The Detection of the Mycobacterium Avium Subspecies Paratuberculosis in Environmental Samples as a Screening Test to Determine A Herd's Paratuberculosis Status

摘要

Paratuberculosis (PTB), caused by Mycobacterium avium subspecies paratuberculosis (MAP), is chronic enteritis that provokes infertility and a decrease in milk production. The amount of MAP in the feces (shedding level：SL) of MAP-shedding cattle progressively increases, and that of cattle with clinical symptoms is108 CFU/g. Cattle reared in an environment heavily contaminated with MaP by high-shedders are easily infected. Since, the prevention of MAP transmission requires the culling of low-sheddersthat have not yet become high-shedders. As the national PTB eradication surveillance in Japan, all targeted cattle are tested and culled at intervals of less than 5 years. To accelerate eradication, the test interval must be shortened because most casesoccur between 3-5 years of age. However, more frequent testing of individual cattle is hampered by a shortage of labor. It has been reported that the detection of MAP in environmental samples by quantitative PCR (ENV-qPCR) is effortless. This study evaluated the efficacy of ENV-qPCR as a screening test to determine a herd's PTB status.