First characterization of Mycobacterium avium subsp. paratuberculosis strain types in cattle from Kushiro Subprefecture, eastern Hokkaido, Japan

Abstract

Johnes disease (JD), caused by Mycobacterium avium subsp. paratuberculosis (MAP), is an important livestock disease in Japan. We typed 48 field isolates from cattle feces collected on 13 farms in Kushiro Subprefecture during 2024-2025 and 62 MAP-positive cattle fecal samples collected in the same region during 2025-2026 using a real-time PCR assay targeting the Type S-specific arylsulfatase gene. No Type S strains were detected among the cultured isolates or fecal samples examined in this study, suggesting that the cattle cases analyzed were more consistent with Type C than with Type S strains. Broader surveys are needed to define MAP strain diversity in Japan and improve control strategies.