebae—including trophozoites, cysts, and extracellular vesicles—for up to 12 days,” shares Leifels. “HAdV retained infectivity after internalization, indicating that these viruses can evade amoebal digestion and structural degradation.”
In the case of HAdV, nuclear incorporation, preservation of capsid integrity and detection of mRNA associated with adenoviral fiber protein further suggest possible viral transcriptional activity within the amoebae hosts.
These findings challenge current assumptions about virus removal in water treatment processes food safety protocols and drinking water production. “FLA serve as reservoirs and transport vessels for enteric viruses. The enhanced persistence and protection conferred by ubiquitous FLA suggest a potential impact on microbial risk assessments for sewage-impacted rivers, lakes, and water reuse systems,” adds Leifels.
The study highlights the need to re-evaluate water and sanitation guidelines to better mitigate environmental transmission pathways.
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Contact the author:
Dr. Mats Leifels, mats.leifels@rub.de
-Division Water Quality and Health, Department of Pharmacology, Physiology, and Microbiology, Karl Landsteiner University of Health Sciences, Dr.-Karl-Dorrek-Straße 30, A-3500 Krems an der Donau, Austria
-School of Public Health, University of Alberta, Edmonton, AB T6G 2G7, Canada
-Singapore Centre for Life Science Engineering, Nanyang Technological University, Singapore 637551, Singapore
Dr. Rafik Dey, rafikdey@gmail.com
-School of Public Health, University of Alberta, Edmonton, AB T6G 2G7, Canada
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Journal
Water & Ecology
Method of Research
Observational study
Subject of Research
Cells
COI Statement
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.