The first Douglas County case of hantavirus in five years was reported by Carson City Health and Human Services on Wednesday.

A man under 50 years of age was hospitalized after inhaling or coming in contact with rodent droppings, urine, or nesting material disturbed during household renovations in the weeks prior to symptom development. The investigation is ongoing.

It’s the fifth reported case of the virus in the eastern Sierra with a recent case in Washoe County and three fatalities in Mammoth Lakes.

About one-third of people with Hantavirus infections die, according to Mono County Public Health Officer Dr. Tom Boo.

“The occurrence of three cases in a short period has me worried, especially this early in the year,” he said in April in the announcement of the third death. “Historically, we tend to see Hantavirus cases later in the spring and in the summer. We believe that deer mouse numbers are high this year in Mammoth (and probably elsewhere in the Eastern Sierra). An increase in indoor mice elevates the risk of hantavirus exposure.”

The three Mammoth deaths don’t appear to be related to the usual activities associated with the virus.

“As far as we know, none of these deceased individuals engaged in activities typically associated with exposure, such as cleaning out poorly ventilated indoor areas or outbuildings with a lot of mouse waste,” Boo said. “Instead, these folks may have been exposed during normal daily activities, either in the home or the workplace. Many of us encounter deer mice in our daily lives and there is some risk. We should pay attention to the presence of mice and be careful around their waste.”

Mono County has recorded 27 cases since it was first reported here in 1993, the most in the State of California. Twenty-one of these infections affected county residents, and six occurred in visitors who were infected in Mono.

“People get infected with Hantavirus through contact with the feces, urine, or saliva of infected deer mice,” Boo said. “Most often this happens by inhaling contaminated particles in the air, although getting waste in your mouth from contaminated hands can cause infection too.”

The incubation period after infection is usually two or three weeks but can range from one to more than seven weeks, after which illness typically begins as a nonspecific flu-like illness with fever, headache and body aches, also often with gastrointestinal symptoms such as nausea, vomiting, diarrhea and occasionally abdominal pain. These early symptoms are usually not mild. Muscle aches, for example, are often severe.

“Typically, there is no cough in this early phase, and the presence of cough, runny nose or sore throat in the first day or two points more to common respiratory viruses such as flu or COVID,” Boo said. “Hantavirus often, though not always, progresses to involve the lungs after a few days, at which time a cough develops. Shortness of breath is a worrisome sign of worsening disease. This is Hantavirus Pulmonary Syndrome and it frequently worsens rapidly, with potential death within a day or two.”

Boo said the only source of hantavirus in the area is from deer mice. It does not spread between people and other rodents do not carry it.

“Hantavirus pulmonary syndrome is a respiratory infection that mainly occurs from breathing in particles of infected rodent droppings, urine, or saliva, and can be fatal,” according to the agency that handles health reporting for Douglas County. “According to the Centers for Disease Control & Prevention (CDC), 38 percent of people who develop respiratory symptoms may die from the disease.”

The virus has been in the news after it was determined to be what killed Gene Hackman’s wife and led to the actor’s demise.

Prevention

• Do not sweep or vacuum the area with urine, droppings, or nesting material.
• A solution of 1 part bleach to 9 parts water should be used when cleaning urine and/or droppings (1.5 cups bleach to 1 gallon of water).
  • Spray the solution on areas with rodent droppings and leave for five minutes before wiping the area with disposable paper towels or cloth. Dispose of the waste in a sealed plastic bag.
• Wear gloves (i.e., latex, vinyl, rubber) and a face mask to avoid touching or breathing in viral particles.
• Identify areas where mice are, plug openings, and set traps; a deer mouse can fit through an opening the size of a nickel. Food should be stored in rodent-proof containers.