Abstract

Aim: To investigate the incidence of bovine tuberculosis (BTB), an old chronic disease having zoonotic potential, covering four (4) districts in Gangetic delta region of West Bengal, India region and to find out the prevalence in organized as well as backyard herds and variation in relation to their age, sex and breeds.
Methods: The incidence of bovine tuberculosis (BTB) in exotic and indigenous breeds of cattle (n=173) of various age groups was investigated employing tuberculin (single intradermal tuberculin and comparative cervical tuberculin) tests and gamma interferon assay. Further, milk samples (n=96) from milching animals and ante-mortem (n=519) samples (nasal swab, buccal swab and aspirates from pre-scapular lymph nodes) were also screened employing bacteriological and molecular techniques.
Results: In total, 36 (25.4%) animals from organized and one (3.2%) from backyard farming sector were found positive to BTB. PCR of milk samples based on 16S rRNA amplified the 1030 bp band in four samples indicating them belonging to genus Mycobacterium. Species-specific primers used to differentiate between Mycobacterium bovis and M. tuberculosis, confirmed the presence of M. bovis. Prevalence of BTB in exotic cross bred animals (34.6%) was significantly higher (p< 0.001) compared to indigenous cattle (10.5%). Further, gender-wise analysis of data with respect to BTB revealed higher positivity (P

Key words: Bovine tuberculosis, cattle, prevalence, West Bengal, India