How Argentina’s Weather Contributed to the Hantavirus Shipwreck

An outbreak of hantavirus in MV Hondius the ship has made a global health problems. But its driver is rats that weigh about an hour, and this year’s climate change has helped increase the chances of transmission.

Throughout the Southern Cone, researchers have been correlating wet years with the population of rodents known there. recorded-which can increase the spread of hantavirus. This year’s increase reflects the spread of disease caused by climate change, environmental disruption, and an increasingly connected world.

“This is an emerging disease because the distribution of reservoirs and viruses is expanding,” says Karina Hodara, a researcher at the Faculty of Agronomy at the University of Buenos Aires who studies the ecology of hantaviruses. “People travel across continents in a matter of hours.”

The long-tailed pygmy rat is a common name several types those living in Chile and Argentina who may be infected with hantavirus. Each type is associated with different hantaviruses depending on geography.

It is not yet known where the first people who got sick from the Andes virus got the virus. But the Patagonian long-tailed pygmy rice rat (Oligoryzomys longicaudatus), which lives in the south of Argentina and forests and shrubs in Chile and weighs about an hour, is the main reservoir of the only known hantavirus that can spread from rodents to humans and between humans. This human-to-human transmission “is what makes epidemics happen,” he adds Raúl González Until nowan expert in genetics and evolution at the National University of Córdoba.

But some rats, including the Pampas long-tailed pygmy rat (Oligoryzomys flavescens), can transmit the virus to humans. The spread of the virus is controlled by environmental changes. When food is abundant—following events such as the flowering of Patagonian bamboo (Chusquea culeou) or during periods of increased fruit production from herbs such as rosehips and blackberries—rat populations can increase rapidly. “They eat without limits,” says Hodara. “Then they start giving birth very quickly.”

As more rats compete for space, food, and breeding opportunities, aggressive encounters between males increase. This can increase the spread of the virus through bites or saliva. When infected, rodents shed the virus into the environment through urine, feces, and saliva.

Long pygmy rice rats climb and can walk in trees more than 2 meters. This has both positive and negative effects,” he says. Isabel Gómez Villafaneresearcher at the Institute of Ecology, Genetics and Evolution at the University of Buenos Aires. On the other hand, contaminated urine or faeces placed on the surface are more exposed to ultraviolet radiation, which inhibits the virus. On the other hand, in closed spaces – such as sheds, sheds, or houses – the virus can persist for a long time. And when people travel in these areas, especially in the warmer months, contact with contaminated areas becomes easier.

Climate change is one of the biggest drivers of population growth Oligoryzomys colors. In dry years, there is less food for rodents, which can reduce the population, while the opposite is true in wet years, which creates an opportunity for the spread of viruses.

According to González Ittig, this is something that clearly explains the increase in hantavirus cases recorded since last June.

Health officials said 101 confirmed casesmost concentrated in Central Argentina and is related to the Lechiguanas type of HIV that is spread by Oligoryzomys flavescens– double the amount of the previous 12 months.

González Ittig said: “We were coming from a severe drought, and in 2025 the rains started to fall when El Niño arrived. In the middle of Argentina it rained more, according to the climate of the country, after years of drought. Patagonia, however, experienced very inconsistent patterns, with rain in some parts of the Andean but not enough rain in others. Researchers say that this change can increase the growth of plants and increase the availability of food for rodents.