Dubey J P, Streitel R H
J Am Vet Med Assoc. 1976 Dec 1;169(11):1197-9.
Specimens of heart, diaphragm and, in 159 instances, esophagus were taken from 352 cattle slaughtered in an Ohio abattoir. The total weight of the material was 32 kg, and this was fed to 12 specific-pathogen-free cats to test for Toxoplasma infectivity. None of the 12 cats acquired Toxoplasma infection, as evidenced by their failure to excrete oocysts or to develop antibodies, and by failure to isolate Toxoplasma from their tissues by inoculation into mice. In further tests, a 650-g sample of beef from 77 of the 352 cattle was digested in 1% trypsin, then inoculated intraperitoneally into 40 mice. Toxoplasma was not isolated from the mice. Serums from 186 of the 352 cattle were inactivated at 60 C for 1 hour, then examined by the Sabin-Feldman (dye) test for antibodies to Toxoplasma. None had titers of more than 1:8. Of the 186 serums, 77 were also examined for antibodies in the indirect hemagglutination test. One had a titer of 1:64, which was considered nonspecific. Thus, evidence for Toxoplasma infection was not found in 352 cattle.
从俄亥俄州一家屠宰场宰杀的352头牛身上采集了心脏、横膈膜样本，其中159例还采集了食管样本。这些样本总重32千克，将其喂给12只无特定病原体的猫，以检测弓形虫感染性。12只猫均未感染弓形虫，这可从它们未排出卵囊、未产生抗体以及通过接种小鼠未能从其组织中分离出弓形虫得到证明。在进一步的试验中，从352头牛中的77头牛身上取了650克牛肉样本，用1%的胰蛋白酶消化，然后腹腔接种到40只小鼠体内。未从小鼠身上分离出弓形虫。将352头牛中186头牛的血清在60℃灭活1小时，然后用Sabin-Feldman（染料）试验检测抗弓形虫抗体。无一例滴度超过1:8。在这186份血清中，77份还用间接血凝试验检测了抗体。其中一份滴度为1:64，被认为是非特异性的。因此，在352头牛中未发现弓形虫感染的证据。
