Mycobacteria

Question 1

what are the general characteristics of Mycobacteria? (aerobic status, shape, spores?, gram/acid?, heat sensitivity?)

Answer 1

obligate aerobes
bacilli
non-spore forming
acid-fast bacteria
heat sensitive

Question 2

why does Mycobacterium not take up gram stain dyes?

Answer 2

high concentration of mycolic acids and lipids

Question 3

what is an effective way to kill Mycobacterium?

Answer 3

pasteurization b/c bacteria is heat sensitive

Question 4

How long does it take for pathogenic mycobacterium to grow?

Answer 4

3-6w

Question 5

what stain is used to differentiate mycobacteria from other bacteria?

Answer 5

Ziehl-Neelsen

Question 6

Are there few or many mycobacterium species?

Answer 6

many many many

Question 7

How is mycobacterium transmitted?

Answer 7

inhaled and ingested

Question 8

List the clinically relevant veterinary mycobacterial series?

Answer 8

bovine tuberculosis, Johne’s disease, poultry tuberculosis, feline leprosy

Question 9

what is the causative agent of bovine tuberculosis?

Answer 9

Mycobacterium bovis

Question 10

what are the main concerns with bovine tuberculosis?

Answer 10

causes production loss
difficult to control due to wildlife reservoirs
human to cattle infection possible

Question 11

Why are the cases of Bovine tuberculosis low in the US compared to earlier times?

Answer 11

eradication programs

Question 12

Is bovine tuberculosis zoonotic?

Answer 12

yes

Question 13

How is Bovine tuberculosis transmitted?

Answer 13

through aerosols, ingesting contaminated milk

Question 14

what are the wildlife reservoirs for bovine tuberculosis?

Answer 14

badgers, deer, elk, feral pigs

Question 15

Describe the pathogenesis of Bovine tuberculosis

Answer 15

Question 16

what happens when Mycobacterium bovis is taken up by alveolar macrophages vs dendritic cells? (end result)

Answer 16

alveolar macrophages - granuloma formation, bacteria contained
dendritic cells - lymphatic tuberculosis

Question 17

Which mycobacterium species can spread from humans to dogs?

Answer 17

Mycobacterium tuberculosis

Question 18

What causes the necrotic and caseous lesions seen with bovine tuberculosis?

Answer 18

lytic enzymes released by activated macrophages

Question 19

Explained how Bovine tuberculosis that is cleared or latent can be reactivated

Answer 19

granulomas contain infection > no signs of disease > bacteria survive inside granuloma > bacteria reemerge and cause disease

Question 20

what are granulomas in tuberculosis called?

Answer 20

tubercles

Question 21

what are the arrows pointing at on these animals?

Answer 21

tubercles

Question 22

When are the clinical signs seen with bovine tuberculosis?

Answer 22

only evident in advanced disease

Question 23

what are the symptoms of advanced pulmonary tuberculosis?

Answer 23

cough, fever

Question 24

what are the symptoms seen when tuberculosis is spread via blood or lymphatics? How is the advantageous transmission?

Answer 24

tuberculosis mastitis > facilitated spread of infection to calves

Question 25

How is bovine tuberculosis diagnosed?

Answer 25

tuberculin skin test blood-based test Isolation for M. bovis

Question 26

Describe the tuberculin skin test (hypersensitivity and preparation)

Answer 26

delayed-type hypersensitivity purified protein derivative is prepared from mycobacteria

Question 27

what is a positive tuberculin skin test?

Answer 27

hard swelling at injection site

Question 28

what are the two types of tuberculin skin test?

Answer 28

single intradermal (caudal fold) test Comparative cervical test

Question 29

what test is this?

Answer 29

single intradermal (caudal fold) tuberculin skin test

Question 30

what test is this?

Answer 30

comparative cervical tuberculin skin test

Question 31

Which tuberculin skin test can have a false positive results? How?

Answer 31

Single intradermal (caudal fold) test animals sensitized to mycobacteria other than M. bovis

Question 32

when do false negatives occur with tuberculin skin tests?

Answer 32

immunosuppresion - stress, early post partum, drugs

Question 33

what are the two blood-based tests to diagnose bovine tuberculosis?

Answer 33

IGRA and ELISA

Question 34

what medium is used to isolate M. bovis? How long does it take to grow?

Answer 34

Lowenstein-Jensen medium 8 weeks

Question 35

which tuberculin skin test would you want to use for a herd of cattle that lives on a ranch with poultry?

Answer 35

Comparative cervical test

Question 36

what is the control in the comparative cervical test?

Answer 36

M. avium

Question 37

How is Bovine tuberculosis treated?

Answer 37

treatment not part of control programs > slaughter of reactors and disinfection of farm buildings

Question 38

what is the causative agent of Johne's disease?

Answer 38

M. avium subsp. paratuberculosis (MAP)

Question 39

what is Johne's disease also called?

Answer 39

Paratuberculosis or MAP infection

Question 40

Select one term in each pair for Johne's disease acute/chronic environmental/contagious treatable/fatal

Answer 40

chronic, contagious, invariably fatal enteritis

Question 41

what animals are most susceptible to MAP infection?

Answer 41

newborn animals

Question 42

how are calves infected with MAP?

Answer 42

accidental ingestion of feces

Question 43

How are infections with MAP recorded in cattle?

Answer 43

milk and colostrum

Question 44

What is the pathogeneis of Johne's disease?

Answer 44

bacteria attach M cells > taken up by macrophages > survive within macrophages by preventing phagosome-lysosome fusion > granuloma formation >thickened and corrugated intestine > malabsorption and diarrhea

Question 45

what is the causative agent?

Answer 45

Mycobacterium avium subsp. paratuberculosis

Question 46

what are the main clinical symptoms of Johne's disease in cattle?

Answer 46

diarrhea, SI and LI thickened and corrugated

Question 47

what are the main clinical symptoms of Johne's disease in sheep and goats?

Answer 47

chronic weight loss

Question 48

what are the main clinical symptoms of Johne's disease in deer?

Answer 48

diarrhea, rapid weight loss

Question 49

How is Johne's disease diagnosed through fecal culture? How long does it take?

Answer 49

Herrold's egg yolk medium 8-12w

Question 50

what is a rapid radiological method to measure growth of MAP?

Answer 50

BACTEC

Question 51

what is a field test that can be done to detect Johne's disease?

Answer 51

Johnin PPD or IGRA

Question 52

what is the post-mortem way of diagnosing Johne's disease?

Answer 52

necropsy

Question 53

How is Johne's disease controlled?

Answer 53

isolate animals with MAP signs confirmed animals cull

Question 54

Since detection and elimination of subclinical infection with Johne’s is difficult how should it be monitored?

Answer 54

PCR or culture of feces

Question 55

What should you suggest to herds that have had repeat cases of MAP?

Answer 55

proper hygiene/husbandry

Question 56

Is there a vaccine for Johne's disease?

Answer 56

no but vaccine trials are showing promising results - in the making

Question 57

what is the causative agent of poultry tuberculosis?

Answer 57

Mycobacterium avium subsp. avium