Tuberculosis Flashcards

Question

what do trehalose di-mycolate (Cord factor) do in the cell wlal of mycobacteria

Answer 1

Trehalose di-mycolate (cord factor) Inhibits phagocyte chemotaxis, activation, phagosome-lysosome fusion and digestion

Answer 2

Lipoarabinomannan (LAM) Prevents phagocyte activation and digestion within the phagocyte

Answer 3

Mycosides Prevent intracellular killing and digestion

Answer 4

Cell wall antigens in general induce delayed type hypersensitivity (DTH)

Answer 5

the ability to mount an effective activated macrophage response

Answer 6

1. Infects, killed by immune response, no disease 2. Infects, lies dormant for many years, no disease (infection contained) (most common) 3. Infects, lies dormant for many years, re-activates and causes acute disease 4. Infects, causes rapid acute disease, may disseminate (children, immunocompromised, HIV)

Answer 7

Antibody response irrelevant to protection * Th1 (CMI) required to limit the disease and provide protection Immune status of host important * Active response results in lymphocyte infiltration, central necrosis in the lesion, tubercule many limited by a fibrin capsule Response kay kill the bacteria but often is only able to restrict the disease Reactivation occurs with stress/immunosuppression IFN gamma from CD4 lymphocytes activates macrophages to all intracellular mycobacterial infected cells CD1 restricted T cells recognize glycolipids Exposure to environmental mycobacteria provides some cross-protection which may limit the disease caused by virulent species (also complicates skin testing)

Answer 8

Is promoted by high densities of animals and immune suppression

Answer 9

Leads to tubercules in the lungs and associated lymph nodes (bronchial and retropharyngeal)

Answer 10

Spread to intestine (via sputum) and serosal surfaces Pleural lesions * Pearls disease Further disease spread (usually hematogenous) to liver, spleen, kidney, brain etc

Answer 11

Antibiotic treatments are long term and very expensive * Tuberculin testing and culling of exposed animals

Answer 12

multifocal to coalescing caseous granulomas

Answer 13

Cattle transmit infection to cattle via infected respiratory droplets --\> Resp route Badgers transmit M. bovis between themselves by respiratory route and biting Mums transmit to cubs Cattle may get M. bovis from badgers via grazing on pasture contaminated with badger urine, feces and bronchial pus or badgers urinate and defecate in cattle feeders Aerosol transmission via coughing may be possible or via dried badger saliva in cattle houses This may apply to battle to badger transmission

Answer 14

Badger culling has significant impacts on the incidence of bTB in cattle Culling of badger in define areas prevents infection on farms Culling badgers in areas with no barriers makes survivors wander and spread infection further Need vaccine for cows and wildlife BCG works well in badgers both IM and orally BCG in neonatal calves, adults?

Answer 15

Will protect cattle against TB The degree of protection varied considerably between studies Neonatal or young calves can be protected at least as well as older calves Systemic as well as mucosal (oral or endobronchial) delivery of BCG leads to protection Its (or another better vaccine) use in cattle and other domestic animals will require the development of a diagnostic test that can be used alongside vaccination to differentiate vaccinated and infected cattle (DIVA test)

Answer 16

Culling — Ireland (with vaccination of badgers using BCG) Culling — England (achieve certain percentage in high TB areas to decrease disease? Vaccination of badgers — Wales Badger vaccination across UK? — needles, baits? Cattle vaccination

Answer 17

Immunological detection Microscopy Culture

Answer 18

Tuberculin testing using PPD (purified protein derivative) from the relevant bacterial species PPD contains a mixture of proteins, carbohydrates, lipids and DNA Gamma interferon assay

Answer 19

**Microscopy** * Ziehl Nielsen staining, rhodamine/auramine fluorescent stain) of appropriate specimens from site of infection **Culture** * Lymph node, tissue lesions, sputum, aspirates, milk * Decontamination of specimens with sodium hydroxide * Lowenstein Jensen medium (slants) incubated for up to 8 weeks * ID by growth rate, colonial appearance, biochemical techniques, now increasingly molecular techniques (DNA probes, specific species primers for PCR)

Answer 20

The tuberculin test is carried out at 1, 2, 3, or 4 year intervals depending on the freq of TB in the area Animal ID and two sites prepared on the side of neck Inject PPD Re-measure fold after 72 hours If reaction to M. bovis PPD is 5mm greater than to M. avium then defined a reactor If 1-4mm then retested within 40-60 days Measure lymphocyte infiltration into site If previous exposure increased TB specific lymphocytes in lesion hence increase in size Rest of herd analyzed using ‘severe interpretation’ which is 3mm

Answer 21

non human primates, cattle and pigs infection is confined to the lymph node causes disseminated disease in HIV/AIDs patients

Answer 22

thickened corrugated infection of ileum

Answer 23

Leprosy in humans and primates, cutaneous lesions and nerve damage Irradiated mice foot pads, nine banded armadillos **Tuberculoid leprosy:** * Little disfigurement * Few organisms in well-contained granulomatous lesions in tissue **Lepromatous leprosy:** * Disfigurement, nodular swellings full of bacteria * Anesthesia * Shortening of toes and fingers in response to repeated unfelt trauma; spontaneous

Answer 24

Skin lesions (especially on head and tail) of cats and rodents

Answer 25

Skin, nodules (skin granulomas) which can ulcerate mainly humans

Answer 26

Fatal infections common in poikilotherms Fish tank/swimming pool granuloma from humans