Anthrax

Question 1

What is Anthrax?

Answer 1

Gram-positive bacterium,* Bacillus anthracis*

Question 2

What are the two forms of Bacillus anthracis?

Answer 2

1. Vegetative (non-motile rods, fragile)
2. Spore (ovoid, long-lasting)

Question 3

What are the requirements for sporulation of Bacillus anthracis?

Answer 3

1. Oxygen
2. Poor nutrient condition (eg outside host)

Question 4

Can you perform an autopsy/post mortem on an animal that was infected with anthrax?

Answer 4

NO! The bacteria would sporulate.

Question 5

What are the 3 main routes to anthrax infection?

Answer 5

1. Cutaneous (skin abrasions)
2. Gastrointestinal (contaminated food/soil)
3. Oropharyngeal (aerosolized spores)

Question 6

Of tthe 3 main routes to infection, which 2 routes can be lethal if untreated?

Answer 6

Gastrointestinal and Oropharyngeal

Question 7

Anthrax can affect all mammals and birds, but what group of animals is especially at risk?

Answer 7

Ruminants

Question 8

What are the 3 forms of systemic anthrax disease?

Answer 8

1. Peracute
2. Acute
3. Subacute

Question 9

Peracute/Acute Anthrax Infections primarily affects…?

Answer 9

Ruminants and horses

Question 10

What are the symptoms of peracute/acute anthrax infection?

Answer 10

1. Tremors
2. Neck edema
   
   1. Dyspnea
   2. Asphyxiation
3. Abortion
4. Bloody discharge

Question 11

Subacute infection can affect all mammals, but especially… ?

Answer 11

pigs, cats, dogs

Question 12

Symptoms of Subacute Anthrax infection?

Answer 12

1. Neck edema
   
   1. Dyspnea
   2. Asphyxiation
2. Anorexia
3. ovmiting
4. Diarrhea
5. necrosis of GI tract

Question 13

The anthrax toxin is composed of what 3 proteins?

Answer 13

1. Protective Antigen (PA)
2. Lethal Factor (LF)
3. Edemic Factor (EF)

Question 14

True or False:

The anthrax toxin proteins are harmless individually.

Answer 14

True

Question 15

Which of the 3 proteins in the anthrax toxin is absolutely necessary for toxic effects?

Answer 15

Protective Antigen (PA)

Question 16

how does the anthrax toxin enter the cell?

Answer 16

Anthrax receptors (ANTXR1, ANTXR2) bind Protective Antigen (PA). PA then forms a heptamer with the anthrax receptors and binds LF and/or EF. This complex is then internalized into endosomes which will gradually become acidic. The acidic environment turns PA into a channel that releases EF and LF into the cytoplasm.

Question 17

Once released into the cytoplasm Edemic Factor (EF) does what?

Answer 17

1. Converts ATP into cAMP (requires Ca2+/calmodulin)
2. Increases leakiness of the endothelial barrier
3. Inhibits phagocytosis by inflammatory cells

Question 18

Once released into the cytoplasm Lethal Factor (LF) does what?

Answer 18

1. Protease activity cleaves protective MAPKKs
2. Induces apoptosis (especially cardiovasular system)

Question 19

What is the current treatment for anthrax?

Answer 19

Antibiotics (doxycycline, ciprofloxacin)

Question 20

What are some potential treatments for Anthrax?

Answer 20

1. Dominant negative PA protein (bind anthrax receptor but LF and EF can’t bind)
2. Soluble anthrax receptors to bind PA (won’t be internalized)
3. Anthrax receptor antgonists
4. Anti-PA, EF, and LF antibodies (cocktail)

Question 21

How is anthrax used as a bioweapon?

Answer 21

1. PA+LF, no EF
2. High expression
3. Dispersable aerosol
4. Delivery system