Objective: To understand the genetic diversity of Mycobacterium avium subspecies paratuberculosis (MAP) isolates recovered from domestic and wild ruminants, commercial milk, and human beings in North India.
Methods: Genotyping of MAP isolates (N=117) recovered from animals, commercial milk, and human beings in different regions of North India between 1998 and 2007 was carried out using IS1311 PCR-restriction enzyme analysis (REA) and short sequence repeat (SSR) typing (G and GGT repeat loci).
Results: Of the 117 MAP isolates recovered from North India, bison-type was the predominant (83.8%) genotype followed by cattle-type (16.2%). Bison-type was the exclusive genotype recovered from goats, sheep, buffaloes, and blue bulls. However, both bison-type and cattle-type genotypes were recovered from cattle, humans, and commercial bovine milk samples. The relative distribution of the two genotypes was different in the different regions. Bison-type was the major genotype at the Central Institute for Research on Goats (CIRG), Akos, Ajmer, and Mathura, whereas, cattle-type was the major genotype from New Delhi and Agra. SSR typing of these isolates revealed that all MAP bison-type isolates had an identical profile (7g4ggt) with respect to G and GGT repeat SSR loci. In this study the sheep-type genotype was not found in North India.
Conclusions: This study is the first from India to report the presence of two kinds of MAP genotypes (cattle-type and bison-type). However, non-reporting of the sheep-type genotype may not mean that it is absent in North India; the use of multiple culture media to recover MAP from clinical samples for future investigations is advised.