What is Hantavirus Pulmonary Syndrome?

Hantavirus pulmonary syndrome (HPS) is a serious respiratory disease transmitted by infected rodents through urine, droppings or saliva. Humans can contract the disease when they breathe in aerosolized virus.

HPS was first recognized in 1993 and has since been identified throughout the United States. Although rare, HPS is potentially deadly.

Who gets Hantavirus Pulmonary Syndrome?

Anyone who comes into contact with rodents that carry hantavirus is at risk of HPS. Rodent infestation in and around the home remains the primary risk for hantavirus exposure. Even healthy individuals are at risk for HPS infection if exposed to the virus.

How does the disease spread?

In the United States, Hantavirus infection is usually spread by inhaling the virus, which is in the droppings, urine and saliva of infected rodents. Although uncommon, the virus can also be passed to humans through a rodent bite.

In Southern Nevada the common deer mouse (Peromyscus maniculatus) appears to be responsible for the spread of the disease at elevations above 5,000 feet. About 12 percent of the Deer mice that have been tested were found to be infected with the virus.

Other rodents including the cactus mouse, pinon mouse, brush mouse, canyon mouse, and western harvest mouse may also be infected with this virus but in much lower numbers.

The virus does not make rodents sick, but people who come into close contact with rodents may get sick. Even though not all rodents have the virus, it is difficult to properly identify mice; so all rodents should be avoided.

People may get sick when they touch or breathe dust from where there are rodent droppings (feces) or urine. Insect bites will not make you sick and you will not get HPS from another person.

What are the symptoms?

People who are sick from HPS may at first think they have the flu. The difference is that with this virus the breathing problems become worse, the lungs fill with fluid which may cause the breathing to stop and the person to die. The fatality rate is approximately 50 percent.

Early symptoms include:

• Fatigue
• Fever
• Muscle aches (especially in the thighs, hips, back and sometimes the shoulders)

About half of HPS patients also experience the following symptoms:

• Nausea
• Vomiting
• Diarrhea
• Abdominal pain
• Headache
• Dizziness
• Chills

Late symptoms begin four to 10 days after initial phase of illness and include:

• Coughing
• Shortness of breath
• Tightness around chest

Less common symptoms include:

• Earache
• Sore throat
• Runny nose
• Rash

How soon do symptoms appear?

The incubation period is not well known due to the small number of HPS cases. Based on limited information, it appears symptoms may develop between one and five weeks after exposure.

What is the treatment for Hantavirus Pulmonary Syndrome?

There is no specific treatment, cure or vaccine for HPS. Persons with severe breathing problems are often placed on oxygen and a ventilator. If a person has been around rodents and have symptoms of fever, deep muscle aches and severe shortness of breath they should see a doctor immediately.

What can be done to prevent infection from the virus?

Rodent control in and around the home remains the primary strategy for preventing hantavirus infection.

General Precautions

• Reduce the availability of food sources and nesting sites used by rodents inside your home.
• Keep food (including pet food) and water covered and stored in rodent-proof metal or thick plastic containers with tight-fitting lids.
• Store garbage in rodent-proof metal or thick plastic containers with tight-fitting lids.
• Wash dishes and cooking utensils immediately after use and remove all spilled food.
• Dispose of trash and clutter.

Activities that should be avoided are:

• Farming around rodent-infested areas
• Using rodent-inhabited buildings
• Cleaning barns or outbuildings infested with rodents
• Disturbing rodent nests and burrows while hiking or camping

Prevent rodents from entering the home:

• Use steel wool or cement to seal, screen, or otherwise cover all openings into the home that have a diameter of 1/4 inch or larger.
• Place metal roof flashing as a rodent barrier around the base of wooden, earthen, or adobe dwellings up to a height of 12 inches and buried in the soil to a depth of 6 inches.
• Place 3 inches of gravel under the base of homes or under mobile homes to discourage rodent burrowing.
• Reduce rodent shelter and food sources within 100 feet of the home.
• Use raised cement foundations in new construction of sheds, barns, outbuildings, or woodpiles.
• When possible, place woodpiles 100 feet or more from the house and elevate wood at least 12 inches off the ground.
• Store grains and animal feed in rodent-proof containers.
• Near buildings, remove food sources that might attract rodents or store food and water in rodent-proof containers.
• Store hay on pallets, and use traps or rodenticide continuously to keep hay free of rodents.
• Do not leave pet food in feeding dishes.
• Dispose of garbage and trash in rodent-proof containers that are elevated at least 12 inches off the ground.
• Haul away trash, abandoned vehicles, discarded tires, and other items that may serve as rodent nesting sites.
• Cut grass, brush, and dense shrubbery within 100 feet of the home.
• Place spring-loaded traps at likely spots for rodent shelter within 100 feet around the home, and use continuously.

Clean-up Procedures

• Any area where you see rodent activity such as dead rodents or rodent droppings (feces) and urine should be thoroughly cleaned.
  • Use wet mopping or wet cleaning methods to carefully remove rodent droppings (feces) and urine from occupied buildings.
    • Avoid creating dust or aerosol from rodent droppings (feces) and urine.
  • Wet with disinfectant before cleaning, and use wet mopping or cleaning techniques.
  • Do not use a vacuum cleaner or a broom because they will create airborne particles and dust.
  • Wear rubber gloves, long-sleeved clothing, and a dust mask.
  • Always wash hands with soap and warm water afterward.
• Use 3 tablespoons of household chlorine bleach to a gallon of water as a disinfectant.
  • You may also use Lysol or other cleaners that say disinfectant on the label and have phenol on the list of ingredients.
  • Apply the disinfectant to the mouse droppings (feces) and urine and all areas where rodents have been at least 30 minutes before cleanup to give it a chance to work.
  • Dispose of droppings (feces) by burial in double plastic bags.
    • If droppings have been treated properly with a sanitizer, they can be double bagged and disposed in the regular trash bin.
• Do not touch dead rodents.
  • Wet dead rodents and rodent nests with disinfectant, allowing at least 30 minutes for disinfectant to work before removing.
  • Dispose of rodent bodies by either picking them up with a tool and placing in a double plastic bag, which is then sealed or placing hand into a double plastic bag, picking up rodents, then reversing the bag back over the rodents and sealing.
  • Dispose of by burial or in the trash.
  • Wash gloved hands in a general household disinfectant and then in soap and water.
  • Wash bare hands after removing gloves.

Guidance for Hikers and Campers

• Stay away from rodents and rodent burrows or dens such as pack rat nests.
• Do not use cabins or other enclosed shelters that have rodents or rodent droppings (feces) and urine until they have been properly cleaned and disinfected.
• Do not pitch tents or place sleeping bags near rodent droppings (feces) or burrows.
  • Also do not camp near places where rodents may find shelter such as garbage dumps or wood piles.
    • If possible, do not sleep on the bare ground.
  • Use a cot with the sleeping surface at least 12 inches above the ground.
  • Use tents with floors.
• Keep food in rodent-proof containers.
• Promptly bury all garbage and trash, or discard in covered trash containers.
• Use only bottled water or water that has been disinfected by filtration, boiling, chlorination or iodination for drinking, cooking, washing dishes, and brushing teeth.

Special Precautions

Homes of people infected with HPS or buildings with a great many rodents or a lot of rodent droppings (feces) need to be very carefully cleaned. You should contact your health department for specific instructions.

Southern Nevada Health District
Environmental Health Section
(702) 759-1633

Nevada State Health Division
Bureau of Health Protection Services
(775) 687-4750

Washoe County District Health Department
Vector Control Program
(775) 328-2434

Where can I get more information?

For questions about the medical aspects of HPS, contact your doctor or the Southern Nevada Health District, Office of Epidemiology at (702) 759-1300.

For questions about rodents, rodent contamination clean-up procedures and prevention techniques, contact the Southern Nevada Health District, Environmental Health Division at (702) 759-1633.