86 



THE TRICHOMONADS 



and leopard frog agglutinated T. foetus at 

 1:2, those of the gold fish, pigeon and 

 domestic rabbit at 1:4, those of the guinea 

 fowl and chicken at 1:8, those of the turkey 

 and sheep at 1:16, those of deer and goat 

 at 1:32, that of the cow at 1:128 and that 

 of the horse at 1:1024. 



Nakabayasi (1952) distinguished be- 

 tween agglutination and agglomeration. 

 With immune rabbit and infected guinea 

 pig sera, agglomeration reached its max- 

 imum within 30 minutes and then decreased 

 gradually as the agglomerated individuals 

 separated. On the other hand, the agglu- 

 tination reaction reached its maximum 

 within about an hour and did not reverse. 

 Levine et al. (unpublished) have seen ag- 

 glomeration of T. foetus following mixture 

 with fresh culture media containing inac- 

 tivated serum. 



Kerr and Robertson (1954, 1956) 

 found "normal agglutinin" in the blood of 

 calves which they apparently acquired in 

 the colostrum; this agglutinin disappeared 

 after 17 to 55 days. Injection of calves 

 less than 4 weeks old did not induce anti- 

 body formation, but instead caused im- 

 pairment of antibody production (immuno- 

 logical paralysis) which persisted for 

 about 2 years. 



Complement fixation and precipitin 

 reactions have been studied, but with un- 

 satisfactory results (Svec, 1944; Morgan, 

 1948). 



Kerr (1944) developed an intradermal 

 test, using a trichloracetic acid-precip- 

 itated extract of T. foetus called "tricin. " 

 Positive reactions appear in 10 minutes, 

 reach their peak within 30 minutes and 

 disappear in about 6 hours. Fifty of 592 

 cows at an abattoir were positive to this 

 test, and trichomonads were found in 11 

 of them on direct examination. Tricho- 

 monads were also found in 11 of 34 bulls 

 which were positive to the skin test. 

 Morgan (1948) obtained negative results 

 with skin tests with a number of different 

 antigens. Kerr, McGirr and Robertson 

 (1949) found that cattle could be desensi- 

 tized to the skin test by injecting antigen 

 intramuscularly, instilling it into the 



uterus of non-pregnant cows, or by inject- 

 ing adreno-cortical hormone or sphingo- 

 myelin at parturition. Absorption of 

 antigen from acute uterine infections also 

 desensitized the animals. 



A local immune reaction takes place 

 in the vaginal mucosa of infected animals. 

 In addition, the uterine mucosa is sensi- 

 tized (Kerr and Robertson, 1953). The 

 presence of agglutinins in the vaginal 

 mucus prompted the development of a 

 mucus agglutination diagnostic test by 

 Pierce (1947a, 1949) and Florent (1947, 

 1948, 1957). This test is considerably 

 better than the blood agglutination test, 

 but, according to Pierce (1949), must still 

 be regarded as only a herd test because a 

 number of infected animals fail to react. 

 Unsatisfactory results are obtained with 

 estral and post-estral vaginal mucus and 

 with purulent uterine mucus containing 

 trichomonads. Mucus from pregnant an- 

 imals sometimes gives a false positive 

 reaction. Schneider (1952), too, consid- 

 ered the mucus agglutination test simply 

 an adjunct to other means of diagnosis. 



Morgan (1947a) found that a series of 

 16 intramuscular or intravenous injec- 

 tions with living T. foetus over a period of 

 3 months apparently protected heifers 

 temporarily against genital infection, but 

 6 intramuscular injections over a period 

 of 3 weeks did not. This does not appear 

 to be a practical method of prevention. 



Epidemiology : Bovine trichomonosis 

 is a venereal disease transmitted at coitus. 

 T. foetus is known to occur in cattle, but 

 whether it is also present in other animals 

 and whether it may be transmitted from 

 them to cattle by a non-venereal route re- 

 main to be determined. 



With the introduction of the technic of 

 preserving bovine semen by freezing in 

 the presence of glycerol, the question arose 

 whether T. foetus would survive in frozen 

 semen. Several investigators have studied 

 the problem, and have found that the pro- 

 tozoa may or may not survive freezing in 

 the presence of glycerol, depending on the 

 conditions (see Levine, Mizell and Houla- 

 han, 1958 for a review of the literature). 



