[Study of closed colony of Microtus fortis infected with Schistosoma japonicum].

Objective: To understand the pathological changes of tissues and organs in Microtus fortis infected with Schistosoma japonicum for further insight into the biological dynamic variation and explore immune mechanisms of M. fortis against S. japonicum infection.
Methods: The healthy M. fortis and mouse were infected with cercariae of S. japonicum through abdominal skin. On the day 12, 20 and 40, the M. fortis and mouse were sacrificed by cervical dislocation and dissected. The liver and kidney slices of M. fortis and mouse of the different groups were prepared and stained with hematoxylin eosin stain (HE) by conventional techniques, respectively.
Results: We did not find obvious lesions on the internal organs of mouse 12 d and 20 d after the infection and the lesions of M. fortis 40 d after the infection. However, white nodules appeared on the liver, kidney and spleen of the M. fortis 12 d and 20 d after the infection, and there were a lot of S. japonicum worms on pathological sections of inflamed liver and kidney tissues, and the boundary between worms and normal organization was clear. There were no parasites on pathological section of liver and kidney of mouse 12 d and 20 d after the infection.
Conclusion: Among M. fortis, there are severe immune responses and the immune responses have an individual difference 12 days after S. japonicum infection.