A standard method for evaluation disinfectant activity deve loped by the German Veterinary Sociaty (1974), which is also fully described, was used in this investigation. The antiviral activity of 2% formalin, 2% lysovetR J-forte and 2% sodium hypochlorite against NDV was studied in suspension and organism carrier ex periments. Results obtained are summerised in the following: 1. In suspension experiments, formalin and lysovet R J-forte
in 2% concentration inactivated NDV within 15 min. ex posure even in the presence of cattle serum (protecting
substance). 2. 2% sodium hypochlorite failed to show any disinfecting
activity on NDV in the presence of the protecting substace. In carrier surfaces disinfection experiments with formalin, NDV gauze-carrier surface was inactivated in 15 min., whereas on egg shell carrier needed 30 min exposure, Wood carrier proved to be difficult to disinfect even after 60min.
exposure. 4. It could be concluded that disinfecting activity depends
on the virus to be disinfected, disinfectant chosen, kind of
carrier surface, exposure time and temperature.