Hantaviruses are single-strand RNA viruses that are members of the Bunyaviridae family. Hantavirus produces two different syndromes depending on the strain: hantavirus pulmonary syndrome (HPS) and hemorrhagic fever with renal syndrome (HFRS). Both are zoonotic infections with rodents as their natural host. Natural infection is acquired by inhalation of an aerosol or dust containing rodent excreta and by rodent bites. With a mortality rate of 50%, HPS is a potential agent of bioterrorism. The most likely method of dispersal would be as an aerosol. HFRS has a mortality rate of only 5%; this could be higher following an aerosol bioterrorism attack due to a higher initial viral exposure. Any large outbreak of HPS in the United States should be suspect for a bioterrorism attack.

The incubation period for HPS ranges from 1-6 weeks but usually lasts for 2 weeks. Initial symptoms include the sudden onset of fever, dry cough, fatigue, dizziness, myalgia, headaches, chills, nausea, vomiting, and abdominal complaints. Arthralgias and back pain occur less frequently. The disease progresses rapidly to high fever, unremitting coughing, dyspnea, tachypnea, tachycardia, and rales, leading to diffuse pulmonary edema, ARDS, and, frequently, death. Rarely, some patients may develop DIC. By the time most victims seek medical care, they are usually so advanced in the illness that they require immediate respiratory support.

HPS was first identified in the southwestern United States in 1993. Since that time, more than 700 cases have been identified throughout the country. In 2012, several confirmed cases of HPS were associated with staying at cabins in Yosemite National Park in Yosemite Valley, California. There are 4 major hantavirus strains in North America: Sin Nombre (carried by the deer mouse; found throughout North America), Black Creek Canal (carried by the cotton rat; found in the southeastern United States and Central and South America), New York (carried by the white-footed mouse; found in southern New England, the mid-atlantic, southern, midwestern, and western United States, and Mexico), and Bayou (carried by the rice rat; found in the southeastern United States and Central America). The common house mouse and house pets do not carry hantaviruses. Person-to-person transmission has not been documented except for Andes hantavirus (ANDV) (endemic in Chile and Argentina; the only hantavirus for which person-to-person transmission has been reported).

At present, no vaccine is available.

Some farm and domestic workers, building and fire inspectors, hikers, campers, laboratory workers, mammalogists, pest-control workers, and people who enter or clean rodent-infested structures are susceptible to contracting HPS.

HPS should be reported to the local health department.

Note: Use HEPA or N-95 filter mask and gloves when handling rodents or traps or when cleaning large deposits of rodent excreta. Air out and disinfect rodent-infected areas with a solution of 1 part bleach in 9 parts water.