Epidemiological situation and control strategies for paratuberculosis in Japan

Paratuberculosis (Ptb), caused by Mycobacterium avium subsp. paratuberculosis (Map), is a chronic and progressive granulomatous enteritis that affects many livestock and wild animals worldwide. The clinical disease is called Johne's disease (JD). In Japan, all dairy cattle (harf million head) are examined for Ptb every five years. About 1000 the officially examined cattle are diagnosed annually as positive for Ptb, but most of these exhibit only minor or no clinical signs and typical lesions in recent years. In contrast to the situation in Japan, the disease prevalence in western countries is very high. We have used ELISA and a culture examination of Map, and recently real-time PCR to diagnose this disease. In this review, the author outlines the history of the epidemic and national practical strategies to control paratuberculosis in Japan.