[Kinetic study of the multiplication of the mucosal disease--viral diarrhea virus in homologous cell cultures].

Comparative studies were carried out on two local cytopathic strains of the virus of mucous disease-viral diarrhoea in primary cell cultures of fetal calf kidney and cell cultures of normal calf kidney in order to ascertain the yield of the virus and the development of a cytopathic effect. It was found that the amount of virus of the strain with strongly manifested cytopathic effect was directly proportional to its activity in the cell cultures of fetal calf kidney. Highest titers of the virus were obtained at the time of full cytopathic effect. In the same cultures the yield of the virus strain with less strongly manifested cytopathic effect was highest prior to the time of its fullest. The kinetics of propagation of the two viruses when culturing in such media proved to be similar to that when normal calf kidney cultures were used, however, the titers of the virus were lower by 1-2 logarithms. Both freezing and thawing of viral suspensions were found to contribute to the release of the virus from the incompletely destroyed cells. The yield of the virus in such cases rose only with the strain with a weak cytopathic effect if the procedure was carried out prior to its full manifestation.