Hantavirus Pulmonary Syndrome (HPS)

What's the Problem?

Hantavirus pulmonary syndrome (HPS) is a life-threatening disease that is caused by some hantaviruses. HPS starts out with fever, fatigue, and muscle aches. Four to ten days later, symptoms include cough and shortness of breath. As one survivor put it, there is a sensation of "a tight band around my chest and a pillow over my face" as the lungs fill with fluid.

Only certain mice and rats can carry hantaviruses that cause HPS. Infected rodents spread the viruses through their urine, droppings, and saliva. People most often get the disease by breathing in air contaminated with virus particles. The air can become contaminated when fresh urine, droppings, or nesting materials are stirred up.

HPS is often fatal: 37% of patients in the United States have died. Fortunately, the disease is relatively rare; only 326 cases had been reported in the United States as of August 2002. No drug is available to prevent or cure HPS. However, early intervention that includes supportive clinical treatment increases the chances of survival.

Who's at Risk?

The disease can affect men, women, and children from all races throughout the United States, Canada, and Central and South America. HPS can develop in people who are in excellent health and is not limited to those with lung disease or other health problems. Risky activities include cleaning seasonally closed buildings like sheds or cabins, cleaning around the home if there are mice and rats living there, or camping in trail shelters or other areas where mice and rats live. Stirring up rodent droppings or nesting materials is especially risky.

Can It Be Prevented?

Preventing HPS requires avoiding contact with mice and rats. The best method of prevention is to keep mice and rats out of the home. Using snap traps and sealing up holes where rodents can enter the home can do this. A mouse or rat can enter a building through a very small opening. It is also important to make the home, workplace, or campsite unattractive to mice and rats by keeping food (including pet food) in covered containers and getting rid of trash that could be used as nesting places. Additionally, when cleaning up mice and rat urine, droppings, or nesting materials,safe clean-up methods should be used. These methods include wearing gloves and using a disinfectant and not sweeping or vacuuming as this can stir up dust.

The Bottom Line

• Before cleaning, ventilate rodent-infested areas that have been closed up. Wear gloves. Do not stir up dust by sweeping or vacuuming droppings or nesting materials; instead, spray droppings with disinfectant and pick up material with paper towels.
• If a mouse or rat is caught in a snap-trap, the carcass should be sprayed with disinfectant and placed in a double plastic bag.
• Be aware of the early symptoms of HPS – fever, fatigue, and muscle aches without sore throat or runny nose – that can develop into a life-threatening respiratory illness. Early diagnosis increases chances of survival.
• Make buildings rodent-proof. Look for openings around pipes, windows, and doorframes; block openings with caulking and other materials. Eliminate things that attract mice and rats. Keep pet food covered, store food in containers, and use garbage containers with tight-fitting lids.

Case Example

In April, newly wed Barbie and Keith buy a quaint older home in rural Washington State. The house was on the market for several months and has been vacant since the previous November. Vacant of people, that is. As the cool weather moved in, so did some nearby deer mice. An old sofa cushion in the basement made a cozy place to nest and the grease left in and around the stove made a good meal. All winter long, the mice scurried about, leaving droppings and urine, some of it infected with a hantavirus. By springtime, lots of mice are excreting virus, particularly when they are disturbed. Soon after the purchase, Barbie and Keith scheduled a weekend for cleanup. Before cleaning, they open all the doors and windows and let the house air out for an hour. They spray down the droppings with a disinfectant before sweeping. They check under the sink to see if they need to seal openings around the pipes where mice could get in.