The Primary Carriers
Specific rodent species are primary carriers of Hantavirus, particularly in North America. The deer mouse (Peromyscus maniculatus) is the most significant reservoir for Sin Nombre Hantavirus, which causes most Hantavirus Pulmonary Syndrome (HPS) cases in the United States. Other species, such as the white-footed mouse (Peromyscus leucopus), cotton rat (Sigmodon hispidus), and rice rat (Oryzomys palustris), can also carry different virus strains depending on their geographic range.
These rodents inhabit various environments across North America. Deer mice, for example, are found in rural fields, forests, and suburban areas, often seeking shelter in sheds, barns, and homes, especially during colder months.
How Hantavirus Spreads
Hantavirus primarily spreads to humans through contact with infected rodent urine, droppings, or saliva. When these materials dry, they can become aerosolized, meaning tiny virus particles become airborne. Humans can then inhale these particles, leading to infection.
Transmission can also occur if people touch their nose, eyes, or mouth after handling contaminated materials or surfaces. Other routes include direct contact with an infected rodent, such as through a bite, or consuming food contaminated by rodent excretions. Human-to-human transmission of Hantavirus is not known to occur in the United States.
Understanding the Symptoms
Symptoms of Hantavirus Pulmonary Syndrome (HPS) typically appear one to five weeks after exposure, though the incubation period can range from a few days to eight weeks. The initial phase often resembles a common viral illness, characterized by fatigue, fever, and muscle aches, particularly in the large muscle groups like the thighs, hips, and back. Headaches, dizziness, chills, and abdominal problems like nausea, vomiting, diarrhea, or abdominal pain can also occur.
As the disease progresses, usually four to ten days after initial symptoms, respiratory distress becomes pronounced. Patients may experience a dry cough and shortness of breath, which can rapidly worsen. Fluid fills the lungs, leading to severe breathing difficulties and a drop in blood pressure. Prompt medical attention is needed if these symptoms develop after potential rodent exposure.
Preventing Exposure
Preventing Hantavirus exposure involves reducing contact with rodents and their droppings, especially in enclosed spaces. Seal holes and gaps in homes and outbuildings to prevent rodents from entering, including openings in foundations, walls, and around pipes.
When cleaning areas that may be contaminated with rodent droppings, take specific precautions to avoid aerosolizing the virus. Ventilate the area by opening doors and windows for at least 30 minutes. Wear rubber or plastic gloves and a respirator with a HEPA filter (N95 or higher) to prevent inhaling airborne particles. Do not sweep or vacuum dry rodent droppings or urine, as this can release the virus into the air.
Instead, wet down contaminated areas with a bleach solution (one part bleach to nine parts water) or another household disinfectant before wiping them up with paper towels. Place all contaminated materials, including dead rodents, in a double plastic bag, seal it, and dispose of it in a covered trash can. After cleaning, disinfect gloves and wash hands thoroughly with soap and water.
To control rodent populations, set traps like snap traps. Regularly clear away potential rodent food sources, such as spilled bird seed or pet food, and store food in rodent-proof containers. Maintaining tidy outdoor spaces by keeping grass mowed and clearing brush away from foundations also reduces attractive habitats for rodents.