Gene Hackman's wife Betsy Arakawa died from hantavirus. But what is it?

(NEXSTAR) – A medical examiner confirmed Friday that Betsy Arakawa, a concert pianist and wife of Gene Hackman, died of illness caused by hantavirus.

Arakawa and Hackman, along with one of their dogs, were discovered dead in their Santa Fe, New Mexico home Feb. 26.

While Arakawa, 65, died of hantavirus pulmonary syndrome, Hackman, 95, did not test positive for the rare disease. Authorities said Hackman suffered from severe heart disease with as well as Alzheimer's disease.

What is hantavirus?

Hantavirus is spread mainly by rodents, not from one person to another. According to the Centers for Disease Control and Prevention (CDC), humans can contract the virus from mouse or rat urine, droppings and saliva. In rare cases, it can spread through a bite or scratch.

In the U.S., hantavirus is usually spread by the deer mouse, according to the CDC.

In the Western Hemisphere hantavirus can cause hantavirus pulmonary syndrome, meaning it affects the lungs. Symptoms usually surface between one and eight weeks after contact with an infected rodent and can include fatigue, fever, muscle aches, headaches, dizziness, chills and abdominal problems.

After four to 10 days, late symptoms such as coughing, lungs filling with fluid and shortness of breath begin.

The CDC says roughly 38% of people who experience respiratory symptoms die from hantavirus.