Response of wild rodents to red fox feces: implication for the echinococcus infection.

Echinococcus multilocularis causes zoonotic disease, alveolar echinococcosis. The life cycle of E. multilocularis is maintained by the predator-prey relationship between red foxes and rodents. Infection to red fox (Vulpes vulpes) of E. multilocularis is considered that rodents take eggs of E. multilocularis, then red fox forage the rodents. However, it has been not known how to take eggs by rodents. On infection process of E. multilocularis from red foxes to rodents, we predicted that rodents would forage or touch with feces of red fox to use undigested materials within the feces. We monitored rodent's response to fox feces and their distance to the feces by using camera trap from May to October 2020. Myodes spp. and Apodemus spp. touched fox feces, and touch rate of Apodemus spp. was significantly higher than that of Myodes spp. We found smelling and passing as contact behaviors to fox feces by Myodes spp., while Apodemus spp. showed behaviors which oral directly contacted feces. There was no significant difference on the shortest distance between Apodemus spp. and Myodes spp. The distance between 0 cm and 5 cm was mostly observed for both rodents. The results that Myodes spp. did not forage feces and their contact to feces was low frequency suggested that the infection from red foxes to Myodes spp., the main intermediate host, was to be other pathways. The approach to feces and the act near feces might increase the probability attached with eggs.