Studies on Zoonotic Tuberculosis with special reference to Molecular detection in cattle and in contact humans in Chhattisgarh, India

Abstract

The present study was carried out with the objective to estimate prevalence of Bovine Tuberculosis (BTB) in cattle and assess the status of BTB among persons who are in contact with cattle, in Chhattisgarh. A total of 470 samples comprising of 250 milk, 100 blood, and 120 Pre-scapular lymph node aspirate (PSLN) were collected from different organized and individual/ household farms of Durg, Rajnandgaon, Raipur and Bilaspur districts of Chhattisgarh and subjected to acid fast and auramine staining. Out of these 250 milk samples 24(9.6%) were found positive by acid fast staining or ZN staining and 31(12.4%) were detected positive by auramine staining. Out of total 250 milk, 100 blood and 120 PSLN samples, subjected to multiplex PCR (m-PCR), 40 samples [27(10.8%) milk, 5(5%) blood and 8(6.6%) PSLN] were found positive for M. bovis and percent positivity was estimated as 8.5%. The comparative evaluation of acid-fast staining, auramine staining and multiplex PCR revealed that out of 250 milk samples tested, 24(9.6%) samples were positive by acid fast staining, 31(12.4%) were positive by auramine staining and 27(10.8%) were positive by multiplex PCR. A comparative evaluation of acid fast and auramine staining was done for screening of BTB to assess the sensitivity and specificity of the technique and the results showed that 31(12.4%) positive samples were detected by auramine staining, whereas, only 24 (9.6%) samples were found positive by acid fast staining. Taking auramine staining as gold standard, the sensitivity and specificity percentage of 61.3% and 97.7% respectively were found for acid fast staining. Prevalence of BTB in organized farms and individual/household farms was estimated and results revealed that total of 33(10.8%) samples were positive from organized farms whereas 7(4.2%) were positive from individual/household farms. The prevalence of BTB in cross-bred and indigenous/ non-descript cattle was assessed and total 22(8.9%) samples in cross bred animals were positive whereas only 18(8%) were positive in non descript/indigenous animals. Zoonotic TB among persons who are in contact with cattle was determined by screening of 80 blood samples of human subjects from Durg, Rajnandgaon and Raipur districts, by m- PCR. Results showed 9(11.2%) positive samples for M. bovis from Durg District.