Continuous Moniezia benedeni Infection in Confined Cattle Possibly Maintained by an Intermediate Host on the Farm

Infection with Moniezia benedeni is sometimes found in confined cattle in Japan. Between October 2011 and January 2013, we monitored the fecal egg prevalence at a confined cattle farm in Miyazaki prefecture where continuous M. benedeni infection has been recognized for years to evaluate the possible infection routes. Fecal egg prevalence changed seasonally with the highest in October 2011 (27.3%: 9/33). This was followed by a gradual decrease until July 2012 (9.4%: 3/32) and then an increase between August to December 2012 when new egg-excreting cases were observed. The pattern of seasonal changes was similar to that reported previously for cattle kept in a barn with an outside playing yard. Although M. benedeni-infected mites were not found, we constantly detected an oribatid mite, Oribatula sakamorii Aoki, 1970, in the litter of cattle bedding from May to October 2012. This species belongs to a genus which has been reported to be a suitable intermediate host for M. benedeni, suggesting that M. benedeni infection may have been autonomously maintained at the farm via oribatid mites living in the cowshed. When infected cattle were treated with praziquantel, it was found that a single oral inoculation with a dose of 5 mg/kg was effective for deworming.