Abstract:To explore the pathogenicity of VEG strain Toxoplasma gondii oocysts on China Kunming mice,T. gondii oocysts of < 1 and 102-108 were chosen to feed the mice orally. And the modified agglutination test (MAT),H&E and IHC were used to check the infection of mice. The infection rate,the survival rate of mice,and number of cysts in brain were analyzed. Results showed that 100% of the mice fed with ≥102 oocysts were infected,the minimum lethal dose was 102 oocysts and the 100% lethal dose was 108 oocysts. The time of death in acute infection was 7 DPI to 14 DPI. T. gondii cysts formation rate was 32.14% (9/28),and the number of cysts was 9 to 857 per mouse. The survival rate of infected mice was 67.44% (29/43),and the longest survival time was more than 390 DPI. Accordingly,the virulence of T. gondii VEG strain is medium,and has a higher cysts formation rate.
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