Mycobacterial Diseases

Question 1

how do cattle get Mycobacteria spp?

Answer 1

inhalation
ingestion

Question 2

what is the hallmark of mycobacterial disease in humans and animals?

Answer 2

granuloma

Question 3

what are some common themes of all mycobacterial diseases?

Answer 3

emaciated on physical exam
nodules anywhere on body: physical exam, granulomas on necropsy
thickened tissues: physical exam and necropsy

Question 4

mycobacteria possess virulence factors that cause ______________________________

Answer 4

necrosis/inflammation

Question 5

what virulence factors do mycobacteria have that promote necrosis?

Answer 5

cell wall: trehalose dimycolate
secreted proteins: ESAT-6, CFP-10

Question 6

how do mycobacteria resist antimicrobial effects of phagosomes?

Answer 6

inhibit phagolysosome fusion: poor lysosome acidification

Question 7

how do mycobacteria impair antigen presentation?

Answer 7

diminish expression of MHCI and MHCII

Question 8

how do mycobacteria live outside of cells?

Answer 8

necrotic centers of granulomas

Question 9

common TB diagnostic tests detect ___________________________________

Answer 9

memory T cell responses

Question 10

how do we interact with bovine tuberculosis and cattle now?

Answer 10

test live cattle to identify “reactors” and slaughter
look for granulomas at slaughter: culture, PCR

Question 11

what is the major reservoir of bovine tuberlucosis in the UK and ireland?

Answer 11

badgers

Question 12

what is the reservoir of bovine tuberculosis in the US?

Answer 12

white tailed deer

Question 13

what type of pneumonia does tuberculosis cause?

Answer 13

granulomatous pneumonia

Question 14

what pathogen causes bovine tuberculosis?

Answer 14

Mycobacterium bovis

Question 15

what is the route of infection of Mycobacterium avium subspecies paratuberculosis in ruminants?

Answer 15

fecal-oral: milk from dirty teat
GI tract
Peyer’s patches
macrophages
chronic granulomatous enteritis
wasting
death

Question 16

what is the signalment and signs of Johne’s disease in cattle?

Answer 16

> 2 years old, cachexic
diarrhea, chronic or intermitteent
no mucus, no blood, no tenesmus
no fever

Question 17

is there a vaccine for Mycobacterium avium subspecies paratuberculosis in cattle?

Answer 17

yes, but not great

Question 18

when is Johne’s disease typically diagnosed?

Answer 18

more than 2 years old

Question 19

why may animals take years to show symptoms of Johne’s disease?

Answer 19

slowly progressive, wasting

Question 20

why must age be taken into account when choosing diagnostic tests?

Answer 20

many tests are less sensitive for animals <18 months

Question 21

who can get Mycobacteria spp via ingestion?

Answer 21

humans
cattle
cats

Question 22

who can get Mycobacteria spp via contact?

Answer 22

cats
humans

Question 23

what does necrosis contribute to?

Answer 23

macrophage death
granuloma necrosis
lung tissue infarction
cavitation
neutrophils
fibrosis

Question 24

how do Mycobacteria achieve metabolic quiescence (latency)?

Answer 24

survives nutrient deprivation and hypoxia

Question 25

what protective enzymes do Mycobacteria produce?

Answer 25

arginases degrade reactive nitrogen species

Question 26

how do Mycobacteria mannipulate phagocytosis?

Answer 26

entry through mannose receptor is anti-inflammatory

Question 27

Mycobacteria can induce antigen-specific tolerant __________

Answer 27

T cells

Question 28

what does an indirect ELISA detect for M bovis?

Answer 28

antibodies against MPB93 and MPB70

Question 29

what is the reservoir in South Africa of tuberculosis?

Answer 29

cape buffalo

Question 30

what has Mycobacterium tuberculosis shown?

Answer 30

reverse zoonosis captive elephants exposed by handlers

Question 31

what are the concerns with tuberculosis?

Answer 31

affects many species public health concern wildlife conservation concern food animal concern

Question 32

what is the transmission route for Johne's disease (Mycobacterium avium subsp paratuberculosis)?

Answer 32

fecal-oral

Question 33

how is diagnosis of Johne's disease different than other mycobacterial diseases?

Answer 33

test of cell-mediated immunity often does not work well

Question 34

what are the preferred ways to diagnose Johne's diseasse?

Answer 34

PCR or culture PCR: IS900 unique genetic element in Mycobacterium avium subsp paratuberculosis