Anthrax
The Biology in the
Bioweapon
生化武器：炭疽
By Raphaella So
蘇韋霖
It
was seven days after 9/11 when the
envelopes containing inhalational anthrax were
first mailed out. Victims experienced symptoms
similar to that of a common flu before the
impact escalated into difficulty in breathing,
high fever, and even death. From October to
November 2001, officials reported a total of 22
cases of anthrax infection, 5 of which were fatal
[1]. It was a bioterrorist attack.
While anthrax may appear to be a modern-
day threat, it has, in fact, been described
in scholarly writings in Ancient Greece and
Rome. “Anthrax” refers to a bacterial infection
by
Bacillus anthracis
. The first clinical trial of
anthrax was per formed in the 18
th
centur y.
By the late 19
th
century, Robert Koch made a
historical breakthrough in the study not only
of anthrax but also in medicine. After isolating
the bacteria and growing it in a culture, he
was able to show that the diseases in animals
manifest directly in response to the injection of
specific microorganisms. His experiments also
developed an understanding of the growth of
B.
anthracis
, leading to the first use of anthrax as
a biological weapon in the early 20
th
century.
One famous example of bioterrorism involving
the disease is Japan’s attack on Manchuria
during World War II.
B. anthraci s
lays dormant on soi l in its
endospore form, resistant to extreme conditions
such as heat, acidity, alkalinity, humidity, or
even γ radiation. With its exceptional resilience,
it can survive for decades on certain soil types.
The lethality and ability for
B. anthracis
to
survive in hostile environments are attributed to
the protein products of its virulence plasmids.
One plasmid codes for proteins that disrupt
major signaling pathways - in this case, lethal
facto r and protect i ve ant i gen. Anothe r
virulence plasmid codes for a capsule that
protects the bacteria from phagocytosis by the
host’s immune system.
Given the bacterial association with soil,
anthrax under standably or iginated as an
agricultural disease infecting grazing animals
such as cows and sheep. The most common
non-deliberate human infections thus occur in
patients who have routine contact with farm
animals or produce. Endospores of B. anthracis
enter the human body through ingestion, open
wounds, and inhalation.
