Hantaan virus, aetiological agent of Korean haemorrhagic fever, has Bunyaviridae-like morphology.

Spherical to oval particles with a unit membrane and subunit surface structure were demonstrated by negative-contrast staining of supernatant fluids of A-549 cell cultures infected with strain 76-118 of Hantaan virus. The particles had an average diameter of about 95 nm, with a range of 80 to 110 nm. Similar particles were isolated by buoyant density fractionation in sucrose gradients. In four separate experiments, infectivity cosedimented with 95 nm particles at buoyant densities from 1.15 to 1.18 g/ml. Immunoaggregation of the virions was specifically produced by antisera obtained after Hantaan virus infection of man and rabbit. The known physicochemical and morphological properties of these particles are compatible with those generally reported for the Bunyaviridae family of viruses.