Human-to-Bovine M. Tuberculosis Transmission A Reverse Zoonosis


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GRF 2nd One Health Summit 2013: Presentation by Prof. Reza Nassiri, Michigan State University

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Human-to-Bovine M. Tuberculosis Transmission A Reverse Zoonosis

  1. 1. Human-to-Bovine M. Tuberculosis Transmission A Reverse Zoonosis L. Gunaseelan, V. Bhnurekha, G. Pawar, R. Nassiri Department of Veterinary Public Health and Epidemiology, Madras University, and Tamil Nadu Veterinary and Animal Sciences University, Chennai, India and Institute of International Health, Michigan State University East Lansing, Michigan, USA PRESENTER: Prof. Reza Nassiri
  2. 2. Introduction • Zoonosis constitute 60-65% of all known infectious diseases, 75% of the infections considered “emerging” are zoonosis. • Historically the link between animal and human tuberculosis has always been strong. • Zoonotic Mycobacterium tuberculosis is both a public and One Health threat.
  3. 3. Introduction • Transmission from animals to human (and vice versa) in developing countries remains a significant public health danger, most from consumption of unpasteurized milk, consumption of daily products made from unpasteurized milk. • Detection of mycobacterium through molecular epidemiology techniques is an important step in disease characterization.
  4. 4. Introduction • M. tuberculosis, M. bovis and M. africanum together with Mycobacterium microti (associated with infection of rodents) from a very closely related phylogenetic group may be referred to collectively as the M. tuberculosis complex (MTBC).
  5. 5. Central Hypothesis of This Study • Reverse zoonotic tuberculosis should be investigated through the means of molecular epidemiology to assess the risk and to better understand the dynamics of the disease transmission with respect to identification of types and sub-types. • Our hypothesis would allow subsequent surveillance, control, preventive, and interventional measures.
  6. 6. Overall Aim • To make an assessment of zoonotic tuberculosis transmission (Human-to-animal; reverse zoonosis) in Chennai, India. • Significance: • Application of molecular epidemiology as a tool in zoonotic TB surveillance, screening and detection in both human and animal populations.
  7. 7. Samples • A total of 181 bovine milk samples and 113 pre-scapular lymph node biopsy samples were collected • Teaching and Research hospital (Madras Veterinary College, Chennai) • University research farm • Two slaughter houses in Chennai districts
  8. 8. Methods • Acid fast staining • Florescent staining • Culture • Molecular confirmation by MTBC genus PCR • Targeting IS6110 region
  9. 9. Methods • Molecular confirmation by multiplex PCR to differentiate M. tuberculosis and M. bovis • 3 primers: CSB1 Common FP, CSB2 M. bovis, CSB3 M. tuberculosis • Phylogenetic tree analysis using MEGA5 software
  10. 10. Results Test employed Milk Positive Tissue/PSLN Positive aspirate ZN acid fast staining 181 0 123 0 Auramine staining 181 0 123 0 Culture 181 1 123 0 IS6110 PCR 181 3 123 0 Multiplex PCR 181 3 123 0
  11. 11. Results
  12. 12. Discussion • Comparing all diagnostic tests for TB detection, in-house PCR targeting the IS6110 and multiplex PCR provide much higher sensitivity. • Phylogenetic tree analysis and gene sequences of bovine isolate 1,2 and 3 matched human sputum isolates from Kerala, India – Madhavilatha et al, 2012, J. Bacteriol.
  13. 13. Discussion • Transmission of Mycobacterium tuberculosis from Human to Cattle – Natjaz Ocepek et al, J. of Clinical Microbiol, July 2005 • Described the first transmission of Mycobacterium tuberculosis from human to cattle using molecular typing of isolates involved in the transmission. • IS6110-based restriction fragment length polymorphism analysis showed that the isolates from the cattle and a farm worker who suffered from pulmonary tuberculosis 1 year prior to the case were the same strain.
  14. 14. One Health Implications • Stop the cycle of transmission between humans and cattle, and vice versa. • Train stakeholders for best practices in disease screening, detection, and cross-species transmission interventional strategies. • Develop a comprehensive communication strategy to increase reverse zoonotic TB awareness and to galvanize political will.
  15. 15. Summary • We have shown the presence human M. tuberculosis in animal milk and lymph biopsies. • Our study which identifies molecular types of M. tuberculosis complex strains from cattle milk, establishes a baseline for an effective public health and One Health control measures of tuberculosis in both humans and animals with implications for policymaking.