90-Second Read: What Arizona should understand about Hantavirus

Though the case is unrelated to the Hantavirus outbreak on a cruise ship earlier this year, it highlights the need for caution for the rare, but deadly disease. Question: How concerned should Arizonans be about Hantavirus right now? A: In 1993, the Southwest's Four Corners Hantavirus outbreak resulted in 33 cases and 17 deaths. Earlier this month, Hantavirus made local headlines following a confirmed death due to the rodent-borne virus in Mohave County.

A: The Sin Nombre strain of Hantavirus is tied to a particular kind of mouse called a deer mouse. Q: What is the connection between El Niño and Hantavirus outbreaks? Q: Does this reveal something about the broader relationship between climate, wildlife and human health? This mouse is found throughout the West, and particularly in Northern Arizona.

The result is more rodents carrying Hantavirus and a greater chance of human exposure. That's why Hantavirus risk tends to increase after strong El Niño events. Many of the diseases that affect people originate in nature, so understanding how pathogens circulate in the environment and among animals helps us better understand their impacts on human health. The potential link between El Niño and increased Hantavirus risk is a good example.

That outbreak followed a strong El Niño in 1992, which brought unusually heavy rainfall to the region. While we can't know exactly what will happen, we can anticipate the same chain of events: increased rainfall, larger rodent populations, more infected rodents and potentially a higher risk of human cases. We're most at risk of coming in contact with wild mice and their droppings, which spreads the disease, in garages, sheds and the like.