Betsy Arakawa, the wife of Gene Hackman, died from the effects of hantavirus, a rare disease often caused by contact with droppings from infected rodents.

Hantavirus does not spread among people in the cases found in the United States. It can be transmitted through rodent saliva. But it is most commonly transmitted by breathing in particles of dried deer mouse droppings or urine.

At first, hantavirus causes flulike symptoms, including fever, chills, body aches and headaches. But as the disease progresses, respiratory symptoms develop and patients can experience shortness of breath and then lung or heart failure.

Here is what to know about hantavirus.

What is hantavirus?

Hantavirus refers to a family of viruses that are carried by rodents. It is often transmitted to humans by inhaling particles from dried mouse droppings. In North America, Sin Nombre virus is the most common form of this virus, said Sabra L. Klein, a professor at the Johns Hopkins Bloomberg School of Public Health.

As of the end of 2022, 864 cases of hantavirus disease had been reported in the United States since surveys of such cases began in 1993, according to the Centers for Disease Control and Prevention. The “classic” case of hantavirus is contracted by someone who has visited a rural cabin that has a rodent infestation, said Emily Abdoler, a doctor and assistant professor of medicine at the University of Michigan Medical School.

Hantavirus has flulike symptoms at first.

Hantavirus can cause flulike symptoms that appear one to eight weeks after exposure to droppings from an infected rodent, according to Dr. Heather Jarrell, New Mexico’s chief medical examiner. Later, patients often experience shortness of breath and then lung or heart failure.

The mortality rate from the hantavirus strain in the southwestern United States is between 38 and 50 percent, Dr. Jarrell said. The strain in the region cannot be transmitted from person to person, she said.

New Mexico is no stranger to hantavirus.

In the United States, hantavirus is most commonly found in the Four Corners region — Utah, Colorado, Arizona and New Mexico — according to Dr. Abdoler.

New Mexico has recorded from one to seven hantavirus infections each year for the past five years, according to Dr. Erin Phipps, a veterinarian at the New Mexico Department of Health.

Most people get infected around their home or workplace, she said. On the property east of Santa Fe where Mr. Hackman and Ms. Arakawa lived, health officials found signs of rodent entry in some structures, although little risk of exposure to the virus in the main residence.

It is not clear when Ms. Arakawa began to feel ill, Dr. Jarrell said.

How do I prevent hantavirus?

Although there are antivirals that can help manage symptoms, there are no cures specifically for hantavirus, Ms. Klein of Johns Hopkins said. That’s why prevention is important.

If you live in an area where hantavirus-infected rodents are known to roam, clean any droppings with a wet paper towel. Do not use a vacuum or a broom, which can stir up the aerosols from the excrement.

Use gloves and a tightfitting N95 mask in a well-ventilated space. People should spray the area with a bleach solution or a commercial disinfectant and let it sit for five minutes. Then they should clean the area with paper towels, tossing them in a trash can that closes tightly, Dr. Phipps said.

Treatment of hantavirus in the intensive care unit may include intubation and oxygen therapy, fluid replacement and medications to support blood pressure. Sometimes antiviral drugs are used.