arenavirus spread – New simulations suggest climate shifts could help rodent-borne arenaviruses expand in South America, raising future outbreak risk.
A warming climate could quietly redraw the map of where dangerous rodent-borne viruses can reach people in South America, according to new research.
Researchers report that rising temperatures and changing rainfall patterns may encourage certain rodent species to move into new areas where they could carry arenaviruses—an important group of viruses linked to severe hemorrhagic fevers.. The work. published April 15 in npj Viruses. highlights a risk that may not be on the public health radar in places not currently considered vulnerable.
The concern extends beyond one pathogen at a time.. One rodent-transmitted virus making headlines is Andes virus. a type of hantavirus. which has sickened passengers aboard a cruise ship that started its voyage in Argentina. with some deaths reported.. Hantaviruses are only part of the broader picture. however. because rodents can transmit many different pathogens to people. and arenaviruses are among the most consequential.
Arenaviruses include viruses responsible for Lassa fever in parts of Africa. and in South America they have also caused sporadic outbreaks.. Among the arenaviruses previously implicated in outbreaks are Guanarito virus, Junin virus and Machupo virus.. The disease burden from these infections can be heavy: the report notes mortality rates ranging from 5 to 30 percent. and there are no approved treatments for arenavirus infections.. For Junin virus, a vaccine is licensed in Argentina, and it may also provide some protection against Machupo virus.
A key question for epidemiologists is not just whether these viruses exist in rodent populations. but where those populations might end up as the climate changes.. Pranav Kulkarni. a veterinary epidemiologist at the University of California. Davis’s Weill School of Veterinary Medicine. says farmworkers in areas with infected rodents are typically at highest risk.. But climate-driven shifts in suitable habitat could move rodents—and the viruses they carry—into new regions with different levels of preparedness.
To explore that possibility. Kulkarni and colleagues used computer simulations that combined habitat suitability for six rodent species known to carry one of three arenaviruses with projections of future climate and with population density.. The modelled outcome was a changing risk landscape: the researchers found that the risk of viral transmission from rodents to people rises over the next 20 years in parts of the continent that are not currently at risk.
The projected spread is virus-specific.. Guanarito virus. the simulations suggest. is currently found in central Venezuela. but by 2060 it could spread to parts of Colombia. Guyana. Suriname and Brazil.. For Junin virus. the study indicates a shift from grasslands in Argentina toward other regions of Argentina. as well as Paraguay and Bolivia.. Machupo virus, currently associated with Bolivia, could in future also infect people in Brazil, Paraguay and Peru.
Disease ecologist Greg Glass of the University of Florida. Gainesville. who was not involved in the research. said the maps could help others plan the next steps.. “It allows folks going forward to use these maps to set up studies to go see if these species are there or not. ” he said.. But he also cautioned that verifying the predictions is crucial. because simulations can sometimes suggest circulation in areas where the virus is not actually present.. In his view, missing that distinction could lead to serious mistakes, including avoidable loss of life.
The simulations point to more than just temperature.. The study credits shifts in precipitation—alongside temperature changes—and highlights that human activities such as agriculture and urbanization can also influence rodent movement and the likelihood of contact between people and infected animals.. Still. Kulkarni emphasized that the calculations were focused on long-term changes. rather than the day-to-day fluctuations that can occur within seasons.
“What we would really like to do is look at short-term changes in weather. short-term changes in certain climate disruptions and how that affects risk from week to week or month to month. ” Kulkarni said.. That distinction matters because outbreaks can accelerate quickly when conditions align. and public health response often depends on signals that can be tracked in near real time.
The idea that climate change is already influencing some rodent-borne diseases is not purely theoretical.. During a May 7 news briefing. Carlos del Rio. a virologist and infectious diseases physician at Emory University in Atlanta. said hantavirus cases are on the rise in Argentina and that climate change is a key driver.. He noted that Argentina is becoming more tropical. a shift that could affect where rodents thrive and how often people come into contact with them.
The new arenavirus modelling also connects to the larger rodent-transmitted virus ecosystem.. Kulkarni said some of the rodents included in the study can transmit hantaviruses as well as arenaviruses.. The yellow pygmy rice rat, for example, transmits not only Junin virus but also some hantavirus strains.. While it is not known as a reservoir of the specific Andes hantavirus strain linked to the cruise ship incident. the finding underscores how range shifts could potentially expand the set of pathogens in a given place.
Del Rio framed the issue as a broader infectious disease reality: climate change is already reshaping the environment in ways that can affect how infections spread.. In that context. the new study’s risk maps are less a prophecy than a set of testable predictions—tools researchers can use to look for rodent reservoirs in locations the models suggest could become newly suitable.
For public health, the central worry is timing and visibility.. Kulkarni said that arenavirus diseases may not be on the radar of officials in areas that have not previously experienced outbreaks.. If climate and land-use change push infected rodents into new regions. that preparedness gap could widen just as populations face new exposure pathways.
Even as the research emphasizes future projections. it also sets an agenda for what needs to happen next: confirming whether predicted rodent distributions and virus circulation match real-world conditions. and refining the models to capture short-term weather disruptions as well as long-term climate trends.. If those steps succeed, the maps could help target surveillance earlier—before a regional shift turns into a high-impact outbreak.
arenavirus spread South America rodent-borne viruses climate change hemorrhagic fever disease ecology