Electron microscopy, plaque assay and preliminary serological characterization of three ectromelia virus strains isolated in Poland in the period 1986-1988.

Three strains of viruses have been identified as ectromedia virus (EV) based on their origin, clinical features, morphology, size of virions (140 x 220 nm), replicative ability and specific cytoplasmatic fluorescence. The mean diameter of plaques produced by EV strains was 0.76 mm (range 0.5-1.0 mm). The neutralizing properties of the tested sera were evaluated by seroneutralization (SN) and hemagglutination inhibition (HAI) tests.