Experimental toxoplasmosis in calves.

Nine calves were inoculated with tissue cysts of a low virulence strain of Toxoplasma gondii and killed at intervals up to 10 weeks. An immunological response took the form of circulating antibodies and reactive changes in the lymph nodes. The organism could only be recovered from the lymph nodes and this only during the first four weeks after infection. No tissue cysts were demonstrated and only a few inflammatory lesions occurred. Thus, although calves can be infected, the immunological response is prompt with rapid elimination of the organism.