Plague, Tulaermia, Brucellosis

Question 1

yersinia pestis morphology and stain

Answer 1

gram negative rod

Question 2

yersinia pestis metabolism

Answer 2

aerobic or facultative aerobic

non lactose fermenter

Question 3

yersinia pestis bubonic transmission

Answer 3

bubonic-

transmission from flea to mammal.

flea acquires yersinia pestis after blood meal

multiplies in gut, obstructs gut.

regurgitates mass organisms during bite

in mammals, enters lymphatics and causes regional adenitis

Question 4

yersinia pestis primary pneumonic transmission

Answer 4

spread via respiratory droplets to cause primary pneumonia in a contact

can lead to secondary pneumonia

Question 5

urban plague

Answer 5

yersinia pestis

animal epidemis occur among urban rats

their fleas seek human hosts as rats die

causes bubonic plague initially, then pneumonic

Question 6

rural plague

Answer 6

epizootic and enzootic patterns in rodents and fleas

10 cases /year in southwest

acquired via- flea bite, hand contact w/ infected animal, including pests

Question 7

yersinia pestis pathogenesis

Answer 7

extracellular
antiphagocytic capsule (F1 antigen)
V and W antigens needed for survival w/in macrophages
antiphagocytic properties present only at mammalian temps and not flea temps

intracellular- persistence w/in mammalian monocytes

toxins- exotoxin, LPS

Question 8

clinical features of bubonic plague

Answer 8

fever, malaise and painful lymphadenopathy

flea bite

Question 9

clinical features of pneumonic plague

Answer 9

fever, cough, SOB

Question 10

clinical features of septicemic plague

Answer 10

no bubo. widespread dessemination via blod

flea bite

Question 11

complications d/t yersinia pestis

Answer 11

DIC, plague meningitis

Question 12

immunity and vaccine w/ yersinia pestis

Answer 12

Ab develops and is protective

inactivated vaccine protects against bubonic plague

Question 13

yersinia pestis diagnosis

Answer 13

bubo aspirate- gram stain and culture, confirmed by fluorescent Ab

blood culture- positive w/ high numbers of organisms

serology- 4x rise in Abs against F1 ag

Question 14

yersinia pestis treatment

Answer 14

10 days of tetracyclin, strepto, or chloramphenicol

Question 15

franciscella tularensis morphology and stain

Answer 15

unencapsulated pleomorphic gram neg

Question 16

franciscella tularensis metabolism

Answer 16

fastidious aerobic slow grower

requires cysteine, glucose on blood agar

cold tolerant

Question 17

franciscella tularensis infectious dose

Answer 17

5-10 organisms

Question 18

franciscella tularensis transmission

Answer 18

transmitted from animals or arthropods to humans

rabbits- hand contact or ingestion
arthropods- ticks, deer flies

can be transmitted via aerosolized droplets, bites, or handling

Question 19

franciscella tularensis pathogenesis

Answer 19

injected directly via tick bite

organisms cause skin lesions, enters lymphatics and produces lymphadenopathy

can produce bacteremia and granuloma formation in spleen and liver

survives in monocytes

endotoxin produces initial symptoms

Question 20

franciscella tularensis symptoms and syndromes

Answer 20

abrupt fever, chills, malaise

ulcerglandular syndrome- most common- skin ulcers and painful adenopathy (inguinal and axillary)

typhoidal- bacteremia,

pneumonia

Question 21

franciscella tularensis diagnosis

Answer 21

dangerous to culture

fluorescent Ab staining of node biopsy

serologic- 4x titer rise

Question 22

franciscella tularensis treatment

Answer 22

sterpto for 7-10 days

relapses occur d/t intracellular persistence

Question 23

brucella morphology

Answer 23

pleomorphic gram neg

Question 24

brucella metabolism

Answer 24

fastidious, slow growth, requires 10% CO2

Question 25

brucella etiology

Answer 25

b. abortus- cattle- contaminated milk or direct tissue contact
b. suis- swine- tissue contact, airbrone, slaughterhouse workers

b melitensis- goat/sheep- unpasteurized milk, goat cheese

b canis- dogs- urine from kenneled dogs

Question 26

brucella pathogenesis

Answer 26

causes infection abortions in cows, sheep, pigs, and goats

disease of liver and spleen and humans

organisms ingested by PMNs, multiplies in monocytes

forms granulomas in liver, kidney, spleen, and bone marrow

Question 27

brucella clinical features

Answer 27

systemic and non focal, fever of undetermined origin

chills, myalgia, headache, arthralgias

intracellular persistence causes prolonged symptoms and risk of relapse

complications- osteomyelitis and endocarditis

Question 28

brucella diagnosis

Answer 28

occupational history

blood culture after 21 day incubation period

serologic- 4x titer increase (cross rxn: tularemia, typhoid, cholcera vaccine,, brucella skin test)

bone marrow biopsy

Question 29

brucella treatment

Answer 29

doxycycline plus rifampin for 6 weeks