Laboratory of Wildlife Ecology, Obihiro University of Agriculture and Veterinary Medicine, Hokkaido, Japan.
Green and Flower Center, Zoukei Inc., Hokkaido, Japan.
J Vet Med Sci. 2023 May 3;85(5):565-570. doi: 10.1292/jvms.22-0395. Epub 2023 Mar 29.
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.
泡状带绦虫引起人畜共患疾病，即泡型包虫病。泡状带绦虫的生命周期是通过红狐和啮齿动物之间的捕食者-被捕食关系维持的。红狐（Vulpes vulpes）感染泡状带绦虫被认为是啮齿动物摄入泡状带绦虫的虫卵，然后红狐捕食啮齿动物。然而，目前还不清楚啮齿动物是如何摄入虫卵的。在泡状带绦虫从红狐感染到啮齿动物的过程中，我们预测啮齿动物会通过觅食或接触红狐的粪便来利用粪便中未消化的物质。我们使用相机陷阱从 2020 年 5 月到 10 月监测了啮齿动物对狐粪的反应及其与粪便的距离。高山姬鼠和黑线姬鼠接触了狐粪，并且黑线姬鼠的接触率明显高于高山姬鼠。我们发现高山姬鼠对狐粪有嗅探和路过的接触行为，而黑线姬鼠则表现出直接接触粪便的行为。黑线姬鼠和高山姬鼠与狐粪的最短距离没有显著差异。两种啮齿动物的距离大多在 0 厘米到 5 厘米之间。高山姬鼠不觅食粪便且接触频率低，这表明红狐作为主要中间宿主向高山姬鼠传播感染的途径可能是其他途径。接近粪便和在粪便附近的行为可能会增加附着虫卵的概率。
