Outbreaks like hantavirus could become more common in coming years – here’s why

Rodent-borne viruses like the hantavirus are likely to spread to more countries that have never faced these diseases due to climate change, putting new communities at risk, scientists warn in a new study.

A cruise ship MV Hondius, which ​set off from Argentina, carrying about 150 people has been the centre of a hantavirus outbreak, which has so far taken the lives of three passengers.

With over 10 hantavirus cases confirmed since the outbreak, 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.

Even if the current outbreak is contained, a new study warns that outbreaks of such 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 published in the journal npj Viruses.

Such viruses can cause severe hemorrhagic fevers with high hospitalisation rates and fatality rates ranging from about 5 to 30 per cent.

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.

A couple who went bird-watching in Argentina may have brought the virus onto the ship after being exposed to infected rodents while birdwatching, experts suspect.

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.

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.