hantavirus

hantavirus, (genus Hantavirus), any member of a genus of viruses (Hantavirus) of the family Bunyaviridae that cause acute respiratory illnesses in humans. The hantaviruses are rodent-borne viruses, each of which has been evolutionarily adapted to a specific rodent host. Human infection occurs where people come into unusual and intense contact with infected rodent populations, mainly through inhaling dust containing dried rodent excreta in and around the home but also in the wild.

There are a number of different hantaviruses, each with specific rodent carriers, and they cause two basic groups of disease. The first group is known as hemorrhagic fever with renal syndrome (HFRS). These illnesses typically develop within 1 to 2 weeks of exposure (sometimes later) and are characterized by acute fever, severe headache, blurred vision, and nausea. Severe forms, such as those involving Dobrava virus or Hantaan virus, can result in internal bleeding and kidney failure. One of the first HFRS illnesses to be characterized was Korean hemorrhagic fever (also called hemorrhagic nephroso-nephritis), recognized during the Korean War (1950–53). Korean hemorrhagic fever is fatal in 5 to 15 percent of cases. It is caused by the Hantaan virus and is carried by the striped field mouse (Apodemus agrarius), a type of wood mouse that is prevalent in Asia and eastern Europe. A second HFRS disease, nephropathia epidemica, is usually not fatal. It is caused by the Puumala virus, which is carried by the bank vole (Myodes glareolus). Nephropathia epidemica has occurred in Scandinavia, western Russia, and other parts of Europe. Mild hemorrhagic illness can also result from infection with the Seoul virus, which is carried by the Norway rat (Rattus norvegicus). Seoul virus infections typically occur in Asia, though the virus has also been detected elsewhere, including in Brazil and in the United States.

The second group of hantavirus diseases is hantavirus pulmonary syndrome (HPS), which is recognized in a number of separate locations throughout the Western Hemisphere. HPS illnesses show a rapid onset of muscle ache and fever, leading to acute respiratory distress. These illnesses are fatal about 50 percent of the time. The first HPS illness was identified in the southwestern United States in 1993; it is associated with a virus called Sin Nombre, which is carried by the deer mouse (Peromyscus maniculatus). Other HPS illnesses have occurred in Florida, caused by the Black Creek Canal virus (carried by the hispid cotton rat, Sigmodon hispidus); Louisiana, caused by the Bayou virus (carried by the marsh rice rat, Oryzomys palustris); Chile and Argentina, caused by the Andes virus (carried by Oligoryzomys longicaudatus, a species of pygmy rice rat); and Central America, caused by the Choclo virus (carried by Oligoryzomys fulvescens, another pygmy rice rat).

Hantavirus infections are diagnosed by the symptoms, by a history of exposure to rodents, and by laboratory identification of antibodies to the virus circulating in the blood. Some cases have been treated with antiviral drugs such as ribavirin, but in most cases the focus is on controlling body temperature, fluids, and electrolytes. In severe cases the breathing is aided mechanically, and toxins are removed through kidney dialysis.

Hantavirus infections can be prevented by controlling rodent infestations around dwellings, by washing infested areas with solvents and disinfectants, and by limiting exposure to likely rodent environments in the wild.