Cats--source of protection or infection? A case-control study of hemorrhagic fever with renal syndrome.

In the first case-control study analyzing risk factors in sporadic hemorrhagic fever with renal syndrome, 111 cases occurring in Shanghai in 1983 and 1984 and 136 matched controls were studied. Three factors were associated with risk of disease: travel in the month before onset of illness, intense exposure to rodents in the home, and cat ownership. Risk associated with cat ownership was not confounded by exposure to rodents in the home. Neither cat ownership nor risk associated with rodent exposure was confounded by history of travel. The role of cats as reservoir hosts of Hantaan virus is undefined, but this epidemiologic study indicates that infected cats may pose an important risk in the spread of this virus to humans. A survey of peridomestic animals in suburban Shanghai disclosed Hantaan virus infections in two rodent species and in an insectivore, Suncus murinus.