A new study reveals that the proportion of Greenlanders carrying antibodies to Leptospira—a bacterium spread through contaminated water—rocketed from 2.5 % in 1998 to 30 % in 2013. This six‑fold surge highlights how warming temperatures and compromised water supplies may be fuelling zoonotic disease risks in the Arctic, raising urgent questions about the safety of drinking water and the health of northern communities.
A six‑fold surge in Leptospira infections
The Arctic is warming faster than any other region, and melting ice, thawing permafrost and expanding habitats for disease‑carrying animals are opening new pathways for microbes to jump from animals to people.
The samples were frequency‑matched for sex, age, ethnicity and place of residence and were tested for antibodies against several climate‑sensitive pathogens, including Leptospira spp., Rickettsia spp., Brucella melitensis/abortus, Francisella tularensis, Coxiella burnetii, tick‑borne encephalitis virus and Borrelia burgdorferi.
What the study found
The results are striking. In Greenland, the proportion of people with antibodies to Leptospira jumped from 2.5 % in 1998 to 30 % in 2013—a roughly six‑fold increase (odds ratio 16.7; 95 % CI 5.7–48.9). By 2013, seroprevalence in Greenland (18 %, 95 % CI 13–24 %) far exceeded levels in Sweden during 2012–2017 (4 %, 95 % CI 2–8 %). This is the first report of human Leptospira infection in Greenland, and the authors attribute the rise to contaminated water sources and global warming.
Other pathogens painted a mixed picture. Antibodies to Rickettsia spp. remained around 12 % throughout the study period, indicating widespread but stable exposure. Francisella tularensis and Brucella melitensis/abortus were extremely rare in Greenland (<1 % in 2013). In Swedish samples, antibodies to Brucella spp. (1 %), Borrelia burgdorferi (2 %), Francisella tularensis (3 %) and tick‑borne encephalitis virus (5 %) were detected, while no antibodies to Coxiella burnetii were found. The researchers also tested polar bears and found that two of 81 animals carried Leptospira antibodies, hinting that the bacterium circulates in Arctic ecosystems.
These findings suggest that the combination of contaminated water—potentially from increased flooding or animal urine—and warming temperatures is driving a dramatic rise in Leptospira infections. The authors call for updated public‑health data and stress the importance of an integrated One Health approach that links human, animal and environmental health.
Why Arctic communities should worry
ArcSolution researcher Christian Sonne explains in this interview, that the Arctic functions as a “global thermometer”—a place where climate change, pollution, biodiversity loss and disease intersect. Pollutants produced at lower latitudes travel north, accumulate through biomagnification, and reach high concentrations in top predators and the people who rely on them for food. Sonne warns that “everything is connected”; pollutants and warming temperatures make animals and people more susceptible to infection.
Warming also drives ecological change: new species and disease vectors move north, while thawing permafrost releases long‑dormant microbes and creates conditions that favour pathogen survival. The combination of pollutants, climate change and biodiversity loss creates a “perfect storm for zoonotic spillover”, raising the risk of diseases jumping between animals and humans. Sonne cautions that the Arctic could become the epicentre of a future pandemic and stresses the importance of Indigenous knowledge and collaboration.
The Greenland Center for Health Research (GCHR) notes that climate change may fundamentally alter disease patterns in the North and echoes the study’s finding that Leptospira seroprevalence increased dramatically from about 2–3 % in 1998 to 30 % in 2013. The GCHR emphasises that updated public‑health data and planning are urgently needed.
Concrete steps to protect Arctic health
The six‑fold surge in Leptospira infections is more than a scientific curiosity—it is a warning signal that demands action. Experts outline several concrete steps:
Fix the water infrastructure. Rising Leptospira infections suggest that drinking water may be contaminated by animal urine or flooding. Improving wastewater management, upgrading pipes and ensuring that remote communities have reliable access to clean water should be a top priority.
Train and equip health workers.
Febrile illnesses in the Arctic are often treated empirically without testing for zoonoses. Training health‑care providers to recognise symptoms of Leptospira and Rickettsia, providing rapid diagnostics and ensuring access to appropriate antibiotics can reduce morbidity.
Build a One Health surveillance network. The authors and ArcSolution researchers call for transdisciplinary collaboration involving scientists, Indigenous communities and policymakers. Monitoring wildlife, domestic animals, environment and human health together can detect emerging threats early and help prevent spillovers.
Act on climate and adaptation.
Cutting greenhouse gas emissions and reducing pollutants will indirectly protect Arctic health. At the same time, local adaptation—building homes and infrastructure resilient to thawing permafrost and extreme weather—can reduce vulnerability.
A wake‑up call
The One Health study shows that Leptospira infections in Greenland have risen six‑fold and that Rickettsia exposure remains widespread.
These trends likely reflect the combined effects of climate change, contaminated water and ecological shifts. For Arctic communities, this is not an abstract threat: it points to compromised water supplies, increased flooding and a future in which pathogens once considered tropical may flourish in the North. Ignoring these warnings risks more outbreaks and erodes trust in public health.
Concrete action is possible. Upgrading water and sanitation systems, training health workers, building cross‑disciplinary surveillance networks and accelerating climate mitigation can reduce the risk of zoonotic diseases in the Arctic.
As temperatures continue to rise, acting on the lessons of this study will be crucial for safeguarding the health of Northern peoples and ecosystems.
Conclusion
The One Health study of seven climate‑sensitive zoonoses reveals a worrying rise in human Leptospira infections in Greenland and widespread exposure to Rickettsia.
These trends likely reflect the combined effects of climate change, contaminated water and ecosystem shifts. In the Arctic, where people, animals and the environment are tightly intertwined, such changes have profound implications.
Strengthening surveillance, investing in clean water infrastructure, and adopting an integrated One Health approach will be crucial for safeguarding health as the region continues to warm.