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28 Cards in this Set
- Front
- Back
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What are the two subspecies of Mycobacterium avium |
subspecies avium - - -TB in chickens, other birds, some animals & in (immunocompromised) humans. subspecies paratuberculosis – paratuberculosis (Johne’s Disease) of ruminants; infection of humans is controversial |
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What is the other name for the “Acid fast” stain? |
Ziel - Neelsen method |
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What does the acid fast satin consist of? What is the counterstain? |
Carbolfuchsin Methylene blue |
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What does the Acid-fast/Ziehl-Neelsen method stains? |
lipid (up to 60% of cell wall) |
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What is the Unique fatty acid present in mycobacterium? |
mycolic acid |
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What are some characteristics of Mycobacteria |
Non-motile aerobes •Do not form spores •In animals, straight or slightly curved rods, 1-4 x 0.5 μm •In culture, sometimes filamentous •Multiply slowly (14 - 24 hrs) •Primary culture ≥ 3 - 4 weeks Beaded staining property |
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What are Mycobacteria resistant to? |
heat (killed by pasteurization) desiccation fairly great most aqueous disinfectants–Acids and bases (0.1 M NaOH @ 37º) |
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What are Mycobacterium susceptible to? |
•Phenol or alcohol kill •Sensitive to direct sunlight |
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How much of world’s population is infected with TB? Each year, how many people around the world become sick with TB? |
1/3 9 million |
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What M. tuberculosis strains are on the rise world-wide (but not in the US so far)? |
Multi-drug resistant (MDR) and extensively drug resistant (XDR) |
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What is the susceptibility of all TB strains in humans? |
Progressive disease |
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Which strains of mycobacteria cause progressive disease in cows and pigs? What do the others cause? |
M. Bovis M. Avium and M. Tuberculosis cause lesions |
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Which strain of mycobacteria causes progressive disease in horses? |
M. Bovis |
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Which strain of mycobacteria causes progressive disease in dogs? Most likely, where did they get this disease? |
M. Tuberculosis From and infected person with TB |
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Which strain of mycobacteria causes progressive disease in cats? |
M. Bovis |
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Which strain of mycobacteria causes progressive disease in elephants? What percentage of elephants in the US are infected? |
M. Tuberculosis 11.3% |
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What are the routes of infection and location of lesions for mycobacteria? |
Inhalation--lungs, lymph nodes of head and thorax• Ingestion--intestinal tract, lymph nodes, liver, and spleen–large numbers required–important route before milk pasteurization• Percutaneousinfection (after skin inoculation) --skin, skin draining lymph nodes–Very rare! |
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Lung tuberculosis –what does it look like? |
Granulomas Massive tissue necrosis and dissemination "military TB" |
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What is the TB vaccine used for? |
NOT used in animals; mostly effective against childhood M. tuberculous meningitis and miliary disease; not very effective in prevention of adult pulmonary TB; used in countries of higher TB prevalence; can cause false positive TB skin test. |
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What is the Bacillus Calmette Guerin (BCG) vaccine developed from? |
M. Bovis |
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What are the diagnostic tests for Mycobacteria? |
Chest X-ray (more common in humans)• Microbiological studies (Acid-Fast staining and culture)• PPD (Purified Protein Derivative) skin test (most commonly used in humans and animals; false negative and false positive results)• IFN-γ release assays (fewer false positive results) |
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Skin tests and IFN-γ assays are based upon what immune response to the mycobacterium infection? |
Type 4 Hypersensitivty |
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Explain the immune response of M. TB and bovis? |
Infected macrophages and dendritic cells activate CD4 T cells. Th1 polarization (IFNReleased IFNγ!) γ and TNFα at infection site activates macrophages. Important for granuloma maintenance (containment of live bacteria) |
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What are the advantages of testing for Mycobacteria with IFN-γ release assays? |
Uses blood samples and tests IFN-γ release upon stimulation with M. tb specific antigens (also available for M. bovis and M. avium)• Detects latent TB. •Fewer false positive results.• Result is not affected by BCG vaccination |
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How is Mycobacteria controlled in cattle? In poultry? |
Cattle–TB test & elimination of reactors–Most positive cattle show no lesions–Examination of carcass at slaughter (slaughter surveillance)• Poultry–No longer serious problem for commercial raisers–takes 1 year for open cases to develop |
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What is the therapy for Mycobacteria? |
Food animals: no therapy. Euthanasia. (State vet in charge of official diagnosis and action) Pets: treatment not recommended. Beware of state regulations. Antibiotic treatment for a total of 6combination of 4 first line drugs: Isoniazid, rifampin 12 months (or longer) with a , ethambutol, pyrazinamide. Additional/alternative drugs may be used for the treatment of MDR or XDR TB. |
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What is the biggest challenges to the Bovine TB program? |
Today’s cattle industries are specialized and often move animals among multiple premises, leading to increased risks of TB transmission. |
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What is the cause of Johne’s disease (paratuberculosis)? |
Mycobacterium avium subspecies paratuberculosis (MAP) |
