Virulence of VEG strain Toxoplasma gondii oocysts against Kunming mice / 中国人兽共患病学报

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.