Anthrax
the “agent of doom”
By Molly McMahon and
Katelynn Johnson
Basic Info
• Anthrax is an acute disease in animals caused
by the bacteria Bacillus Anthracis.
• Anthrax bacillus has the unique ability to form
long-lived spores, they become inactive
dormat spores and can remain this way for
many decades maybe even centuries! This
can be caused by:
• The death of a host
• Extremes in temperature
Basic Info
• Anthrax is found on all of the continents
except Antarctica.
• It most commonly infects wild and
domesticate herbivorous mammals
• Usually the mammals become infected
by inhaling the bacteria while eating
Infection
• Ingestion is assumed to be the most common
way animals are infected, however it is yet to
be proven.
• Carnivores are infected by feeding on infected
animals.
• Anthrax can infect humans by being exposed
to infected blood or tissues, eat tissues of an
infected organism, or are exposed to high
densities of anthrax spores.
Forms of Infection
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Cutaneous anthrax
Bacteria enters through cut or abrasion
Contact with affected animals
Easily treatable through antibiotics
Symptoms:
• Raised bump
• Painless ulcer with a necrotic (cell death) center
• Swollen lymph nodes locally
Forms of Infection
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Gastointestinal Anthrax
Infected meat is ingested
Mortality rate 25-60%
Symptoms
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Loss of appetite
Nausea
Abdominal pain
Vomiting of blood
Severe diarrhea
Forms of Infection
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Inhalation Anthrax
Begins in lungs
Incubation time of 7 days
Mortality rate of 100% with 1-2 days of
symptoms
Symptoms:
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Unremarkable upper-respiratory infection
Dyspnea (uncomftorable breathing) , diaphoresis
(perspiring profusely), myalgia (muscle pain)
Septic shock
Infection
• Anthrax does not spread directly from one
infected organism to another, it’s the spores
that are transferred from one organism to
another.
• There are 89 known strains of anthrax
documented in the world today.
• The most widely recognized is the Ames
strain. It was the strain used in the 2001
Athrax attacks on the US.
Infection
• Once the spores are inhaled they are
transported through the air passages of the
body, and into the lungs. Macrophages pick
up the spores and transport them to the
lymph nodes.
• Here the bacilli and spores cause damage to
the lymph nodes and cause chest pain and
difficulty breathing.
• The spores germinate into active bacilli and
burst the macrophages, multiplying and and
infecting the body with more bacilli which are
carried in the blood to the entire body.
How anthrax infects
Infection
• To enter the cells the lethal factors use
another protein produced by B.
anthracis, protective antigen. Edema
factor inactivates a type of phagocytic
cell so that they lose the ability to
phagocytose bacteria, meaning that it
cannot destroy the matter
Infection
• Recent evidence indicates that anthrax
targets endothelial cells and cause
vascular leakage of fluid and cells in the
body. This leads to hypovolemic shock
which is basically low blood volume and
septic shock.
Infection
Infection
• The severity of a strain of Anthrax
depends on many factors, however the
poly-D-glutamic acid capsule that
protects the bacterium from
phagocytosis by the specific host cell
and its toxins are a primary factor.
Anthrax & Biological Warfare
• The Ames strain was used in the 2001
Anthrax attacks on the US in a series of
mailed letters.
• The Vollum strain was isolated in 1935,
developed as a biological weapon for WWII,
it was never used.
• The Vollum strain was also used during the
Gruinard bioweapons trials.
• The Vollum 1B strain was used during the
1960’s in US and UK bioweapon programs.
Anthrax & Biological Warfare
• 220 pounds of powdered anthrax
material, seeded into the air of a city,
could kill more than 1 million people.
• In contrast, 80,000 would die in the
explosion of a 12.5-kiloton atomic
bomb.
Why Anthrax?
• It is easily grown
• Easy to spread when spores are
‘healthy’
• High Mortality
• Stores for long periods of time
• Non-transmissible
• Does not need ‘food’ to stay alive and
reproduce
Replication
• Plasmid pXO1 is involved in the growth of
B.anthracis
• Anthrax spores enter the body through
macrophages and are transported via the
lymphatic system to the lymph nodes where
germination occurs
• As replication occurs the anthrax organisms
release distinct toxins causing tissue edema,
hemorrhage, and host cell death
Factor proteins of Anthrax
• Lethal Factor (LF):
• Adheres to enzymes important to cell division
• Stimulates macrophages and causes inflammation, which is
normally a protective mechanism. But the LF enzyme is so active
that the hormone and inflammation become lethal to the cells.
• Edema Factor (EF):
• Leads to water unbalance, diarrhea, pneumonia, swelling
• This enzyme stimulates production of a normal cellular hormone, so
much so that the hormone levels immobilize the cellular immune
system. The cell becomes defenseless.
• Protective Antigen (PA):
• Promotes endocytosis (cell drinking) of itself
• Escape route from the endosome
Reproduction
• Anthrax reproduces asexually
• While this is not rare, the spores that
anthrax produces are “super”
• This means that the have an extremely
thick outer wall which allows it to
survive in many different kinds of
environments
More on factor proteins
• Neither the Edema factor protein or the
Lethal Factor protein can enter cells without
Protective Antigen
• Alone, the Protective Antigen is not harmful
• The lysis of macrophages and other cells
leads to release of:
• Pro-inflammatory mediators
• Reactive O2 and N2 species
• Lysomal enzymes which can attempt to protect the cell
• Anthrax proteins inhibit cell replication
Treatment
• The first effective vaccine that was developed
for anthrax was developed in 1881 by French
scientist Louis Pasteur.
• Australia, New Zealand, Russia, Europe,
North American and parts of Africa and Asia
have all contributed to more than 100 years
of animal vaccination programs.
• These programs have made Anthax a very
rare disease in animals with only a few dozen
cases reported each year.
Side Effects of Vaccine
• 30% report minor reactions: soreness,
redness, itching, swelling and lumps at the
injection site
• 35% experience muscle or joint aches, chills,
fever, headaches, nausea, loss of appetite,
feeling on unease
• Serious reactions requiring hospitalization are
rare, occurring about once per 50,000 doses.
• Severe allergic reactions can occur after any
vaccination less than one per 100,000 doses
Antibiotics
• Most antibiotics are effective against
B.anthracis:
• Doxycycline
• Penicillin
• Amoxicillin
• If inhaled or ingested, medications
through an IV reach the bacteria quickly
• Treatment can last for up to 60 days