Old wounds reopened

Extreme weather phenomena, such as droughts and episodes of intense rainfall in recent years, are also fueling the trend, according to experts.

Temperature rises trigger changes in the ecosystem that affect the presence of the long-tailed mouse, the main carrier of the virus in Argentina and Chile.

"These rodents are better able to adapt to climate changes, which could facilitate the higher number of cases we are seeing," said Eduardo Lopez, an infectious disease specialist and adviser to the Argentine government during the Covid-19 pandemic.