Influence of tick-borne encephalitis and West Nile viruses on the chromosomes of pig kidney cells.

Changes of the mitotic index (MI) were studied in pig kidney (PS) cells infected either with tick-borne encephalitis (TBE) virus strains Hypr and Ir-32, or with West Nile (WN) virus prototype strain, strains K-99 and E-13. The cell division was arrested by the infection (metaphase barrier). The effect of TBE virus strains was manifested by the appearance of lagging chromosomes while the action of WN virus strains by colchicine--like metaphases.

[Differences in strains of tick-borne encephalitis virus with respect to the sensitivity of their hemagglutinins to the action of detergents].

Tick-borne encephalitis virus strains (TBE) differ in sensitivity of their hemagglutinating properties (HA) to the detergents: giamine 10-x triton X-100, bridge-58, sodium deoxycholate. These characteristics of different sensitivity to detergents were stable in virus passages in mice and apparently may be used as markers in comparative studies of different strains.

Comparative studies on sindbis virus strains isolated in Slovakia.

Two variants of Sindbis virus strains were distinguished according to the dextran sulphate (DS) marker. Large-plague strains freshly isolated from Cricetus cricetus and Rana ridibunda produced exclusively small plaques after DS treatment. The prototype Sindbis virus strain produced both large and small plaques after DS treatment.