A recent study has raised concerns that rodent-borne viruses such as hantavirus could become more prevalent in regions that have never encountered them before, driven by the effects of climate change. This warning comes in the wake of a hantavirus outbreak on the cruise ship MV Hondius, which departed from Argentina carrying approximately 150 passengers. The outbreak has resulted in three fatalities, with over ten confirmed cases. Authorities in multiple countries, including the United Kingdom, are working to contain the virus, which can incubate silently for one to eight weeks.
Rising Risk of Arenavirus Outbreaks
Even if the current outbreak is successfully contained, the study published in the journal npj Viruses indicates that similar outbreaks of arenaviruses—a family of viruses primarily transmitted from rodents to humans—could become more frequent in the coming decades. As rodent populations shift due to climate change, the risk of human infection increases. Pranav Kulkarni, an author of the study, stated, "As climate change accelerates, our study shows how the outbreak risk of dangerous new world arenaviruses could ride on shifting rodent populations to reach millions more people across South America."
Understanding Hantavirus Transmission
Hantaviruses can cause severe hemorrhagic fevers, with hospitalisation rates and fatality rates ranging from 5 to 30 per cent. The disease spreads mainly through contact with rodents, their urine, saliva, or droppings, particularly when these materials become airborne. While hantaviruses have been present for centuries and have caused outbreaks across Asia and Europe, they rarely transmit between humans. However, the new "Andean strain" has shown evidence of human-to-human transmission. Experts suspect that a couple who went bird-watching in Argentina may have brought the virus onto the ship after exposure to infected rodents.
Climate Change and Rodent Habitats
The study tracked how climate change is altering the risk of arenaviruses jumping from animals to humans. Researchers assessed how climate projections affect the habitat suitability for six rat and mouse species linked to these viruses. They identified complex relationships among climate, land use, rodent ecology, and human exposure that traditional models might miss. Pranav Pandit, another author, explained, "Our study connects the dots between changing climatic conditions and land use, shifting rodent populations and human infection risk, making it possible to see where the next generation of zoonotic arenaviral outbreaks could emerge."
Key Drivers of Virus Spread
According to the researchers, the risk of an arenavirus jumping to humans is primarily driven by changes in temperature, rainfall, and land use, such as expanding agricultural and urban areas. These findings highlight an urgent need for coordinated climate-adaptive public health policies. The study predicts that arenaviruses could expand into currently non-endemic areas as reservoir distributions shift under climate change, potentially increasing the risk of human spillover.
Scientists hope that future research will help identify where disease risk is likely to increase, allowing for more detailed analysis and long-term planning to reduce the spread of disease. Dr. Kulkarni concluded, "Then we can look at why it is happening in more detail, identify ways to reduce the risk, and start planning for the long term and ways to reduce the spread of disease."
