Interspecies Sharing of “Indian Bison Type,†A Novel Predominant Genotype of Mycobacterium Avium Subspecies Paratuberculosis between Naturally Infected and Endemic Flocks of Bharat Merino Sheep and a Colony of Rabbits (Oryctolagus Cuniculus) Raised on the

Abstract

Mycobacterium avium subspecies paratuberculosis (MAP) is endemic in domestic and wild ruminants and non-ruminant animal population of India. Native “Indian Bison type” genotype of MAP has emerged as the predominant genotype with an impressive list of hosts cutting across species and has emerged as a major animal pathogen with significant zoonotic concerns. The present study has for the first time investigated the status of MAP infection in a colony of domesticated rabbits (Oryctolagus cuniculus) that shared fodder and water resources from the premises home to Bharat Merino sheep unit consisting of 500 animals endemic for Johne’s disease in Manavannur, Tamil Nadu region of South India for the last 40 years. Consequently, for three years (2009 to 2011), a total of 77 fecal samples were collected from the rabbit colony (Soviet Chinchilla and New Zealand White Gaint) and were screened for the presence and genotype of MAP using microscopic examination and specific IS900 and IS1311 PCR-REA. Of the total 77 samples, 26 (33.76%) and 6 (7.8%) were positive for MAP using microscopic examination and direct IS900 PCR, respectively. Further genotyping of the IS900 positive DNA exhibited presence of Indian Bison type genotype which has also been recovered from the sheep flock and bison (wild ruminant) sharing the same premises. Presence of identical genotype (Indian Bison type) of MAP in Oryctolagus cuniculus (domesticated rabbit), bison and sheep flock suggests inter-species transmission and sharing of MAP and raises serious concerns of the rabbit colony acting as the non-ruminant multiplier/reservoir host of MAP.