According to the Montana Department of Public Health and Human Services (DPHHS), Montana has reported 46 cases of hantavirus infection since 1993. Eleven of those cases have resulted in deaths. The deer mouse and white-footed mouse are responsible for spreading hantavirus in Montana.

The most common method of transmission is people inhaling airborne rodent urine, fecal, or saliva particles. It can be contracted when dried materials that contain rodent feces are disturbed and that material contacts broken skin, mucus membranes (i.e., eyes, nose, etc.), or is ingested in contaminated water or food. In rare instances, people bitten by rodents have become infected. Hantavirus cannot be transmitted through human-to-human contact.

Someone exposed to hantavirus might develop a hantavirus infection, which could progress to a severe disease called hantavirus pulmonary syndrome (HPS).

Signs and symptoms of hantavirus can include:

  • Fever
  • Chills
  • Headache
  • Nausea, vomiting, and/or diarrhea
  • Muscle aches in large muscle groups (thighs, hips, back, and sometimes shoulders)
  • Fatigue

Signs and symptoms of HPS (all of the above as well as):

  • Coughing
  • Shortness of breath

Symptoms may appear one to eight weeks after contact with the virus. There is no specific treatment for hantavirus, and patients receive supportive care. If you experience any of these symptoms and have been in a location where you may have come in contact with rodents, seek medical attention immediately. Tell your healthcare provider you have been in contact with rodents.

The CDC and DPHHS have a three-step process to prevent hantavirus: seal up, trap up, and clean up.

SEAL UP

  • Seal holes inside and outside of residences to keep rodents out
  • Store food items in sealable containers to prevent rodent entry

a hole in a house created by mice

Mouse hole and droppings in a basement.

Photo credit: Liz Kasameyer

TRAP UP

  • Trap rodents around the residence to help reduce rodent populations
  • Consult with an exterminator if there is a serious rodent infestation

a snap mouse trap in an attic

Baited exterminator snap mouse trap in residential attic.

Photo credits: Adobe Stock

CLEAN UP

  • Never sweep or vacuum areas that have potential rodent infestations, as this can result in the inhalation of the virus.
  • Buildings or areas that have been out of use for an extended period of time or show signs of rodent infestation should be aired out by opening windows and doors to promote air circulation for at least 30 minutes. People should leave the area during the ventilation process.
  • Wear rubber, latex, or vinyl gloves when cleaning areas potentially infested or contaminated with rodents.
  • Spray potentially contaminated surfaces with a disinfectant such as a 1 percent (1:100 dilution) bleach solution and wipe the area clean. Soak heavily infested or contaminated areas with a disinfectant such as a 10 percent (1:10 dilution) bleach solution and wipe the area clean.

the remains of a mouse nest made of housing insulation

Mouse nest and droppings in the broiler area of a stove.

Photo credit: Johns Hopkins School of Public Health, Bugwood.org

For more information about hantavirus, its symptoms, and how to prevent contracting it, visit the CDC’s Hantavirus Prevention website.

This article is adapted and updated from the Lives and Landscapes 2016 spring/summer issue, written by Mary Anne Keyes and Tracy Mosley.