First report on molecular identification and fenbendazole resistance against Baylisascaris transfuga infection in Melursus ursinus (sloth bear)

Based on morphometric findings and polymerase chain reaction amplification of internal transcribed spacer regions (ITSs), the worms and eggs retrieved from sloth bear (Melursus ursinus) kept at Mahendra Mohan Choudhury Zoological Park, Chhatbir (Punjab, India) were delineated as Baylisascaris transfuga. Therapeutic intervention with fenbendazole à 10 mg/kg body weight for three consecutive days, associated with complete disinfection of the enclosures, proved to be effective for the first few days with the reduction of eggs per gram (EPG) of faeces from 2800 (zero day) to 400 (14.28 %), 700 (25 %) and 800 (28.57 %) on days 1, 4 and 7 post treatments, respectively. The intensity of EPG increased to 2400 (85.71 %) on day 21 post treatment with respect to day zero. A modified schedule with fenbendazole à 15 mg/kg body weight for first three days followed by 10 mg/kg body weight for next three days proved to be effective thus indicating the development of resistance. The study places on record the molecular characterisation of B. transfuga from sloth bears and development of resistance against fenbendazole.