Anthrax and plague

Question 1

devastating disease of livestock?

Answer 1

anthrax

Question 2

what organism causes anthrax?

Answer 2

bacillus anthracis

Question 3

bacillus anthracis vs bacillus cereus?

Answer 3

anthracis –> anthrax cereus –> food poisoning

Question 4

bacillus vs clostridia

Answer 4

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

Question 5

Answer 5

bacillus anthracis

gram + rods forming long filaments

“box car” organisms

Question 6

virulence factors of bacillus anthracis

Answer 6

capsule of poly D-glutamic acid

and

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

Question 7

what is PA?

Answer 7

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

Question 8

how does anti-PA antiboody work?

Answer 8

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

Question 9

EF

Answer 9

edema fector

a calmodulin-dependent bacterial adenylate cyclase

Question 10

LF

Answer 10

lethal factor

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

Question 11

reservoir and transmission of bacillus anthracis

Answer 11

• 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

Question 12

3 forms of anthrax

Answer 12

cutaneous

GI

inhalational (woolsorters disease and bioterrorism)

Question 13

cutaneous anthrax

Answer 13

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

Question 14

GI anthrax

Answer 14

• 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%

Question 15

inhalational anthrax

Answer 15

• 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

Question 16

what do you see on xray of inhalatinal anthrax?

gram stain of blood?

Answer 16

• 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.

Question 17

Answer 17

bacillus anthracis

Question 18

treatment for inhalational and cutaneous anthrax

Answer 18

ciprifloxacin or doxycycline

+

clindamycin

+

rifampin

Question 19

anthrax vaccine (biothrax)

Answer 19

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

Question 20

agent that causes the bubonic plague?

Answer 20

yersinia pestis

Question 21

description of yersinia pestis?

transmission?

Answer 21

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

Question 22

plague in humans

Answer 22

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

Question 23

plague due to yersinia pestis

pathogenesis and progression

Answer 23

Question 24

mechanism for anthrax toxin

Answer 24

Question 25

acral gangrene or axillary bulba

Answer 25

yersinia pestis

“plague”

Question 26

lab diagnosis of plague

Answer 26

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

Question 27

mediastinitis indicates….

Answer 27

Bacillus anthracis

Question 28

safety pin appearing gram - rods?

Answer 28

yersinia pestis