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A little over a month ago award winning actor Gene Hackman and his wife Betsy Arakawa were found dead in their Santa Fe home, and it was determined that his wife died from a rare Hantavirus infection. Over the weekend, the Mono County (California) Health Department announced their 3rd recent death from the virus.
Hantavirus is a collective term for a group of viruses in the Bunyaviridae family – hosted by various types of rodents - that vary in distribution, symptomology, and severity around the world.
Scientists have identified dozens of viruses within the genus Hantavirus (named after the Hantaan River of Korea) from all around the world, with mortality that varies from 1%-2% for some varieties (i.e. Seoul Virus, Puumala Virus) to more than 30% for the North American Sin Nombre and South American Andes Virus.
The following press release was posed on the Mono County Facebook page. I'll have more on past outbreaks and prevention when you return.
MONO COUNTY HEALTH AND HUMAN SERVICES
Public Health Division
FOR IMMEDIATE RELEASE
Third Hantavirus-Related Death Confirmed in Mono County
MONO COUNTY, Calif. (April 3, 2025) - Mono County Public Health has confirmed a third death due to Hantavirus in the Town of Mammoth Lakes. Hantavirus is a serious and often fatal illness which people can get through contact with infected deer mouse droppings, urine, or saliva. Deer mice are widespread in the Eastern Sierra region.
"A third case of Hantavirus Pulmonary Syndrome (HPS), each of which has been fatal, is tragic and alarming, said Dr, Tom Boo, Mono County Public Health Officer.
"We don't have a clear sense of where this young adult may have contracted the virus. The home had no evidence of mouse activity We observed some mice in the workplace, which is not unusual for indoor spaces this time of year in Mammoth Lakes. We haven't identified any other activities in the weeks before illness that would have increased this person's exposure to mice or their droppings.
We 've been aware of this suspected case for some weeks, but it has taken time to obtain testing. The occurrence of three cases in a short period has me worried, especially this early in the year. Historically, we tend to see Hantavirus cases later in the spring and in the summer. We've now gone about a month without any additional suspect cases, but remain concerned about the increase in activity.
We believe that deer mouse numbers are high this year in Mammoth (and probably elsewhere in the Eastem Sierra). An increase in indoor mice elevates the risk of Hantavirus exposure. Therefore, it is crucial to take precautions and follow the prevention steps outlined below I want to emphasize that 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. 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 some risk. We should pay attention to the presence of mice and be careful around their waste "
Ongoing Investigation
Each Hantavirus case is investigated by local and state public health officials. Each of our recent cases lived and worked in Mammoth Lakes and experienced illness beginning in February_ When a person has died, we can only talk to people who knew them about the places they were and things that they did in the weeks before they got sick We know that one person had numerous mice in their home.
No evidence of mice was found in the other two homes. In all three cases there was some evidence of mice in places they had worked, but no major infestations were found. Investigators did note that one person did some vacuuming in one or more areas where investigators later found mouse droppings. Vacuuming can aerosolize the virus from mouse waste spreading the virus through the air and lead to infection.
Mono County has now recorded 27 cases since it was first reponed 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_ Hantavirus more commonly occurs in the late spring or summer, so three cases this early in the year is strikingly unusual,
(Continue . . )
Over the summer of 2012 we followed a months-long outbreak among visitors to California's Yosemite National Park (see here, here, and here). In November of that year, in MMWR: Yosemite Hantavirus, the CDC's investigation cited 10 cases and 3 deaths linked to that outbreak.
Ages ranged from 12 years to 56 years; four were female. Nine patients had typical symptoms of HPS, and one lacked respiratory symptoms; three died.
Most Hantavirus cases are sporadic, but occasionally we see clusters. Eight years ago, Washington State Reported their 5th Hantavirus Case Of 2017. Exposure is often linked to cleaning out sheds and garages in the late spring and summer, so the cluster in February in Mono County is a bit of an outlier.
The CDC has a 20-page PDF guide on reducing exposure risks.
While far less deadly, in 2017 we followed a multi-state outbreak of a milder `Seoul' Hantavirus linked to the sale and distribution of pet rats (see CDC HAN Advisory: Seoul Virus Outbreak Associated with Home-based, Rat-breeding Facilities in Wisconsin and Illinois).
A year later, the CDC's MMWR reported,
In January 2017, CDC confirmed recent, acute Seoul virus infection in both patients. An investigation was conducted to identify additional human and rat infections and prevent further transmission. Ultimately, the investigation identified 31 facilities in 11 states with human and/or rat Seoul virus infections; six facilities also reported exchanging rats with Canadian ratteries.
Testing of serum samples from 183 persons in the United States and Canada identified 24 (13.1%) with Seoul virus antibodies; three (12.5%) were hospitalized and no deaths occurred. This investigation, including cases described in a previously published report from Tennessee (1), identified the first known transmission of Seoul virus from pet rats to humans in the United States and Canada. Pet rat owners should practice safe rodent handling to prevent Seoul virus infection (2).
The list of rodent-borne zoonotic diseases is long, and - based on recent reports with H5N1 (see here, here, and here) coronaviruses (see here and here) and Hepatitis (see here) - only seems to be getting longer.
