Hanta sign


Mono County Resident Dies of Hantavirus Infection

Un Residente del Condado de Mono Muere de Infección por Hantavirus

Be Hantavirus Aware on the Eastside

Key points

  • Hantavirus is an uncommon but deadly disease in the Eastern Sierra.
  • The Sierra region of California is a hantavirus hotspot.
  • Carried by deer mice, people can catch it from exposure to mouse waste.
  • Most people who get hantavirus were exposed by cleaning up mouse waste in a closed room or building.
  • Airing out a building or room that has been closed-up for some time AND using disinfectant (such as Lysol or bleach) on mouse waste reduces the chance of getting hantavirus (see more information below).


One or two people in Mono County usually get sick with hantavirus each year.  People on the Eastside should know about it and how to avoid it.  Hantavirus infection can occur at any time of year but is more common in the spring and summer.   It is deadly, and statistically one of three people with hantavirus die.  It is a virus that humans can catch from infected deer mice. The virus is found in mouse feces, urine and saliva.  People usually catch hantavirus by breathing in the germs when mouse waste gets stirred up by sweeping or vacuuming, and the germs get in the air.  The chance of breathing in these germs is highest in closed, poorly ventilated rooms and buildings.  Try to keep mice out of your home and other buildings and if you find a mess left by mice indoors, or in your vehicle, know how to safely clean it up.

Hantavirus symptoms

Weeks usually pass after exposure to the virus before any illness begins. Hantavirus begins with fever and achy muscles, like the flu, usually lasting some days. Headaches and dizziness with the fever and body aches are very common.  Often there is also diarrhea, vomiting or abdominal pain (about half of people with hantavirus).  Early on it is difficult to tell it apart from other infections with flu-like symptoms.  Cough may begin after some days of being sick, followed by trouble breathing, as the lungs and heart are affected. There is no medication to cure hantavirus and survival may depend on intensive care.  Hantavirus tests can be drawn locally but blood is sent to larger out of the area labs, so results are delayed.


Taking some simple precautions around mice will reduce the chance of getting this disease:


  • Keep rodents out of houses, sheds and barns as much as possible.
  • Experts recommend rodent removal (trapping) days before cleaning.
  • Open-up doors and windows at least a couple hours before clean-up or create cross ventilation in closed, poorly ventilated, mouse-infested building (like sheds, barns, basements).
  • Do not dry vacuum or sweep.
  • Wear rubber gloves to handle rodents, living or dead.
  • Wear goggles if infestation is heavy.
  • For very heavy infestations power respirators with HEPA filters (either half-mask air purifying or powered air purifying respirators) are recommended (dust masks do not provide protection).
  • Wet down rodent nests and other contaminated areas with disinfectant like bleach or Lysol. Bleach must be mixed up fresh, with at least one-part bleach to 10 parts water. Most household disinfectants work well.
  • Allow disinfectant to stand for at least 5 minutes before mopping or cleaning up with paper towels.
  • Promptly dispose of cleaning materials and wash hands and clothes.


  • Some people have caught hantavirus from vehicles that were infested with mice.
  • Mice are more likely to get into a vehicle and build nests when it sits unused for a period time.
  • If you notice rodent droppings or nesting materials in your car, or if seeds or nesting materials blow out of your car vents when you turn on the fan, you should remove any mice that are present and the waste left behind using the same precautions as in buildings.
  • Again, work in an open well-ventilated space, wear gloves, and use disinfectant.


  • Employers should make sure that staff know what they need to know to reduce the chance of getting hantavirus.


  • The risk of hantavirus from exposure to mouse waste outdoors is low.

More information