Badania nad zjadliwością toksoplazm przechowywanych in vitro

Studies were conducted on virulence and survival of toxoplasms of the strain RH stored in vitro at temp. 4°C. taking into consideration the following suspending media: physiological solution Of NaCl, bovine serum and buffered Hanks' fluid with addition of 10 per cent bovine serum. The titre LD50 was determined according to Reed and Muench for parasites suspended in the separate fluids. Subsequent determinations were made at 1, 3, 5, 10, 12 and 14 days intervals. For every dilution were used 6 mice, observation period was 14 days. Vitality and virulence of toxoplasms stored in physiological solution NaCl were found still after 12 days. The titre LD50 dropped during that period from 10-6,24 to 10-0,58. Parasites stored in this medium for 14 days did not infect any of the mice. It was found that bovine serum exerts an advatageous influence on the survival of Toxoplasma gondii in vitro. Comparing the virulence of toxoplasms stored in physiological solution NaCl and bovine serum using for the determination of statystical significance of differences of variation of Olechnowitz and Pizzi - diffevences for the majority of cases were found statystically significant.