Species and strain differences in sensitivity to Toxoplasma infection among laboratory rodents.

Different susceptibilities to Toxoplasma infection were shown among various inbred and outbred laboratory rodents. On the basis of several criteria, the animals can be divided into three groups: (i) highly sensitive (S) mice, Syrian hamsters and Chinese hamsters; (ii) moderately sensitive (M) Mongolian gerbils and mastomyses ; and (iii) resistant (R) rats and Korean striped field mice. S and M hosts supported intraperitoneal growth of the parasites and died of acute infection. M hosts showed prolonged time to death and low fatality as compared with S hosts. Some R hosts died only when they had received an extremely large size of inoculum, accompanying poor intraperitoneal proliferation of the parasite. WM/Ms and WKY rats markedly resisted the infection. These hosts were considered to be useful models for studying infection of and immunity to toxoplasmosis.