"Climate change is contributing to the conditions driving a rodent boom — dubbed a ratada — in Argentina."
"The hantavirus outbreak aboard the MV Hondius cruise ship has created a global public health crisis. But the driver of it is a rodent that weighs about an ounce, and climate shifts this year that have helped increase the odds of transmission.
Across the Southern Cone, researchers have long associated wetter years with explosive rodent population booms—known locally as ratadas—that can amplify hantavirus transmission. This year’s boom reflects a broader pattern of disease outbreaks shaped by climate change, environmental disruption, and a hyperconnected world.
“These are emerging diseases because the distribution of both the reservoirs and the viruses is expanding,” says Karina Hodara, a researcher at the Faculty of Agronomy at the University of Buenos Aires who studies hantavirus ecology. “Humans travel across continents in a matter of hours.”
The long-tailed pygmy rice rat is the common name for several species that live in Chile and Argentina that can harbor hantavirus. Each species is associated with different hantaviruses depending on geography.
It’s still unclear where the first passengers that got sick with the Andes virus contracted it. But the Patagonian long-tailed pygmy rice rat (Oligoryzomys longicaudatus), which inhabits southern Argentina and the woods and shrublands in Chile and weighs about one ounce, is the main reservoir of the only known hantavirus capable of spreading from rodents to humans and between humans. This person-to-person transmission “is precisely what makes outbreaks possible,” adds Raúl González Ittig, an expert in population genetics and evolution at the National University of Córdoba."
María de los Ángeles Orfila reports for WIRED May 20, 2026.
