Infectivity and Pathogenicity of 'Toxoplasma' Oocysts for Swine.

摘要

The oocyst of Toxoplasma gondii, which is formed in the epithelium of the cat intestine and excreted in the feces, appears to be the primary infective particle of the parasite. Studies have shown the oocyst to be infective for a wide variety of mammals, birds, and possibly man (Miller et al., 1972, J. Parasit. 58: 928-937). The role of the oocyst in acute toxoplasmosis is relatively unstudied; however, one study (Draper et al., 1971, Brit. Med. J. 2: 375-378), using chimpanzees, demonstrated that oral inoculation of massive numbers of oocysts (2.5 x 10 to the 3rd power) produced only a transient lymphadenitis and few other symptoms in one chimp. The purpose of this study was to determine the number of oocysts required to infect and/or cause clinical toxoplasmosis in susceptible pigs.