Evidence of Human Infection with a Rat-Associated Hantavirus in Baltimore, Maryland

Viruses of the proposed genus Hantavirus in the family Bunyaviridae are etiologic agents of hemorrhagic fever with renal syndrome in Asia and Europe. Four antigenically distinct hantaviruses have been isolated from different rodent reservoirs, and three are associated with hemorrhagic fever with renal syndrome in humans. The primary virus-rodent associations and corresponding human diseases are Hantaan virus-Apodemus agrarius with Korean hemorrhagic fever and severe-type epidemic hemorrhagic fever in eastern Asia 1, 4 Puumala virus-Clethrionomys glareolus with nephropathia epidemica in eastern Europe, western Soviet Union, and Scandinavia 2 and Seoul virus and other isolates and species of Rattus with mild-type epidemic hemorrhagic fever in China and in laboratory outbreaks of hemorrhagic fever with renal syndrome 4-6 . Prospect Hill virus, isolated from Microtus pennsylvanicus in the United States, is known to infect humans, but is not associated with a disease 7. Recently, hantaviral infections in wild Rattus norvegicus of the United States were documented and shown by virologic and serologic techniques to be caused by a virus antigenically related to Seoul virus, isolated in 1980 from a Norway rat in Korea. We now report serologic evidence of human infections specifically due to a rat-associated Hantavirus in residents of Baltimore. To our knowledge, this is the first report to definitively link to a rat source the occurrence of hantaviral antibodies in humans who are lifelong residents of the United States.