IIT Madras & US Researchers Reveal Seasonal Patterns of Freshwater Viruses Linked to Antibiotic Resistance Solutions

New Delhi: Viruses found in freshwater lakes may help keep ecosystems balanced and could offer new solutions for fighting antibiotic-resistant bacteria.

As the COVID-19 pandemic has shown the urgent need to track viruses, a new study by researchers from IIT Madras and the United States reveals that freshwater viruses follow seasonal and yearly cycles. These insights have been published in the journal Nature Microbiology.

The study was led by Dr Karthik Anantharaman, Visiting Professor at the Wadhwani School of Data Science and AI at IIT Madras and Associate Professor of Microbial and Viral Ecology at the University of Wisconsin-Madison. The research team also included scientists from the University of Texas at Austin.

They used advanced machine learning tools to study viruses in 465 freshwater lake samples from Madison, Wisconsin, collected over a span of more than 20 years. This is the longest DNA-based monitoring of a natural environment ever conducted.

Using a method called metagenomics to sequence all the DNA in the lake water, the researchers reconstructed 1.3 million viral genomes, making it the largest study of its kind.

The study found that viruses reappear in seasonal and annual patterns, showing remarkable predictability. They also discovered 578 viral genes that viruses had acquired from their hosts. These genes help carry out key processes like photosynthesis and methane use.

Dr Anantharaman explained the importance of this work,"The COVID-19 pandemic has shown us just how important it is to track viruses. Understanding how viruses emerge, evolve, and interact with their environments is critical, not only for responding to pandemics but also for recognizing the vital roles they play in ecosystems. Yet, long-term studies of viral communities, particularly in natural environments, are rare."

He added, "This lack of data creates a significant knowledge gap, hindering our ability to predict how viruses influence both human health and environmental stability. By investing in long-term viral monitoring, we can better prepare for future outbreaks and uncover the complex ways viruses contribute to the health of our planet."

The study also found that viruses evolve over time, with some genes becoming more dominant due to natural selection. Environmental factors like carbon and ammonium levels, often linked to pollution, were shown to affect viral populations in similar ways as they do other organisms.

Prof Karthik Raman from the Wadhwani School of Data Science and AI at IIT Madras welcomed the findings,"Viruses are everywhere in the environment and play essential, yet often underestimated and misunderstood roles in shaping microbiomes and human health. Contrary to common misconceptions, not all viruses are harmful. Many are integral to maintaining ecosystem health and microbiome stability, much like apex predators such as sharks or lions regulate the balance of ecosystems in the oceans or land."

The researchers say that understanding how viruses function in freshwater systems can help improve how we manage water resources, natural ecosystems, and public health.

This knowledge could lead to new ways of restoring balance in polluted lakes by using viruses to prevent harmful algal blooms or bacterial outbreaks.