[Occurrence of Toxoplasma gondii antibodies in blood donors 1980-1990].

In 1980-1990 in the Strakonice district parallel serological examinations, using the Sabin-Feldman test (SFT) and complement fixation test (CFT), were made in 2,758 blood donors for the presence of antibodies against toxoplasmosis. The total number of examinations was 8,245. In the course of the mentioned time interval no significant increase or decrease of the serological prevalence occurred. During the first examination of blood donors the SFR antibodies (titre > or = 4) were detected in 45.4%, CFT (titre > or = 10) in 24.6% donors. 651 blood donors were examined four times or more frequently after 6-month intervals. 22.9% donors lacked antibodies (SFT and CFT) permanently, a rarely present low titre was recorded in another 22.9% donors, a repeated low titre in 43.6% and a repeatedly encountered medium or high titre in 10.6% of blood donors.