Resistance of Berne virus to physical and chemical treatment

Thermal inactivation of Berne virus proceeded at a linear rate between 31°C and 43°C. Storage at temperatures lower than −20°C preserved the infectivity, while at 4°C appreciable loss occurred between 92 and 185 days. Freeze-drying or desiccation at 22°C caused only insignificant loss of infectivity. Virus preparations were not affected by pH values between 2.5 and 10.3. Inactivation by UV occurred more rapidly than with herpes, toga and rhabdoviruses. Berne virus infectivity was sensitive to pronase and B. subtilis proteinase. It was not inactivated by trypsin and chymotrypsin treatment, which resulted in enhancement of infectivity; low concentrations of pronase (< 10 μg ml(−1)) had a similar effect on Berne virus. Neither phospholipase C or RNase, alone or in combination, nor sodium deoxycholate (0.1%) inactivated the virus; in contrast, Triton X-100 (0.1%, 1.0%) caused rapid inactivation with a constant level of residual infectivity.