A new study warns that rodent-borne viruses like hantavirus are likely to spread to more countries that have never faced these diseases due to climate change, putting new communities at risk.
Current Outbreak on Cruise Ship
The cruise ship MV Hondius, which set off from Argentina carrying about 150 people, has been at the centre of a hantavirus outbreak that has so far claimed the lives of three passengers. With over 10 confirmed cases since the outbreak began, officials in several countries, including the UK, are scrambling to contain the spread of the virus, which can silently incubate in patients for between one and eight weeks.
Study Predicts Increased Risk
Even if the current outbreak is contained, a new study published in the journal npj Viruses warns that outbreaks of arenaviruses could become more common in the coming decades as shifting rodent populations raise the risks of human infection. Arenaviruses are a family of viruses mainly transmitted to humans from infected rodents.
“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,” said Pranav Kulkarni, an author of the study.
Such viruses can cause severe hemorrhagic fevers with high hospitalisation rates and fatality rates ranging from about 5 to 30 per cent.
Transmission and Risks
The disease is mainly spread by contact with rodents, their urine, saliva or droppings, and particularly when the material is disturbed and becomes airborne. Although they have been present for centuries, with a documented history of outbreaks across Asia and Europe, hantaviruses rarely pass between humans. However, the new “Andean strain” is the only one showing 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 being exposed to infected rodents.
Climate Change and Rodent Populations
In the new study, scientists tracked how climate change is reshaping the risk of arenaviruses jumping from animals to humans. They assessed how climate projections changed the habitat suitability for six rat and mouse species linked to the viruses. Scientists could identify complex relationships among climate, land use, rodent ecology and human exposure that traditional models may miss.
“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,” said Pranav Pandit, another author of the study.
The risk of an arenavirus jumping to humans from rats is mainly driven by changes in temperature, rainfall, and land use change, such as expanding agricultural and urban areas, researchers found.
Urgent Need for Policy
These findings underscore an urgent need for coordinated climate-adaptive public health policies, they say. “Our models predicted that arenaviruses could expand into currently non-endemic areas as reservoir distributions shift under climate change, potentially increasing the risk of human spillover,” researchers wrote in the study.
Scientists hope future studies can inform where we can expect the disease risk to increase. “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,” Dr Kulkarni said.
