Bovine tuberculosis is a chronic bacterial disease caused by Mycobacterium bovis. It can be transmitted to humans through direct contact with infected cattle or consumption of unpasteurized milk and milk products. The current study was performed to assess whether raw milk produced in three large scale dairy farms in Central Province of Sri Lanka contain any M. bovis. Raw milk samples were collected from 330 cows representing 230 single intradermal comparative cervical tuberculin test reactors and 100 none-reactors. All milk samples were cultured on Lowenstein Jensen medium with/ without sodium pyruvate for the isolation of Mycobacterium spp., and slopes were observed for the occurrence of growth daily for the first week and then at weekly intervals for 8 weeks. Direct Polymerase Chain Reaction (PCR) was performed simultaneously on all milk samples to detect M. bovis after extracting DNA with a commercial kit. The minimum detection level of M. bovis for PCR in milk was 200 CFU/mL. Only two milk samples from reactive cows were positive for acid fast bacilli. However, their cultures were confirmed as non-tuberculous mycobacteria by PCR. Consequently, all milk samples were confirmed negative for M. bovis according to direct PCR. It was concluded that the milk samples from three large scale dairy farms in Central Province of Sri Lanka did not contain M. bovis.

Mycobacterium bovis causes bovine tuberculosis (BTB) primarily in cattle. All mammals are susceptible to this zoonotic disease and it had been reported from the Central and North Western provinces of Sri Lanka. Abattoir monitoring is usually used for BTB surveillance in endemic countries. However, proper ante-mortem inspection of cattle and proper meat inspection is practiced only at a few abattoirs in Sri Lanka. The objective of this study was to conduct a preliminary assessment of BTB incidence among cattle used for beef production at two abattoirs in Western (WP) and North Central (NCP) provinces in Sri Lanka. Randomly collected 115 lung samples (WP = 45; NCP = 70) were tested using direct acid-fast staining, culture on Lowenstein Jensen medium, histopathology and PCR. Mycobacterium tuberculosis complex was detected in 7.0 % of the samples by PCR conducted using DNA extracted directly from samples. Only 5.2 % of the samples (4.45 % from WP and 5.7 % from NCP) were positive for M. bovis specific PCR. Only one (0.87 %) PCR positive sample from NCP had a granuloma on histopathological observation, suggesting relatively low incidence of BTB among the cattle processed at these abattoirs. Mycobacterium bovis isolates were not recovered and acid-fast bacilli were not observed in direct smears. Initiating proper meat inspection at all abattoirs in the country along with increased BTB surveillance capacity of the national veterinary service are required to mitigate this risk. Further studies are essential to determine the exact prevalence of BTB in Sri Lanka and to identify any wildlife reservoirs of BTB in the country.