Health District officials are investigating a suspected case of Hantavirus Pulmonary Syndrome (HPS) in a middle-aged Grant County resident. The individual is believed to have been exposed to contaminated deer mouse droppings while cleaning out their vehicle. According to the family, the ill individual is improving but is still hospitalized with respiratory failure from the illness that began the middle of April. Preliminary test results were positive for Hantavirus infection; confirmatory results are pending.

Deer mouse/CDC
Deer mouse/CDC

If confirmed, this case will be the first hantavirus case reported in Grant County in six years. In 2012, two Grant County residents died of HPS from unrelated incidents. On average, 1 to 5 confirmed Hantavirus cases are reported each year in Washington.

Seattle, hantavirus and an interesting transmission theory

Hantavirus Pulmonary Syndrome (HPS) is a rare illness caused by a virus found in the urine, droppings and saliva of infected rodents. In Washington State, deer mice are the only carriers of the virus.

A person can get HPS by breathing in particles contaminated with hantavirus. This can happen when dust from dried rodent urine, saliva, and droppings that contain hantavirus are stirred up in the air. People can also get infected by touching rodent urine, droppings, or nesting materials that contain the virus, and then touching their eyes, nose, or mouth. It’s also possible to get HPS from a rodent bite. The disease does not spread person-to-person. The greatest risk occurs when people enter enclosed areas with rodent infestation and poor air circulation, such as sheds and other outbuildings, cabins, building crawl spaces, vehicles and campers.

HPS illness usually begins one to six weeks after a person breathes in the virus. Early signs include fever, muscle aches, headaches, dizziness, chills, nausea, vomiting. As the disease gets worse, it causes coughing and shortness of breath and can lead to respiratory failure. People with hantavirus are usually hospitalized, and about one out of three people diagnosed with HPS have died. If you have been exposed to rodents or rodent infested buildings and have symptoms, see your doctor immediately and tell them about your possible rodent exposure.

How should rodent-infested areas be cleaned?  If you do have a rodent infestation, it’s important to take precautions when entering these spaces and during cleaning.

  •  Before entering rodent-infested spaces, “air-out” the space by opening multiple doors and windows for at least 30 minutes to allow fresh air to circulate. Leave the area while it is airing out.
  •  Wear rubber or plastic gloves. A dust mask may provide some protection against dust, molds, and insulation fibers, but does not protect against viruses. A properly fitted N-95 mask will offer better protection.
  • Do not vacuum, sweep, or otherwise stir up dust.
  • Thoroughly spray contaminated areas including trapped mice, droppings, and nests with a mixture of bleach and water: o Mix 1½ cups of household bleach in 1 gallon of water (or 1 part bleach to 9 parts water). o Soak area for 10 minutes, then remove all of the nest material, mice or droppings with damp paper towels and throw the paper towels in the garbage. o Mop or sponge the area with bleach solution.
  • Wash gloves with disinfectant or soap and water before taking them off. Remove the gloves, then wash hands with soap and water.
  • Steam clean or shampoo upholstered furniture, carpets and car interiors, and wash any bedding or clothing in hot water if you see any mouse or rat urine or droppings on them.
  • Areas with heavy infestation (piled up droppings, numerous nests and dead rodents) require extra precaution. Professional cleaning and/or pest control services may be needed.