Hantaviruses are a group of viruses carried by specific types of wild rodents across the globe. In the Americas, these viruses cause a rare but severe illness in humans known as Hantavirus Pulmonary Syndrome (HPS). HPS is characterized by a rapid onset of respiratory distress and has a fatality rate sometimes reaching 38% of reported cases. The virus does not cause noticeable illness in its rodent hosts, which shed the pathogen through their urine, feces, and saliva.
Is Hantavirus Contagious Between Humans?
The hantavirus strains found in North and Central America, including the predominant Sin Nombre virus, are not spread from one person to another. Since the virus requires a specific rodent host to complete its lifecycle, a human infection is considered a dead-end for the pathogen. You cannot acquire HPS by touching or being near a person who is sick with the virus, and healthcare workers cannot contract it from a patient.
An exception exists with the Andes virus, which is found only in South America, primarily Argentina and Chile. This is the single known strain that has demonstrated human-to-human transmission. Spread typically occurs after prolonged and close contact with an infected individual, such as within a household or hospital setting. This unique transmission route is not a concern for the majority of the global population, as the Andes virus is geographically restricted.
Primary Routes of Human Infection
Since direct human-to-human spread is not a concern for the HPS-causing strains in North America, the mechanism of infection centers on the rodent reservoir. Humans contract the virus primarily by inhaling tiny airborne particles contaminated with viral matter. The virus is shed in the excretions of infected rodents, such as the deer mouse, white-footed mouse, cotton rat, and rice rat.
When these infected excretions dry, any disturbance can aerosolize the particles, creating a fine mist that is breathed into the lungs. Exposure often occurs in enclosed spaces that have been vacant for long periods, such as cabins, sheds, barns, or crawlspaces. Activities like cleaning a dusty storage area or disturbing a rodent nest can stir up the contaminated dust and lead to infection. The virus can also enter the body if contaminated material touches broken skin, or if a person touches their nose or mouth after handling droppings.
The deer mouse (Peromyscus maniculatus) is the most common carrier of the Sin Nombre virus, which causes the majority of HPS cases in the United States. These rodents continuously excrete the virus, making any area they inhabit a potential source of infection. Exposure risk is highest in rural and semi-rural areas where these specific rodent populations thrive.
Recognizing the Signs of Infection
Hantavirus Pulmonary Syndrome progresses through two distinct phases, with symptoms appearing one to eight weeks after exposure. The initial phase often mimics a severe case of the flu, making early diagnosis difficult without a history of rodent exposure. Patients commonly experience the abrupt onset of fever, chills, and muscle aches, particularly in the thighs, hips, and back.
Other early signs include headaches, dizziness, and gastrointestinal issues like nausea, vomiting, or abdominal pain. This initial stage lasts for several days before the disease rapidly progresses to the respiratory phase. Within four to ten days of the initial symptoms, the condition worsens significantly, moving from a flu-like illness to respiratory failure.
The later symptoms are characterized by a sudden cough and rapidly increasing shortness of breath. This difficulty breathing is caused by fluid leaking from blood vessels into the lungs, a condition called pulmonary edema. Low blood pressure and a rapid heart rate are also common as the body struggles to maintain oxygen levels. Seek immediate medical attention if flu-like symptoms develop following any potential exposure to rodents or their waste.
Reducing Your Risk of Exposure
Controlling the rodent population and safely cleaning contaminated areas are the most effective ways to prevent HPS infection. Before attempting to clean any potentially infested space, open all doors and windows to ventilate the area for a minimum of 30 minutes. This airing-out period helps to disperse any aerosolized viral particles that may be present.
Avoid cleaning methods that stir up dust, such as sweeping, dry dusting, or vacuuming. Instead, wet the contaminated areas, including droppings and nests, with a disinfectant solution before removal. A common solution is a mixture of one part household bleach to ten parts water.
Allow the bleach solution to soak for at least five to ten minutes to deactivate the virus before wiping the materials away with a paper towel. Always wear rubber, vinyl, or nitrile gloves during cleanup and wash them thoroughly before removal, followed by washing your hands. Sealing up holes and gaps in homes, sheds, and garages is a long-term strategy to prevent rodents from entering and establishing new habitats.