Hantaviruses

HANTAVIRUSES

Hantavirus Hemorrhagic Fever

Korean hemorrhagic fever (KHF) is endemic to Korea and surrounding areas in the Far East. It is an important cause of hemorrhagic fever, often complicated by varying degrees of acute renal failure. In the 1950s, thousands of military personnel developed the disease during the Korean War. The first reported isolation of KHF was in 1978, when the antigen was detected in the lung tissues of wild rodents (Apodemus species) by indirect immuno-fluorescence using convalescent sera from affected patients. No illness was apparent in the rodents, suggesting a reservoir mechanism and mode of transmission similar to those described for the arenaviruses. Additional work indicated that the agent is a member of the family Bunyaviridae, and the generic designation of Hantavirus was given.

Evidence has accumulated indicating that other agents with close antigenic similari-ties to KHF virus are responsible for hemorrhagic–renal syndromes occurring throughout northern Eurasia, including Russia, Eastern Europe, Finland, and Scandinavia. These syn-dromes have been given a variety of names, including nephropathia epidemica. Methods similar to those used to detect KHF have detected nephropathia epidemica antigen in the lungs of small rodents (bank voles) in Finland.

Other Hantavirus Infections

It has been known for some time that rodents in the United States may be infected with a hantavirus, but no associated human disease was recognized. In early 1993, an outbreak of fulminant respiratory disease with high mortality (50 to 75%) occurred in the south-western United States. This syndrome (hantavirus pulmonary syndrome, or HPS) has been related to at least three hantaviruses, of which Sin Nombre virus is the most common. Infections are associated with an increased population of infected mice in and around hu-man habitations. Of the more than 30 documented HPS illnesses reported in 1993, 23 pa-tients resided in rural areas of a region bordered by the states of Arizona, New Mexico, and Colorado; however, cases have also been reported from at least 19 other states. The virus is believed to be transmitted to humans most often by inhalation of infected rodent excreta, by the conjunctival route, or by direct contact with skin breaks. Human-to-human spread has not been encountered. Public health measures to inform inhabitants of routes of spread and to reduce the rodent population appear to have controlled the outbreak.

Treatment has involved aggressive respiratory support. Intravenous ribavirin appears to have been of benefit in Asian hantavirus infections; however, there are no data as yet re-garding its efficacy against the US strains.