Serological and molecular evaluation of Mycobacterium avium subspecies paratuberculosis (Johne's disease) infecting riverine-type water buffaloes (Bubalus bubalis) in the Philippines.

Mycobacterium avium subsp. paratuberculosis (MAP) is the causative agent of Johne's disease and a possible cause of Crohn's disease in humans. A total of 70 blood and fecal samples were collected from water buffaloes in selected municipalities of Nueva Ecija for ELISA and qPCR assay. Results revealed presence of antibodies of MAP in 3 serum samples for ELISA. The qPCR assay was carried out using standard curve method targeting the MAP specific insertion element IS900. Results revealed that 10 of the samples were positive for MAP DNA in qPCR. ELISA was able to detect antibodies for MAP showing 2.48% infection rate among the 70 buffaloes tested using blood serum samples. On the other hand, qPCR was able to detect MAP using IS900 showed 14.28% infection rate among buffaloes tested using fecal samples. Nucleotide sequence of isolated MAP showed high homology (99-100%) among the reported MAP isolates in the GenBank.