Abstract: Objective:To establish the suckling mouse model of extraintestinal rotavirus infection.Methods:Thirty-two ICR mouse aged from 10 to 11 days were randomly divided into two groups,with 16 in each.The extraintestinal infection group were inoculated by intraperitoneal injection of 150 μl simian rotavirus SAl1 (the virus titer of TCID₅₀ was about 10^-4) and the control group were inoculated by intraperitoneal injection of 150 μl normal saline.After inoculation,the mouse activities,diet,somatotype,change of hair color and stool were observed.All the suckling mouse were killed 4 days later,and the heart,liver,kidney,spleen and intestines were collected for pathological section and homogenate culture.Results:After two days of infection,the suckling mouse in extraintestinal infection group began to lose appetite,their clothing hair was tarnished and activities were decreased;They were dull,lethargy and slow to outside stimulus;meanwhile,their stool amount was reduced;the symptoms aggravated gradually and reached the peak at the fourth day;moreover,three mouse demonstrated the symptom of diarrhea.In the whole process of observation,the cumulative diarrhea rate and inception rate were 18.75% and 100.00%,respectively.Pathological changes were observed in the liver,kidney,spleen and intestines by light-microscope.After 72 hours of homogenate culture,cytopathic effect was observed in the liver,kidney and intestines,but no obvious changes were noticed in the heart or spleen.The suckling mouse in control group presented normal condition.Conclusions:It is feasible to establish the suckling mouse model of extraintestinal rotavirus infection with this method.