Molecular Detection of Mycobacterium avium subsp. paratuberculosis by Targeting IS900 Insertion Sequence in the Samples of Dairy Cattle of Assam, India

Johne’s disease (JD), also referred to as paratuberculosis, is caused by Mycobacterium avium subsp. paratuberculosis (MAP). It is a chronic disease of ruminants that primarily affects the enteric system and is seen worldwide. The study aimed towards molecular detection of MAP in bovine samples. A total of 220 bovine samples (intestinal tissue-60, faecal-60 and milk-100) were collected from cattle herds and slaughter point and were examined for detection of MAP targeting the IS900 insertion sequence through conventional PCR. MAP DNA was detected in 7 intestinal tissue samples (11.66%) and 1 faecal sample (1.66%). Only 3/60 (5.0%) intestinal tissue samples could be detected as acid fast bacilli by Z-N staining. The results were further re-confirmed by nBLAST analysis following Sanger dideoxynucleotide sequencing. The results indicate the presence of MAP-infections in dairy herds of the study area, Assam. This may be the first report of molecular detection of MAP in bovine intestinal tissue and faecal samples in Assam, Northeast India as per our literature search. Additional research is required across all Northeastern regions of India to determine the precise prevalence of the pathogen and to mitigate the spread of the disease.