The increased rainfall and warmer temperatures associated with a super El Niño could lead to a surge in deer mouse populations, particularly in rural and agricultural areas of the U.S. Southwest, including Arizona, Colorado, New Mexico, and Utah. This raises the risk of human exposure to hantavirus, which is transmitted through contact with infected rodent droppings, urine, or saliva. Enclosed spaces such as cabins and sheds are particularly high-risk areas. While hantavirus infections remain rare, the disease is often fatal if contracted. Public health experts emphasize that even a small increase in rodent populations could elevate the likelihood of sporadic infections, making preventive measures critical.