Bovine Tuberculosis Monaya Ekgatat NIAH TBTB

- Introduction - Etiology & Epidemiology - Clinical Signs - Post mortem lesions - Diagnosis - Public Health - Prevention and control Bovine Tuberculosis NIAH

Zoonosishuman - aerosol - ingestion Developed countries - reduced prevalence Less developed countries - still common - economic loss Introduction Control relies on - early diagnosis - removal of infected animal - tracing - exposing infected cases NIAH

Etiology and epidemiology Agents Mycobacterium tuberculosis (human) Mycobacterium bovis (animal) Mycobacterium avium (bird) NIAH

Mycobacterium tuberculosis complex (MTB. Complex) M. caprae M. tuberculosis M. caprae M. pinnipedii M. bovis M. pinnipedii M. africanum M. canetti M. microti Etiology and epidemiology

Mycobacterium bovis Can survive for several months in the environment (cold, dark and moist condition) o C survival time days Dry or moist soil (34 o C) : 4-8 weeks Summer : 4 days

Maintenance hosts for M. bovis - cattle - buffalo Reservoir hosts - brush-tail possum (New Zealand) - badger (United Kingdom, Ireland) - deer (United States) - bison (Canada) - greater kudu, common duiker African buffalo, warthogs (Africa) Etiology and epidemiology NIAH

Badger

African buffalo Warthog

Common duiker Greater kudu

Brush-tail possum

Etiology and epidemiology Transmission Respiration----aerosal (short distance) Ingestion ( unpasteurized milk) Source of infectious bacteria - respiratory secretion - feces - milk - (urine) - vaginal secretion - semen NIAH

Incubation Period 3 weeks – years: under natural condition Morbidity and Mortality 1-2 animals = % infected = % developed gross lesions Severity - dose of agents - individual immunity Mortality : rare

Clinical Signs Chronic ( rare: acute & rapidly progressive) Early infection ---- asymptomatic Late stage: symptomatic - progressive emaciation - fluctuating fever - weakness - inappetite - moist cough (pulmonary involve) - dyspnea No specific signs Asymptomatic and anergic carriers (ill: stress, old age) NIAH

Post mortem lesions NIAH

Lymphnodes: calcified

NIAH

Tubercles in liver

NIAH

Mesenteric lymph node

Diagnosis Clinical signs (lacking) Clinical signs (lacking) Laboratory diagnosis 1. Identification of the agent a) Microscopic examination b) Culture of M. bovis (3-6 weeks) - biochemical tests - culture characteristics c) Nucleic acid recognition methods NIAH

2. Delayed hypersensitivity test Tuberculin test : SID, SCITT 3. Blood-based laboratory tests a) Gamma-interferon assay b) Lymphocyte proliferation assay c) ELISA (late stages of infection, anergic cattle) Diagnosis

Presumptive Diagnosis Histopathology Microscopic demonstration of acid-fast bacilli Direct smear from clinical samples/tissues and stained with Z-N stain, fluorescent acid-fast stain or immunoperoxidase

- Contagious bovine pleuropneumonia - Pasteurella or Corynebacterium pyogenes pneumonia - Aspiration pneumonia ( secondary infection) - Traumatic pericarditis - Caseous lymphadenitis or melioidosis (small ruminant) - Chronic aberrant liver fluke infestation NIAH Differential Diagnosis

Laboratory Diagnosis 1. Identification and isolation of the agent NIAH

M. bovis: Cord Formation

NIAH M. bovis: granule in P&B

NIAH Immunohistochemistry

NIAH DNA - hybridization

ELISA: Detection of MTB complex NIAH

The immune system : Antigen Antigen presenting cells (Macrophages & reticulocites) Humoral immunity B-lymphocytes Plasma cells antibodies Lymphokines cytooxicity T-lymphocytes Cell mediated immunity Diagnostic measures of an Immune response ELISA Skin test / Lymphocyte stimulation / Gamma-interferon Memory

Antigen:Bov. PPD 0.1 ml(not more than 0.2 ml) = 2,000 IU – 5,000 IU Work plan 0 h hrs 2.Tuberculin test 1 st measure injection 2 nd measure Negative reaction < 2 mm w/o local clinical signs Inconclusive reaction 2-4 mm w/o local clinical signs Positive reaction ≥ 4 mmwith or w/o local clinical signs (one fold + ≥ 8 mm) Retest: after days (cattle), 120 days (deer) NIAH

Cervical Test

Caudal fold Test

Axillary Test

Base of the ear

Anywhere

Tuberculin test NIAH

Positive reaction

NIAH Tuberculin test at cervical

NIAH

Deer: Tuberculin test (cervical)

NIAH

a) Gamma-interferon assay (IFN) a) Gamma-interferon assay (IFN) – early detection NIAH 3. Blood-based laboratory tests

NIAH

IFN Assay

b) Lymphocyte proliferation assay Antigen : PPD-Bov, PPD-Avi Not used for routine diagnosis - long incubation times - use of radio-active nucleotides Expensive

NIAH c) ELISA: complementary test

d) Chromatographic Immunoassay

Chromatographic Immunoassay

Samples Collection Live animal - body fluids: microbiological examination - blood samples: IFN, lymphocyte proliferation - serum: ELISA Necropsy - abnormal lymph nodes - affected organs (lung, liver and spleen) For bacteriology and histopathology

Public Health Due to M. bovis : very rare Asymptomatic Localized: lymph nodes, skin, bones and joints, genitourinary system, meninges or respiratory system

Prevention and Control Sanitary Prophylaxis - Tuberculin Test slaughter - Re-testing schedule for high risk herds - Animal movement control, identification and surveillance - Disinfection Effective disinfectants: 5 % phenol, iodine solution, glutaraldehyde and formaldehyde Environment : 1% sodium hypochlorite (long contact time) NIAH

-Quarantine measures -Slaughter inspection surveillance and trace - back -Surveillance in other animals -Pasteurisation of milk Medical Prophylaxis No chemophophylaxis or treatment Prevention and Control NIAH

Control Test-and-slaughter (domestic animals) Test-and-segregation Affected Herds - re-tested periodically

Thank you for your attention