Hantavirus in the Americas 2025: More than a quarter of the cases were fatal
Hantaviruses are a group of viruses that spread to humans through exposure to rodents.
People typically develop hantavirus infection from exposure to the infected urine, saliva, or droppings of rodents, usually rats and mice (primarily zoonotic).
In the Western Hemisphere, the Pan American Health Organization (PAHO) reported a total of 229 hantavirus cases and 59 deaths in eight countries in the Americas Region, mainly in the Southern Cone in 2025- Argentina, Brazil, Bolivia, Chile, Panama, Paraguay, the United States of America, and Uruguay.
This is a case fatality rate of nearly 26 percent.
According to PAHO, two countries reported significant increases in incidence, particularly Bolivia and Paraguay, the latter associated with an outbreak with occupational exposure, reaching values that double or exceed those reported in recent years. For their part, Argentina and Brazil was observed an increase in lethality.
Lets look at the eight countries:
Argentina reported 66 confirmed cases of hantavirus pulmonary syndrome (HPS) and 21 deaths (32% CFR), about double the average lethality.
Brazil reported 20 confirmed cases and 11 deaths (55% CFR), also exceeding the average lethality in recent years.
Bolivia reported 48 confirmed cases and 11 deaths (22.9% CFR).
Chile reported 35 confirmed cases and seven deaths (20% CFR).
Panama reported 18 confirmed cases and no deaths.
Paraguay reported 27 confirmed cases and six deaths (22.2% CFR). 15 cases are linked to an outbreak associated with road activities in Mariscal Estigarribia.
Uruguay reported eight confirmed cases and one death (12.5% CFR).
. The United States reported seven confirmed cases and two deaths (case fatality rate 29%) have been reported in the following States: Arizona (n= 3), Colorado (n= 1), Nevada (n= 1), Washington (n= 1), and Wisconsin (n= 1).
Human-to-human transmission of Hantavirus, while extremely rare, has been documented almost exclusively with the Andes strain in Argentina and Chile. Notably, the virus can remain infectious in dried rodent excreta for over two weeks depending on environmental conditions. In my view, the 26% fatality rate highlights the urgent need for early diagnosis, as initial symptoms often mimic a simple flu before sudden respiratory collapse.