Hantavirus is a group of viruses that are primarily transmitted to humans through rodents. These viruses belong to the family Hantaviridae and are typically associated with two main syndromes. Hantaviruses found in America are known to cause Hantavirus Pulmonary syndrome (HPS). Hantaviruses found in Europe and Asia may cause Hemorrhagic Fever with Renal Syndrome (HFRS). HPS is a severe, sometimes fatal, respiratory disease in humans caused by infection with hantaviruses. Anyone who comes in contact with rodents that carry hantaviruses is at risk of developing 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. 

HPS is the more severe form of hantavirus infection. Symptoms often progress rapidly and can include:  

• Fever: The infection typically starts with a high fever. 
• Muscle pain and fatigue: Muscle pain and fatigue are common early symptoms. 
• Gastrointestinal Symptoms: Some people may experience nausea, vomiting, abdominal pain, and diarrhea. 
• Respiratory Symptoms: As the disease progresses, respiratory symptoms develop and can include a dry cough and shortness of breath. 
• Severe Breathing Difficulties: In advanced cases, severe respiratory distress can occur, often requiring hospitalization and mechanical ventilation. 
• Fluid Accumulation in lungs: HPS can lead to fluid buildup in the lungs, making breathing very difficult. 

If you are experiencing any of the symptoms listed above, it is important that you see your healthcare provider immediately. Mention any potential rodent exposure you might have had to your healthcare provider. 

Diagnosing HPS in a recently infected individual can be challenging because the initial symptoms, such as fever, muscle pain, and fatigue, are easily mistaken for influenza. However, the presence of fever and fatigue along with a history of potential rural rodent exposure, combined with shortness of breath in an individual strongly indicates HPS. 

While there isn’t a specific treatment, cure, or vaccine for hantavirus infection, early recognition and medical care in an intensive care unit can improve patient outcomes. In such settings, individuals are intubated and provided oxygen therapy to manage severe respiratory distress. 

The sooner a patient is admitted to intensive care, the higher the chances of successful treatment.  If a patient is experiencing full distress, the effectiveness of treatment decreases.

How do People Become Infected with Hantavirus? 

In Nevada, deer mice are the reservoirs of the hantaviruses. The rodents shed the virus in their urine, droppings, and saliva. The virus is mainly transmitted to people when they breathe in air contaminated with the virus. When fresh rodent urine, droppings, or nesting materials are stirred up, tiny droplets containing the virus get into the air. This process is known as “airborne transmission“, which is the most common route of hantavirus transmission. 

There are several other ways rodents may spread hantavirus to people: 

• If a rodent with the virus bites someone, the virus may be spread to that person, but this type of transmission is rare. 

• Scientists believe that people may be able to get the virus if they touch something that has been contaminated with rodent urine, droppings, or saliva, and then touch their nose or mouth. 
• People can also become infected through direct contact with the bodily fluids or tissues of infected rodents, particularly if there are cuts or breaks in the skin. This can happen when handling live or dead rodents or when cleaning up rodent nests or droppings without proper protective gear. 
• Scientists also suspect people can become sick if they eat food contaminated by urine, droppings, or saliva from an infected rodent. 

The hantaviruses that cause human illness in the United States cannot be transmitted from one person to another. For example, you cannot get these viruses from touching or kissing a person who has HPS or from a health care worker who has treated someone with the disease. 

You might not notice a mouse or rat unless the infestation is severe. Watch out for signs of rat or mouse infestation:  

• Rodent droppings (black or dark brown pellets) found around food packages, inside drawers, under the sink or along baseboards. 
• Nesting materials like shredded paper, fabric, or dried plant matter. 
• Signs of chewing on food packaging. 
• Holes chewed through walls and floors, creating entry points into the home. 
• Musty odors coming from hidden areas. 
• Scratching, scurrying, or gnawing sounds, especially at night, can indicate activity in walls, ceilings, or under floors. 
• Pets, especially cats and dogs, may become excited or anxious around areas where rodents are active. 

Opening and Cleaning Previously Unused Buildings 

Opening or cleaning cabins, sheds, and outbuildings, including barns, garages and storage facilities, that have been closed during the winter is a potential risk for hantavirus infections, especially in rural settings. 

Housecleaning Activities 

Cleaning in and around your own home can put you at risk if rodents have made it their home too. Many homes can expect to shelter rodents, especially as the weather turns cold. Please see our prevention information on how to properly clean rodent-infested areas. 

Work-related Exposure 

Construction, utility and pest control workers can be exposed when they work in crawl spaces, under houses, or in vacant buildings that may have a rodent population. 

Campers and Hikers 

Campers and hikers can also be exposed when they use infested trail shelters or camp in other rodent habitats. The chance of being exposed to hantavirus is greatest when people work, play, or live in closed spaces where rodents are actively living. However, recent research results show that many people who have become ill with HPS were infected with the disease after continued contact with rodents and/or their droppings. In addition, many people who have contracted HPS reported that they had not seen rodents or their droppings before becoming ill. Therefore, if you live in an area where the carrier rodents, such as the deer mouse, are known to live, take sensible precautions-even if you do not see rodents or their droppings. 

• Stay away from rodents and avoid disturbing their nesting areas or burrows. 
• Maintain your outdoor gear (including tents, netting, sleeping bags, etc.) in good condition. Repair or replace any damaged items. 
• Avoid sleeping directly on bare ground. Use tents with floors or ground cloth.  
• Do not set up tents or place sleeping bags near rodent droppings. 
• Do not sleep in cabins that are currently infested with rodents or have recently been infested. 
• Store food in containers that rodents cannot access and avoid drinking surface water that has not been treated. 
• Follow site restrictions for handling trash and store it in rodent-proof containers until disposal. 

• Avoid Contact: Don’t touch live or dead rodents with your bare hands. Use gloves and take proper precautions to avoid direct contact with rodents or their fluids. 
• Rodent Control: Take steps to prevent rodent infestation in and around your home, such as sealing entry points and using traps and baits.  
• Proper Cleaning: When cleaning up areas with rodent droppings or nests, follow safe cleaning procedures. Spray the area with a disinfectant, avoid creating dust, and use masks, gloves, and protective clothing. 
• Ventilation: When entering enclosed spaces that may have rodent infestations, ventilate the area before cleaning or occupying it to reduce the concentration of potentially contaminated particles. 

What can I do to prevent rodent infestation in a home or building? 

To prevent rodents from entering a home or building, create an environment that doesn’t attract them:  

• Identify all potential rodent entry points. Seal holes both inside and outside the home to keep rodents out. For example, patching holes in interior or exterior walls. 
• Eliminate potential nesting sites in your home or building by removing leaf piles, deep mulch and keeping lawn mowed. 
• Eliminate food and water sources in and around your house: 
  • Keep your kitchen clean. 
  • Store kitchen garbage in containers with tight-fitting lids. 
  • Turn compost piles to cover newly added food scraps. 
  • Do not allow pet or animal food to sit out. 
  • Fix all leaky faucets that might provide water to rodents.

Prepare to clean up after rodents  

It is important to take proper precautions when cleaning to reduce your risk of getting sick. Before you start cleaning, prepare by gathering the proper equipment. 

• Prepare your disinfectant: 
• EPA-registered disinfecting products are recommended, confirm the word “Disinfectant” is included on the label. 
• Or bleach solution made with 1.5 cups of household bleach in 1 gallon of water (make bleach solution fresh before use). 
• Wear rubber or plastic gloves and a face mask. 

Clean up Rodent Urine and Droppings  

Step 1: Wear rubber or plastic gloves and a face mask. 

Step 2: Spray urine and droppings with bleach solution or an EPA-registered disinfectant until very wet. Let it soak for 5 minutes or according to instructions on the disinfectant label. 

Step 3: Use paper towels to wipe up the urine or droppings and cleaning product. 

Step 4: Dispose the paper towels in a covered garbage can that is regularly emptied. 

Step 5: Mop the area with a disinfectant. 

Step 6: Wash gloved hands with soap and water or a disinfectant before removing gloves. 

Step 7: Properly wash hands with soap and warm water after removing gloves and dry with disposable paper towels.  

How to Clean up a Dead Mouse  

Step 1: Wear rubber or plastic gloves and a face mask. 

Step 2: Spray the dead rodent, nest, and surrounding area with an EPA-registered disinfectant. Let it soak for 5 minutes or according to instructions on the disinfectant label. 

Step 3: Place the dead rodent or nesting materials in a plastic bag along with any used traps. 

Step 4: Tie the end of the plastic bag together in a knot to seal the bag. Place the full bag in a second plastic bag and seal that bag by tying the ends together in a knot. 

Step 5: Throw the bag into a covered garbage can that is regularly emptied or contact your local health department on other ways to properly dispose a dead rodent 

Steo 6: Wash gloved hands with soap and water or a disinfectant before removing gloves. 

Step 7: Properly wash hands with soap and warm water after removing gloves and dry with disposable paper towels. 

Cleaning and disinfecting different surfaces  

Porous and non-hard surfaces require different methods of cleaning and disinfecting. Follow these steps after rodent urine and dropping have been sanitized.  

• Clothing, bedding, and stuffed animals: Wash potentially contaminated bedding, clothing and stuffed animals with hot water and detergent. Machine dry on high setting or hang to air dry in the sun. 
• Carpets and upholstery: Shampoo rugs and upholstered furniture with a commercial disinfectant or with a commercial-grade steam cleaner or shampoo.  
• Books, papers, and other non-washable items: Leave books, papers, and items that cannot be cleaned with a liquid disinfectant outdoors in the sunlight for several hours, or in an indoor area free of rodents for a minimum of three weeks (a longer period of six weeks is strongly suggested) 

The deer mouse (Peromyscus maniculatus) is a deceptively cute animal, with big eyes and ears. Its head and body measure approximately 2–3 inches (5cm–7.5cm) in length, and the tail adds another 2–3 inches. In color, the deer mouse ranges from grey to reddish brown, depending on age. The underbelly is always white, and the tail has clearly defined white sides. The hantavirus strain present in deer mice is Sin Nombre Virus (SNV).  

8,664 Deer Mouse Images, Stock Photos & Vectors | Shutterstock 

Side View Deer Mouse On White Stock Photo 49595143 | Shutterstock 

Deer Mouse Habitat in North America 

The deer mouse is found throughout North America, preferring woodlands, but also appearing in desert areas. 

Reporting Hantavirus Cases in Nevada 

• Southern Nevada Health District (Clark County) 702-759-1300 (24 hours) 
• Northern Nevada Public Health (Washoe County) 775-328-2447 (24 hours) 
• Carson City Health & Human Services (Carson, Douglas, Lyon Counties) 775-887-2190 (24 hours) 
• Nevada Division of Public and Behavioral Health (All other Counties) 775-684-5911 (Monday – Friday 8am to 5pm) and 775-400-0333 (after hours) 

References 

Hantavirus (CDC) 

Identify and Prevent Rodent Infestations (EPA) 

Disease precautions for outdoor enthusiasts and their companion animals (AVMA) 

Preventing Hantavirus (CDC) 

How to Seal Up to Prevent Rodents (CDC) 

How to Clean Up After Rodents (CDC)