'Bacteriophages are fecal indicators, can harm humans': 'The Liver Doc' fact-checks study on self-purifying Ganga water

A recent study claimed that the Ganga river has 1,100 types of bacteriophages that selectively target and destroy bacteria, thus purifying the water naturally. Researcher Dr Ajay Sonkar, who conducted the study, even described these bacteriophages as “security guards” of the Ganga, capable of identifying and eliminating harmful bacteria introduced by bathers in the ongoing Maha Kumbh Mela.

However, Dr Cyriac Abby Philips, popularly known as The Liver Doc on X, Sunday questioned the claim and called it a piece of misinformation and ignorant claim. "The presence of large numbers of bacteriophages is a measure of severe bacterial contamination from various sources including human excreta. Sewage water contains very large amounts of bacteriophages. It doesn't make it drinkable," he shared in a long post on X. 

His tweets came in response to the report that the Ganga River has a self-purification mechanism due to the presence of 1,100 types of bacteriophages. The study claimed that each bacteriophage rapidly produces 100-300 new ones, ensuring a continuous cycle of purification.

However, The Liver Doc went on to reason that if anything, bacteriophages are an indirect measure of the bacterial contamination of the water source. "Bacteriophages are promising tools for the detection of fecal pollution in different environments, and particularly for viral pathogen risk assessment. Bacteriophages are also viruses - they can also severely harm humans. Their presence in the water does not indicate better outcomes," he tweeted. 

"To simplify this, the presence of bacteriophages in water does not equate to "cleaner" water... Bacteriophages can be used as fecal indicators or microbial water quality bioindicators as an early warning of contamination by sewage, and as an efficiency marker of water or wastewater treatment (See Yahya et al., Journal of Applied Microbiology 2015)," 'The Liver Doc' added. Dr Philips slammed the study and media reports for misinterpreting scientific data. 

What are bacteriophages?

Bacteriophages are viruses that infect and destroy bacteria. While they play an essential role in microbiology, their presence in water is not a sign of cleanliness. Instead, high levels of bacteriophages indicate severe bacterial contamination, often from sewage or human excreta.
The presence of bacteriophages in water does not indicate cleanliness—it signals potential contamination.