Anthrax and plague Flashcards

1
Q

devastating disease of livestock?

A

anthrax

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2
Q

what organism causes anthrax?

A

bacillus anthracis

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3
Q

bacillus anthracis vs bacillus cereus?

A

anthracis –> anthrax cereus –> food poisoning

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4
Q

bacillus vs clostridia

A

both are gram + spore forming rods but bacillus are aerobic or facultatively anaerobic and clostridia are strict anaerobes

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5
Q
A

bacillus anthracis

gram + rods forming long filaments

“box car” organisms

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6
Q

virulence factors of bacillus anthracis

A

capsule of poly D-glutamic acid

and

toxins = edema toxin (EF + PA) and lethal toxin (LF + PA)

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7
Q

what is PA?

A

protective antigen

it is the B subunit (cell-binding component) for both toxins of anthrax

–translocates EF and LF into the cell

***none of the 3 components is toxic on its own

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8
Q

how does anti-PA antiboody work?

A

it neutralizes both toxins of anthrax because PA is the B subunit (cell binding component) of both toxins

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9
Q

EF

A

edema fector

a calmodulin-dependent bacterial adenylate cyclase

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10
Q

LF

A

lethal factor

a zinc metalloprotease that cleaves mitogen-activated protein kinase kinase (MAPKK) and inhibits the MAPK signal transduction pathway in macrophages

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11
Q

reservoir and transmission of bacillus anthracis

A
  • Reservoir: Soil –> Herbivores infected during grazing
  • Transmission to humans

—–Contact with infected animals, hides, hair, wool, bone, bone products; biting flies

—–Ingestion of contaminated meat

—–Inhalation-industrial settings, intentional use

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12
Q

3 forms of anthrax

A

cutaneous

GI

inhalational (woolsorters disease and bioterrorism)

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13
Q

cutaneous anthrax

A

malignant pustule/most common form

  • Occupational exposure to animals/heroin users
  • Papule progresses to central necrosis to black eschar

–Painless

–Edema

–80-90% complete resolution

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14
Q

GI anthrax

A
  • RARE
  • Follows ingestion of spore-contaminated meat
  • Ulcers form at site of invasion (e.g., mouth, esophagus, intestine) which leads to regional lymphadenopathy, edema, and sepsis
  • Mortality greater than 50%
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15
Q

inhalational anthrax

A
  • Incubation period 1-43 days (dose dependent)
  • Non-specific symptoms 3-5 days
  • Terminal phase

–Dyspnea, stridor, cyanosis, increased chest pain, chest wall edema, followed by shock and death within 24-36 hours (45-90%mortality)

–Hemorrhagic mediastinitis, hemorrhagic pleural effusions

•can present with Meningitis and/or GI hemorrhage

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16
Q

what do you see on xray of inhalatinal anthrax?

gram stain of blood?

A
  • Chest x-ray is often pathognomonic: widened mediastinum with pleural effusions, without infiltrates.
  • Late in the course, Gram stain of blood may reveal broad Gram-positive rods.
17
Q
A

bacillus anthracis

18
Q

treatment for inhalational and cutaneous anthrax

A

ciprifloxacin or doxycycline

+

clindamycin

+

rifampin

19
Q

anthrax vaccine (biothrax)

A

inactivated vaccine of attenuated, non-encapsulated strain primarily of PA with traces of LF and EF

20
Q

agent that causes the bubonic plague?

A

yersinia pestis

21
Q

description of yersinia pestis?

transmission?

A

gram - rod; grows well on macconkeys agar

flea vector required for transmission (exception: pneumonic plague)

occurs naturally in the western US/southwestern states, cycling amongst rodents

22
Q

plague in humans

A

humans and domestic animals are bitten by fleas from dead animals are at risk for contracting plague

cats can directly infect humans by coughing infectious droplets into the air

dogs less likely to be ill but can still bring home the fleas

in addition to flea bites, people can be exposed by handling skins or flesh of infected animals

23
Q

plague due to yersinia pestis

pathogenesis and progression

A
24
Q

mechanism for anthrax toxin

A
25
Q

acral gangrene or axillary bulba

A

yersinia pestis

“plague”

26
Q

lab diagnosis of plague

A

culture on MacConkey’s/sheep blood agar for 5 to 7 days.

—Gram stain reveals polymorphonuclear leukocytes and plump gram-negative coccobacilli

—With Wayson staining, Y. pestis appears as light blue bacilli with dark blue polar bodies

27
Q

mediastinitis indicates….

A

Bacillus anthracis

28
Q

safety pin appearing gram - rods?

A

yersinia pestis