One of cholera’s great enemies is found in the human gut

Wellcome Trust Sanger Institute

Facebook

XLinkedInWeChatBlueskyMessageWhatsAppEmail

Cholera-causing bacteria are locked in an evolutionary arms race with a viral nemesis, according to a new genomic study.

Experts at the Wellcome Sanger Institute, icddr,b (International Centre for Diarrhoeal Disease Research, Bangladesh), the Post Graduate Institute of Medical Education & Research (PGIMER), and their collaborators, found that in the Ganges Delta, cholera bacteria rapidly gain and lose special armour that protects against attacks from the virus, known as bacteriophage ICP1.

The new research, published today (1 April) in Nature, highlighted that maintaining these anti-viral defences leads to lower disease severity of cholera in humans and reduced ability to spread outside the country for this bacterial strain.

By looking at the ecology of cholera in South Asia, this study challenges the long-held belief that the Ganges Delta is the global source of cholera. Knowing more about the strains and the factors that influence the spread of cholera bacteria in different regions could help provide an early warning system, identifying high-risk strains before they escalate and allowing for early intervention.

It could also help develop new treatments, for example, research into whether the virus could be harnessed to help stop cholera in the future.

Cholera is an acute diarrheal infection, which can be fatal within hours if untreated. It is caused by the bacterium, Vibrio cholerae (V. cholerae), which spreads through contaminated food and water1. Globally, we are in the seventh cholera pandemic, which started in 1961, with an estimated 1.3 to 4 million cases and up to 143,000 deaths per year from the condition worldwide1. It has been shown that the seventh pandemic is caused by V. cholerae strain 7PET O1, originating from the Bay of Bengal, which borders Bangladesh and India, and it was thought that the Ganges Delta was the global source of cholera.   

This new research sequenced bacterial samples from across Bangladesh and North India, creating the most comprehensive dataset of cholera in this area to date, containing over 2,300 genomes collected across approximately 20 years. They found that it was the Ganges Basin, not the Ganges Delta, that was the primary global source of cholera in that time.

By tracking the bacterial spread, they also uncovered that the bacteria do not simply follow the flow of rivers. Instead, they tend to stay within national borders, suggesting that human travel and population density are more important for cholera transmission than the natural environment.

They also found V. cholerae in Bangladesh, strain 7PET O1, rapidly gain and lose genetic elements known as defence systems, which act like armour helping them survive against their viral nemesis, the bacteriophage ICP1. Bacteriophages, also known as phages, are natural viruses that attack bacteria. They need bacteria to replicate, are generally not harmful to human cells, can rapidly kill their bacterial host, and are often found in the human gut microbiome.

By analysing cholera data in South Asia spanning 20 years, the team found evidence that the bacteria are constantly fighting off attacks from ICP1 using different armour or shields. In turn, the study shows that the ICP1 virus develops its own ‘anti-defence’ weapons to hack through those shields and continue its attack. While it has been shown previously that the presence of ICP1 in the gut is linked with less severe disease2, as the virus kills off the disease-causing bacteria2, this study shows that there is an evolutionary arms race in Bangladesh between the bacteria and ICP1, with each species developing new ways to defeat the other. This compromises the bacteria's ability to spread out of the country, limiting its ability to spread globally.

In the future, it may be possible to use our understanding of this arms race to develop new treatments or control strategies for cholera.

The study suggests that a better understanding of the natural ecology of this important disease could lead to early warning systems, highlighting V. cholerae bacteria that have lost new types of defensive shields and are more likely to cause severe disease and spread globally to cause epidemics. By identifying these high-risk strains before they spread, authorities could update treatment recommendations, deploy vaccines and improve water sanitation in specific areas to prevent local outbreaks from turning into global pandemics. Overall, by taking an ecological view of the global source of cholera, it is possible to stop the spread of these disease-causing bacteria to other parts of the world.

Dr Amber Barton, co-first author at the Wellcome Sanger Institute, said: “Our research uncovered the evolutionary struggle between cholera bacteria in Bangladesh, and the bacteriophage that preys on them. Specifically, the discovery of rapid loss and gain of V. cholerae’s protective defences and their impact on disease severity is key to understanding the factors involved in the spread of this bacterium. Without the defences, the bacteria are more dangerous to humans, and tracking this in real time, through genomics, can help us identify when the strains pose the highest risk and intervene early. Additionally, future research into cholera and microbiome interactions in other regions of the world could reveal other phages that prey on the bacteria, which may help develop new treatments in the future.”

Dr Firdausi Qadri, co-senior author at the icddr,b in Bangladesh, said: “By creating the most comprehensive genetic database of cholera bacteria samples across Bangladesh and North India, our study has shown that our understanding of the global source of cholera needs updating and refinement to consider a region that spans Bangladesh and India. We can also see that cholera spread does not follow the rivers and waterways. This suggests that, despite cholera being a water-borne pathogen, the role of human travel and population density are bigger factors in cholera transmission than the surrounding environment. Understanding this can help inform public health interventions to help stop the spread of infections.”

Professor Nick Thomson, co-senior author at the Wellcome Sanger Institute, said: “The world is in its seventh global pandemic of cholera, with the bacteria evolving and adapting to treatments and the world around it. By taking an ecological view of cholera across whole regions of the world using genomics, we have been able to dispel previous inaccuracies about the global spread of the pandemic and provide a clearer picture of the factors and threats these bacteria face. This can help inform public health strategies and future treatments to hopefully end this pandemic and protect the many thousands of people impacted.”

ENDS

Notes to Editors:

1. Cholera. World Health Organization. Available at https://www.who.int/news-room/fact-sheets/detail/cholera [accessed March 2026]
2. N. Madi, et al. (2024) 'Phage predation, disease severity, and pathogen genetic diversity in cholera patients.' Science. DOI:10.1126/science.adj3166

Publication:

A. Barton, M. H. Afrad, A. Taylor-Brown, et al. (2026) ‘Evolution of Pandemic Cholera at its Global Source’. Nature. DOI: 10.1038/s41586-026-10340-x

Funding:

This research was part-funded by the Bill and Melinda Gates Foundation and Wellcome.

Selected websites:

The Wellcome Sanger Institute

The Wellcome Sanger Institute is a world leader in genomics research. We apply and explore genomic technologies at scale to advance understanding of biology and improve health. Making discoveries not easily made elsewhere, our research delivers insights across health, disease, evolution and pathogen biology. We are open and collaborative; our data, results, tools, technologies and training are freely shared across the globe to advance science.

Funded by Wellcome, we have the freedom to think long-term and push the boundaries of genomics. We take on the challenges of applying our research to the real world, where we aim to bring benefit to people and society.

Find out more at www.sanger.ac.uk or follow us on Twitter, Instagram, Facebook, LinkedIn and on our Blog.

About Wellcome

Wellcome supports science to solve the urgent health challenges facing everyone. We support discovery research into life, health and wellbeing, and we’re taking on three worldwide health challenges: mental health, infectious disease and climate and health. https://wellcome.org/

---

Journal

Nature

DOI

10.1038/s41586-026-10340-x 

Article Title

Evolution of Pandemic Cholera at its Global Source

Article Publication Date

1-Apr-2026

 

Lakes forming next to Greenland’s melting ice sheet are speeding up glacier flow 

University of Leeds

Facebook

XBlueskyMessageWhatsAppEmail

Images available here  

A growing network of meltwater lakes at the edge of the Greenland ice sheet is accelerating the flow of major glaciers, potentially increasing the pace of global sea‑level rise. 

Warmer air and sea temperatures have led to the loss of around 264 gigatons of ice every year in Greenland since 2002 causing sea levels to rise by 0.8 millimeters annually. But a new study by the University of Leeds examining glacier behaviour across the entire ice sheet has highlighted a lesser‑known feature that is amplifying this mass loss - the freshwater lakes forming as the ice retreats. 

These ice-marginal lakes (or IMLs) sit right up against the edge of the ice and appear as glaciers pull back and expose deep, bowl‑shaped hollows in the landscape. Meltwater quickly pools in these basins to form lakes as large as 117 km2 in area.   

The study which is published today (1 April) in the journal Communications Earth and Environment shows that far from being passive features of the landscape, the lakes can destabilise the glaciers that feed into them, triggering movement, increasing thinning, and heightening ice loss. 

The researchers examined satellite data, using maps of ice-marginal lakes across Greenland and the flow at the ice sheet surface. They found that the speed of glaciers ending in lakes was over three times faster at their fronts than those glaciers ending on land. Crucially, that acceleration wasn’t confined to the glacier edge, with the effect being detected up to 3.5 km inland. 

Lead author of the study Connie Harpur, a post-graduate researcher in Leeds’ School of Geography, said: “Our findings are significant because glacier speed plays a major role in how quickly ice is lost from the Greenland Ice Sheet. When glaciers flow faster, they deliver more ice to lower elevations, where it can melt, or to their fronts, where it can break away.  

“By showing that lakes at the ice margin can substantially speed up glaciers, we identify an important process that needs to be included in predictions of future ice loss.” 

Around 10% of Greenland’s ice edge is currently bordered by freshwater lakes with that figure expected to rise sharply as the climate warms and more depressions are exposed during ice retreat.  

Much like glaciers that flow into the ocean, those ending in lakes can experience a form of flotation, where the water partly lifts the glacier front, increasing melting under the ice. This makes it easier for large slabs of ice to break off in a process known as calving and reduces the friction that usually slows the glacier’s flow. 

Earlier observations from mountain ranges such as the Himalayas have shown that glaciers terminating in lakes can move twice as fast as nearby glaciers ending on land. But until now, scientists had only limited evidence of how widespread these effects might be in Greenland. 

The Leeds researchers warn that this omission could be significant. Ice dynamics (the ways in which glaciers speed up, slow down, and deform) are expected to be the main driver of Greenland’s ice loss in the coming decades and with lake formation accelerating alongside climate warming, the study’s authors argue that models urgently need to account for the role of IMLs. 

Co-author of the study Professor Mark Smith added: “If we do not account for lake effects, we may underestimate how dynamically parts of the ice sheet respond to future warming, and in turn how much Greenland will contribute to future sea level rise. 

“Understanding ice-marginal lakes’ influence on glacier flow is crucial for accurate projections.” 

Ends 

Further information 

Images available here 

Image captions: 

An ice-marginal lake in southwest Greenland. Photo- Connie Harpur. 

Two outlet glaciers draining into ice-marginal lakes, seen in Copernicus Sentinel-2 satellite imagery (August 2025, processed by Connie Harpur).  

Ice-marginal proglacial lakes enhance outlet glacier velocities across Greenland is published in Communications Earth and Environment. The DOI is 10.1038/s43247-026-03363-9 

The research is funded by a NERC Doctoral Training Partnership 

For media enquiries, please contact Kersti Mitchell via k.mitchell@leeds.ac.uk 

University of Leeds  

The University of Leeds is one of the largest higher education institutions in the UK, with more than 40,000 students from about 140 different countries. We are renowned globally for the quality of our teaching and research.  

We are a values-driven university, and we harness our expertise in research and education to help shape a better future for humanity, working through collaboration to tackle inequalities, achieve societal impact and drive change.  The University is a member of the Russell Group of research-intensive universities, and is a major partner in the Alan Turing, Rosalind Franklin and Royce Institutes www.leeds.ac.uk   

Follow University of Leeds or tag us in to coverage: Bluesky | Facebook | LinkedIn | Instagram 

 

---

Journal

Communications Earth & Environment

DOI

10.1038/s43247-026-03363-9 

Method of Research

Data/statistical analysis

Subject of Research

Not applicable

Article Title

Ice-marginal proglacial lakes enhance outlet glacier velocities across Greenland

Article Publication Date

1-Apr-2026

 

Aquaculture is shifting toward less sustainable species: new UBC study

While aquaculture has grown rapidly to meet global seafood demand, it is increasingly relying on species that are less beneficial for food security, climate mitigation, and biodiversity, said a new study from researchers at UBC

University of British Columbia

Facebook

X
Bluesky
Email

 

image: 

Integrated seaweed and abalone farm in Xiamen, China

view more 

Credit: William Cheung/IOF

Aquaculture is shifting toward less sustainable species: new UBC study

While aquaculture has grown rapidly to meet global seafood demand, it is increasingly relying on species that are less beneficial for food security, climate mitigation, and biodiversity, said a new study from researchers at the University of British Columbia.

The study, published in Fish and Fisheries, analyzed global aquaculture production from 1950 to 2023 and found that, since the 1980s, the industry has shifted toward a smaller number of intensively farmed species—particularly finfish—that tend to have lower overall sustainability potential.

“Aquaculture has enormous potential to support global food systems and environmental goals, but our findings show that current production trends are moving us in the wrong direction,” said Dr. William Cheung, professor and Director of the Institute for the Oceans and Fisheries (IOF), and senior author of the study. “We’re seeing a growing mismatch between what we produce and what would best support climate, biodiversity, and food security outcomes.”

The research used a traits-based approach to evaluate how different species contribute to three key areas: food provision, climate impact, and biodiversity. It found that earlier aquaculture systems—dominated by species such as seaweed and shellfish—had higher sustainability potential compared to modern systems focused on fed species like salmon and shrimp.

The study developed indices that measured how aquaculture production contributes to food, climate, and biodiversity goals, along the UN Sustainable Goals agenda. They noted that China, for example, accounted for 56 per cent of global aquaculture production in 2022, yet its production mix showed declines across all three indices between the 1976–1980 baseline and 2019–2023: −14.1 per cent for food, −21.6 per cent for climate, and −12.9 per cent for biodiversity. In the Americas, the food index increased only marginally (+0.8 per cent), while the climate and biodiversity indices declined by 11.4 per cent and 9.1 per cent, respectively.

“Salmon aquaculture is currently the fastest-growing food sector in the world however, it is strongly affected by warming waters and deoxygenation, and is a species that has lower FCB potential,” said Aleah Wong, lead author and PhD candidate in the IOF. “Not all aquaculture species are equal. Some, like bivalves and seaweed, can deliver significant environmental benefits, while others come with higher trade-offs,” she said. “Currently, many of the most beneficial species are under-represented in global production.”

“Food security is shaped by factors like production efficiency and species’ nutrient density, but also by complex dynamics between producers, consumers, markets and regulatory bodies that affect food security indirectly through impacts on food availability, access, trade, income and equity,” said Dr. Cheung. “Many regions already farm species with high sustainability potential. By scaling up these species and diversifying production, aquaculture can better contribute to global sustainability targets.”

The researchers point to expanding the production of low-impact species—such as bivalves and seaweed—as a key pathway forward. However, they note that market demand, policy frameworks, and consumer preferences will play a critical role in enabling this transition.

“Shifting toward more sustainable aquaculture would require coordinated international action,” said Wong. “Better policies, investment in innovation, and changes in what consumers are willing to eat need to be made.”

The study underscored that the future of aquaculture depends not only on how much is produced, but on what is produced—and how those choices align with global environmental and food system goals.

“Shifting Trends in Aquaculture's Biological Potential to Address Food, Climate and Biodiversity Challenges” was published in Fish and Fisheries.

 

---

Journal

Fish and Fisheries

DOI

10.1111/faf.70081 

Method of Research

Meta-analysis

Subject of Research

Animals

Article Title

Shifting Trends in Aquaculture's Biological Potential to Address Food, Climate and Biodiversity Challenges

Article Publication Date

25-Mar-2026

COI Statement

The authors declare no conflicts of interest.

 

Delhi: CPI(M)Seminar Voices Need for Organised Resistance Against Imperialist Aggression

Mukund Jha | 30 Mar 2026

• 
  
• 
  
• 
  

The presence of a substantial youth audience reflected the growing concern among them about global conflicts, imperialist interventions, and their consequences.

Image Courtesy: CPIM Facebook

New Delhi: As tensions continue to escalate in West Asia after US-Israel attacked Iran, a seminar held in New Delhi expressed deep concern over the rapidly evolving global situation, the expanding role of imperialist powers, and the deepening humanitarian and economic crises that accompany such interventions. Speakers at the seminar voiced their shared concern about intensifying militarisation, the erosion of international norms, and the cascading impact of wars on everyday life.

Titled “Imperialist Aggression & Its Impact”, the seminar, organised under the banner of the Coalition Against Imperialism, was held at Harkishan Singh Surjeet Bhawan on Sunday, drawing a packed audience. The event brought together a wide spectrum of participants — activists from Left mass organisations, academics, journalists, diplomats, and notably, a large number of youths.

The presence of a substantial youth audience stood out. Their engagement, attentiveness, and participation reflected the growing concern among India’s young generation about global conflicts, imperialist interventions, and their consequences. If anything, the composition of the gathering underscored a broader political message: that opposition to imperialism is not confined to older ideological traditions but is finding resonance among contemporary youth.

A World in Turmoil

Opening the discussion, Communist Party of India (Marxist) politburo member R. Arun Kumar set a sombre tone, placing the seminar within what he described as a “deeply unstable global moment.”

“The genocidal attack on Palestine carried out by Israel with the active support of the US… though there is only a namesake ceasefire, attacks are still continuing in Gaza and the occupation in the West Bank has increased,” he said.

Reflecting on the broader international climate, Kumar added: “We are living in what is called ‘interesting times’, but these are not hopeful times—these are very difficult times marked by wars, aggression and instability across regions.”

He pointed to the continuity in US foreign policy, arguing that interventions in countries such as Iraq, Iran, and Venezuela reveal a pattern rather than isolated events. Recalling the 2003 invasion of Iraq, he noted that wars justified on dubious grounds have had long-lasting consequences, destabilising entire regions.

Media, War and Public Opinion

Among the prominent speakers was N. Ram, senior journalist and former Editor-in-Chief of The Hindu, who placed a sharp critique of US foreign policy and the narratives that accompany it.

“This seminar is designed to focus on the current military attacks violating the sovereignty of numerous countries. As far as we know, President Trump has bombed at least seven countries during his time in office. He came to the White House promising to end endless wars, but we know what actually happened.”

Highlighting contradictions within dominant global narratives, Ram observed: “Today, even conservative publications like The Economist are pointing out the contradictions—claims of destroying 100% of Iran’s capabilities, while the remaining 0% is enough to disrupt the global economy by choking oil supply.”

He characterised the ongoing escalation as a “war of choice” and drew attention to dissent within the US itself: “We are also seeing mass protests across the the US under the ‘No Kings’ movement… It is very important to pay close attention to the mood of the American people.”

In a strongly worded intervention, Ram described the attacks on Iran “a totally unprovoked, brutal and fascistic attack,” adding that such actions violated international law and the UN Charter. He also pointed to the global economic ripple effects, particularly through disruptions in oil supply routes such as the Strait of Hormuz — consequences that directly affect countries like India.

Turning to India’s foreign policy, Ram was critical: “In total contrast, the BJP government’s response has been shameful… its actions created an impression of complicity at a very critical moment.”

He further argued that India’s strategic alignment with the US and Israel marked a significant departure from its historical commitment to non-alignment and anti-colonial solidarity.

‘Age of Stupid Evil’: Reframing Imperialism

Journalist Seema Chishti began her remarks with a short video illustrating Iran’s military response — a deliberate attempt to challenge dominant perceptions.

“We are living in what I would call the ‘age of stupid evil’—a time where the most absurd things coexist with the most horrifying realities,” she added.

Rejecting contemporary euphemisms, she argued “We can stop using the word ‘neo’. What we are witnessing is not neo-imperialism—it is colonialism 101.”

For Chishti, the driving force behind current conflicts is unmistakable “This is fundamentally about resources—oil, lithium, precious metals.”

She also emphasised the dehumanisation inherent in such conflicts, noting how populations in Palestine, Lebanon, and Iran are reduced to abstractions within geopolitical calculations.

A striking dimension of her analysis focused on technology “What we are witnessing very clearly is the role of Big Tech—not just as information platforms, but as active enablers of war.”

She highlighted the convergence of economic power, data control, and military interests, arguing that this nexus had made the political economy of war more visible than ever.

Voices from Global South

Adding an international perspective, diplomat Juan Carlos Marsan Aguilera, representing Cuba, spoke about the wider implications of US and Israeli actions.

“Every day we wake up to the news of the US and Israeli war against Iran… which generates tragedies and human suffering and impose instability on oil markets,” he said and warned of a pattern: “Yesterday it was Palestine, then Venezuela, now Iran. Tomorrow it may be Cuba.”

Aguilera strongly condemned economic blockades, describing their impact on everyday life in Cuba — from healthcare to food production — and called for global solidarity.

Building Unity Against Imperialism

CPI(M) politburo member Nilotpal Basu said the “central question before us today is—are we prepared?”

He emphasised the direct connection between global events and domestic realities, “Rising prices—especially of essential goods like cooking oil and fuel—have made global imperialist actions a domestic issue.”

Basu argued that building broad anti-imperialist unity requires translating these connections into political understanding among the masses.

“Unless we explain how these global developments affect daily lives, we cannot build a meaningful movement.”

He proposed the idea of a wider platform — “World Against Imperialism” — to bring together diverse sections in a coordinated campaign.

A Question of Sovereignty and Resistance

Political leader Rajaram Singh reiterated the continuity of imperialism as a system: “Imperialism has not disappeared—its form may have changed, but its character remains the same.”

He stressed that the struggle is not about religion or region, but about control over resources and markets “A handful of powerful nations and corporations want to dominate the world’s natural resources. This monopoly is unacceptable.”

Calling for unity, he added“Workers, farmers, and all sections of the working people must unite to defend their rights.”

A Clear Message

The seminar concluded with a shared understanding of urgency for some kind of broad organised resistance against imperialism and war and its tangible consequences — rising prices, economic instability, erosion of democratic norms, and human cost.

The call for solidarity — across nations, movements, and social groups — was presented as a political necessity in an increasingly polarised world.

(Note: This report, written in Hindi, has been translated with AI assistance.)