ANTHRAX-What have we got to Worry about?.............Lot's..read for info...........
MIRVman
for everyone. Anthrax is a disease caused not by a virus, but rather by
bacteria. There aren't any known cases of anthrax passing from one
person to another, so it is considered to be noncontiguous.
It is still a large threat, however, because if it isn't recognized and
treated quickly enough it can be deadly. Bacillus anthraces is the
bacterium that causes the disease anthrax.
It has historically affected herbivores like cattle, sheep or other
grazing herds, but has also been a threat to humans who work with these
animals and their by-products.
While in the ground or on a surface, anthrax spores are relatively
harmless, but once they come into contact with the right environment
they begin to germinate.
They need an environment that is rich in amino acids, nucleosides and
glucose -- like those elements found in blood and other tissues in
humans or animals.
Once there, a series of changes takes place that can make these
bacteria deadly to its host.
In this monologue let's look at what anthrax is and how it affects
the body. We'll also discuss new research and ideas for treatment and
prevention of the anthrax disease.
Where Does it Come From?
Anthrax is found all over the world. It contaminates the ground when an
affected animal dies. It spreads when grazing animals pick it up from
contaminated dirt or through contaminated food sources such as bone
meal that may have been made from contaminated carcasses.
There appears to be an increase in the cases of anthrax among grazing
animals during droughts, when they tend to graze closer to the ground
and consume more dirt with the grass.
Anthrax may also spread when carnivorous animals, such as vultures or
even insects, feed on affected herbivores. The bacteria are then
transferred to other areas by the host and contaminate the ground when
that animal dies.
As the animal decays, the bacteria are exposed to oxygen and turn back
into the spores that contaminate the soil. The anthrax spores have a
very tough outer casing and can remain viable in the ground for
decades.
Many diagnostic laboratories around the world have anthrax samples for
use in research and for the identification of anthrax. Anthrax can be
grown in laboratories from these existing spores. In the wrong hands,
these spores can be grown, dried and milled for use in biological
weapons .
Inhalation into the lungs (inhalation anthrax) - The spores can be
inhaled in contaminated soil or other particles containing the spores.
The spores have no smell, taste or color, so a person would not notice
anything had happened unless the spores had been mixed into a substance
that could be readily seen, smelled or tasted.
In order to enter the lungs, where they can germinate, the spores have
to be very small -- from 1 to 5 microns (millionths of a meter).
According to an anthrax report published by the American Medical
Association, at least 2,500 spores have to be inhaled to cause an
infection
Entry into a cut or opening in the skin (cutaneous or skin anthrax) -
Open cuts and scrapes can allow entry of the spores into the body to an
environment in which they can germinate. This type of anthrax may also
be spread by biting insects that have fed on infected hosts.
The head, arms and hands are most often affected. People who handle
contaminated animal products such as leather, hair (particularly goat
hair) and wool are often exposed to the anthrax bacteria.
Cutaneous anthrax accounts for about 95 percent of cases worldwide. If
untreated, it has a fatality rate of five to 20 percent. If treated
with, antibiotics it rarely leads to death.
Entry through the gastrointestinal tract (gastrointestinal anthrax) -
Eating undercooked meat that is infected with the anthrax bacteria, or
drinking unchlorinated water that harbors the spores, can introduce the
bacteria into the gastrointestinal tract. Infection can occur in either
the upper or lower GI tract.
This form of anthrax is rare.
What Happens When it Enters the Body?
When viewed at the cellular level, an anthrax bacterium looks like a
jointed bamboo rod. When it enters the body and finds the environment
it needs, it moves to the lymph nodes.
From there it begins to multiply and produce a toxin that attacks
human cells resulting in hemorrhaging, swelling, a drop in blood
pressure and ultimately death.
The way it attacks the cells and exactly what it does was in question
for many years. Research that began in the mid 1980s has revealed some
interesting facts about the behavior of the anthrax bacterium when it
finds a host.
Researchers found that there are three proteins that are created by the
anthrax bacteria. These proteins are harmless individually, but
together can be deadly. These proteins are referred to as:
Protective antigen (PA)
Edema factor (EF)
Lethal factor (LF)
When these proteins are released, the protective antigen binds to the
cell surface and forms a type of channel in the cell membrane that
allows the edema factor and lethal factor to enter the cell.
The edema factor, when combined with the protective antigen, forms a
toxin known as the edema toxin. The lethal factor, when combined with
the protective antigen, forms a toxin known as the lethal toxin. It is
the lethal toxin that does the most damage within the cell.
Research in 1998, by George Vande Woude at the National Cancer
Institute in Frederick, MD, revealed clues to what the lethal toxin
does to the cells. He found that the lethal factor cuts enzymes in two
--
the enzymes that are responsible for transmitting signals within the
cells. He also identified the enzyme in question. He was studying the
mitogen-activated protein kinase (MAPK) pathway, which helps control
cell growth, embryonic development and the way oocytes (eggs) mature.
He was specifically looking for information about what the pathway
actually did in the oocyte maturation cycle, so he searched for
compounds that blocked the activity of the MAPK.
A database search lead him to the lethal factor.
It is still not completely understood why disrupting the signal
transmission within the cell results in the symptoms anthrax generates,
but research continues.
Research is also being done to find ways to alter the protective
antigen to disable its ability to allow the entry of the lethal and
edema toxins into cells.
The Symptoms of Anthrax
In its bacterial state, anthrax survives outside of a proper host
environment for only about 24 hours. But inside the body, where it gets
the nutrients it needs to grow, anthrax germinates and spreads rapidly.
Inhalation Anthrax
Inhaled anthrax typically begins showing symptoms in seven to 10 days,
although it could be as early as two to three days. It can take as long
as 60 days after exposure to the anthrax spores for the disease to
surface, however, and once the germination begins, the disease
progresses very rapidly. It appears to come in two stages:
It begins with fever, cough, headache, vomiting, chills, weakness,
abdominal pain, shortness of breath and chest pain. This first stage
may last from a few hours to a few days. Then there may be a brief
break in symptoms.
The second stage of the disease lasts anywhere from two to four days.
The symptoms for the second stage include fever, difficulty breathing,
sweating, a bluish discoloration of the skin, shock, and finally death.
Cutaneous Anthrax
Cutaneous anthrax, which occurs when the anthrax spore is deposited
into a break in the skin, may occur as late as 12 days after exposure.
The germination of the bacteria results in local swelling of the skin
-- a small papule (bump) will appear.
The following day the bump will enlarge into an ulcer and begin
discharging a clear fluid. Then, a painless, depressed black scab will
form that will dry and fall off within one to two weeks.
Treatment with antibiotics may not change the appearance or formation
of the bumps, but they decrease the chances that the disease will
become systemic.
Gastrointestinal Anthrax
The gastrointestinal form of anthrax, which occurs from eating or
drinking infected meats or water, brings about symptoms that include
nausea, vomiting blood, abdominal pain, bloody diarrhea, and weakness.
Death occurs in 25 to 60 percent of these cases.
Diagnosis and Treatment
According to an article in the Journal of the American Medical
Association, a blood sample is taken from the patient and cultured for
six to 24 hours. At this point, a "Gram stain" can be done. The Gram
stain highlights the bacteria.
The Gram stain takes about 10 to 15 minutes and can identify whether
the bacteria come from the anthrax category. At that point, biochemical
testing can be done to find the specific anthrax bacteria, which takes
another 12 to 24 hours.
Usually, the specimens have to be sent to national reference
laboratories for comparison with stock anthrax samples.
Treatment
Anthrax is treated with the antibiotics penicillin, ciprofloxacin or
doxycylcine. The antibiotic most often used is ciprofloxacin, partly
because of rumors that the Soviet Union had developed a
penicillin-resistant form of anthrax for use in biological warfare. It
is also specifically recommended by the U.S. Food and Drug
Administration (FDA) for use in treating anthrax.
Treatment of inhaled anthrax has to start very early in the progression
of symptoms. If treatment is begun after the symptoms have progressed
too far, then the bacteria may be killed but the toxins remain in the
body.
Vaccine and Treatment Research
The vaccine that was developed in the 1950s (licensed in 1970), is
currently only given to military personnel, people who work directly
with anthrax in research labs, and those who work with animals and
animal by-products that may be infected with anthrax.
The vaccine uses the anthrax protective antigen to make the body create
immunity to the disease. It is created from a strain of anthrax that
does not cause the disease, and doesn't use any live or dead whole
bacteria. There is a separate vaccine for use in animals. (That vaccine
can't be used in humans.)
The side effects of the anthrax vaccine include:
Mild local reactions at the site of the injection (like with many other
vaccinations)
Occasional, moderate local reactions that include redness, swelling and
tenderness, often at the site of the injection and extending up to 5
inches (13 cm) across the area
Large local reactions larger than 5 inches, including swelling of the
forearm and at the injection site
Muscle aches, joint aches, headaches, rash, chills, fever, nausea, loss
of appetite, and weakness for a few days after the vaccination
(experienced in up to 35 percent of people who get the vaccine)
A severe allergic reaction (appears once in every 100,000 doses)
A severe reaction that requires hospitalization (appears once in every
200,000 doses)
Research
Studies by R. John Collier and his colleagues at the Harvard Medical
School have uncovered a possible therapy that can be used both as a
vaccine and as a treatment for anthrax after the fact (particularly
when antibiotics were not administered quickly enough).
This research was based on the previous findings by George Vande Woude
and others at the National Cancer Institute in Frederick, MD, that
identified the role of the protective antigen in allowing the lethal
factor and the edema factor to enter the cell and begin wreaking havoc.
Collier's research involved mutating the protective antigen to prevent
this transfer. Experiments have suggested that even a single protective
antigen mutant can disrupt the entire process. This treatment has
worked in rats exposed to anthrax, but it is still not known how long
after exposure the treatment could be given and still be effective in
stopping the disease.
Because mutant protective antigen also appears to bring about an immune
response (at least in rats), it has the potential to be a vaccine as
well as a treatment. If successful, this approach could also be used
for other diseases.