Professor Dave here, let’s talk about anthrax.
Anthrax is a disease that is most recently famous for being sent through the mail as
a biological weapon.
But what is it exactly?
Anthrax is an ancient disease, and many researchers believe we can trace it all the way back to
the year 700 BC in ancient Egypt.
Over the years, some of the greatest microbiologists have studied it, including Robert Koch, who
used it to develop his famous Koch Postulates.
In fact, it was the first bacterium ever shown to be the cause of a disease in 1876, and
Louis Pasteur made the first vaccine for anthrax.
The symptoms of anthrax depend on the type of infection, and the type of infection depends
on how anthrax enters the body.
The most common entry points are the lungs, the skin, and the gastrointestinal system,
but it can also be injected, though this type of infection is very rare.
All types of anthrax, if left untreated, have the potential to spread through the body and
cause severe illness or death.
Let’s briefly talk about the types of infections: Cutaneous anthrax, or anthrax of the skin,
is the most common form of anthrax infection.
Infection can begin one to seven days after exposure, appearing as small, painless bumps
called papules, that may or may not develop swelling or an ulcer with a black center.
Generally, cutaneous anthrax is thought to be the least dangerous of the types.
Inhalation anthrax is the deadliest form of anthrax, which can take up to two months or
more to begin to show symptoms.
Symptoms begin as nonspecific fever, shortness of breath, headache, abdominal pain, and chills,
and can escalate to a more serious fever and significant swelling of the lymph nodes.
Even though this form of anthrax is inhaled, symptoms rarely involve the pulmonary system.
Almost every case of inhalation anthrax progresses to shock and death within three days of initial
symptoms unless swift treatment is delivered.
Gastrointestinal anthrax is more rare in the U.S., and symptoms depend on which portion
of the intestinal tract is infected.
If the upper gastrointestinal tract is infected, an infected person might develop ulcers in
the esophagus or mouth.
If the infection occurs in the intestines, an infected person will experience vomiting
and nausea.
In both cases, disease develops rapidly, and is thought to have a mortality rate close
to 100%.
Anthrax is caused by the rod-shaped, gram-positive bacterium Bacillus anthracis.
This bacterium is found naturally in soil and produces spores, which are round, highly
durable cells that can lie dormant for years, even decades.
These spores can activate when they find themselves in favorable conditions, like, say, the body
of an animal or person, which is rich with water, sugar, and other nutrients.
Once active, these bacteria can multiply and spread throughout the body, causing severe
illness and death.
So how do they cause damage?
Once ingested, the spores become activated and the bacteria begin to reproduce and make
proteins.
Reproducing bacteria make three different proteins: One, protective antigen or PA.
Two, lethal factor or LF.
And three, edema factor, or EF.
These proteins then combine to form two different toxins.
When protective antigen and lethal factor combine, they form the lethal toxin, which
sounds pretty ominous.
When protective antigen and edema factor combine, they form edema toxin.
Together, these toxins cause a fluid buildup around the lungs that kills infected cells,
ultimately causing severe disease and death in the infected animal or human.
It turns out that anthrax is not contagious, meaning it’s not spread from person-to-person.
For the most part, anthrax is a disease of livestock that ingest spores in plants, soil,
or water.
Humans most commonly become infected when they handle infected animal products like
wool or leather, or inhale anthrax spores from infected animal products.
Humans can also get anthrax from eating undercooked meat of infected animals.
Time is of the essence for those with an anthrax infection.
Getting proper medical care as quickly as possible can make the difference between life
and death.
All types of anthrax can be treated with antibiotics, and some cases are treated with antitoxin.
Livestock vaccines can prevent outbreaks in animals, and there are several types of vaccines
for humans.
One type protects adults that routinely handle animals or animal products, and another has
been approved by the FDA for use after exposure.
Anthrax is most common in agricultural regions of Central and South America, central and
southwestern Asia, sub-Saharan Africa, southern and eastern Europe, and the Caribbean, so
viewers in those regions take particular caution.