1960 Volume 13 Issue 12 Pages 538-543
Recently swine toxoplasmosis has become very common in Japan. This paper presents comparative studies between DT and CF test, including the authors' complement fixation inhibition (CFI) test, on swine and cattle experimentally infected with toxoplasma. It also presents the results of a serological survey carried out by the application of CFI test, by means of which it was successful to detect naturally infected animals in some pig farms.
The antigen was prepared in accordance with the method of Warren and Russ (1948). By adding the embryonal fluid to the CAM, such good results were obtained as to avoid the anti-complementary properties of antigens.
Immune guinea-pig serum (IGPS) was prepared as follows. Guineapigs were injected intraperitoneally ten times, at one week's intervals, with 1: 100 dilution of the peritoneal exudate of a guineapig which had previously been infected with toxoplasma. Convalescent blood was taken 3 weeks later. Immunization was improved under the protection from death with the aid of a therapeutic medicament.
Prior to the CFI test, appropriate amounts of IGPS and antigen to be used in the final test were determined by the direct CF method using boxtitration (table 2).
Final CFI test was performed as was shown in table 1. Inactivation temperature and time are very important. The authors inactivated the sera at 60°C for 20 minutes according to the results obtained from the experiments.
In the field screening test, the positive limit for this test is recommended by the authors as follows: over 1: 8 dilution of serum, positive; 1: 4 to 1: 2 dilution, suspected; and below 1: 2 dilution, negative.