Recent reports of hantavirus cases in the media have raised public concern and renewed attention on the role that rodents have in disease transmission. This article explains what hantavirus is, how rodents are involved, and practical steps the public can take to reduce potential exposures.
What is Hantavirus?
Hantaviruses are a group of RNA viruses in the family Hantaviridae that are primarily carried by rodents and can cause disease in humans. In 2026, a hantavirus outbreak reported among cruise ship passengers was linked to Andes virus, a South American strain of hantavirus. While rodents are the primary reservoirs of hantaviruses, Andes virus is unusual because person-to-person transmission has been documented, although it appears to occur infrequently and is typically associated with close or prolonged contact. Common side-effects of Andes virus are flu-like symptoms, including chills, dizziness, fatigue, fever, headache, and muscle aches. If Hantavirus is left untreated, symptoms may progress into severe respiratory illness (Hantavirus Pulmonary Syndrome), and potentially death. As of June 2, 2026, the CDC considers the risk of Andes virus to the American public to be extremely low.
How Are Rodents Involved?
Each type of hantavirus is known to have a rodent carrier. In the case of Andes virus, the long-tailed pygmy rice rat (Oligoryzomys longicaudatus) is the primary reservoir host but is only found in southern South America. In Louisiana, marsh rice rats (Oryzomys palustris) and hispid cotton rats (Sigmodon hispidus) are among the rodent species associated with hantaviruses. In western and northern regions of the United States, deer mice are the primary reservoirs of hantaviruses, while white-footed mice serve as reservoirs for some hantaviruses in parts of the central and eastern United States. More commonly encountered rodents in the Southern US, such as the house mouse, roof/black rats, and Norway/brown rats, are not known to carry any hantaviruses. Hantaviruses are primarily spread by exposure to rodent urine, droppings, and/or saliva, but in some rare cases may be transmitted through physical contact via a bite or scratch.
Description: Small, robust body with coarse fur mottled black, brown, gray, and tan, a tail shorter than its body length, and relatively large ears and eyes.
Habitat: Prefers wetlands and other moist habitats, often found near marshes, swamps, ponds, and streams.
Description: Small, slender body with coarse grayish-brown fur mixed with black, relatively large eyes and ears, and a long, slender, sparsely haired tail.
Habitat: Prefers grassy habitats with dense ground cover, including fields, pastures, roadsides, and agricultural areas.
How Can I Reduce My Risk?
As marsh rice rats and hispid cotton rats are primarily sylvatic species, human exposure risk is generally associated with contact near natural or peri-urban habitats where these rodents occur. People at greatest risk include agricultural workers and individuals spending significant time in rural or outdoor environments. Avoid direct interaction with wild rodents if possible; if rodent handling is unavoidable, wear thick work gloves, long sleeves and pants, and a properly fitted N95 respirator or higher-rated mask to reduce direct contact and inhalation exposure.
When cleaning rodent feces or urine, avoid actions that may make aerial dust, such as sweeping or vacuuming. In enclosed areas, open doors and windows for at least 30 minutes before cleaning to ventilate the space. While wearing either rubber or plastic gloves, thoroughly spray drop or contaminated surfaces with a 1:10 household bleach solution or EPA-registered disinfectant until wet. Allow the disinfectant to soak for at least 5 minutes before wiping clean with paper towels. Dispose of used paper towels in a covered garbage container and wash hands thoroughly with soap and warm water afterward.
Homeowners in rural areas may also consider preventative rodent-proofing measures. Keeping grass and vegetation trimmed can help reduce outdoor harborage areas, while removing food sources such as outdoor pet food and bird feeders may reduce rodent activity. Sealing gaps around doors, pipes, cables, vents, and foundations can help prevent rodents from entering structures. Mice can fit through openings as small as 1/4 inch (~6 mm), while rats can enter through gaps as small as 1/2 inch (~12 mm). In addition to exclusion, rodent populations can be managed through trapping and, when appropriate, the use of rodenticides as part of an integrated pest management (IPM) program.
Contributing Authors
Chance Hudnall, Graduate Research Assistant
Aaron Ashbrook, Assistant Professor of Urban/Peri-urban Entomology
Department of Entomology
Louisiana State University
