Comparison of interferon-gamma, neopterin, interleukin-10 and antibody levels in sheep with and without Mycobacterium avium subspecies paratuberculosis

Abstract Mycobacterium avium subspecies paratuberculosis (MAP), responsible for paratuberculosis, causes serious economic losses in the livestock industry worldwide. To develop accurate control strategies against MAP, it is necessary to understand the pathological basis of the disease and identify new diagnostic markers for the detection of infection. In this study, commonly used diagnostic tests for the detection of MAP infection were compared and the agreement between these tests was evaluated. The measurement of interleukin-10 (IL-10) and neopterin levels in the serum were also assessed for their potential to be used in the detection of MAP infection in sheep. The diagnostic tests revealed that 73 (48.66 %) of 150 sheep were MAP-positive. The highest proportion of positive sheep were determined by Ziehl-Neelsen (ZN) staining (27.33 %) and direct fecal polymerase chain reaction (PCR) (26.66 %), followed by interferon-gamma enzyme-linked immunosorbent assay (ELISA) (22 %), antibody ELISA (10.67 %) and fecal culture (3.33 %) methods. A significant, almost perfect, agreement was found between ZN staining and direct fecal PCR test (κ: 0.882, P