AnthraxIntroduction: Anthrax
is caused by a bacillus, called Bacillus anthracis, which is extremely infectious
for live stock such as cattle, horses, sheep and goats. It has gained a lot of
publicity in 2001 when in the US envelops had been mailed with anthrax spores.
The reason anthrax is so dangerous is that it is deadly once the spores get into
the body as it can grow anaerobically (without oxygen) in the depth of any tissue
and it also forms spores as a storage form that live in the soil for decades. Once
an animal has been infected in a herd, the decomposed body's bacilli will be transformed
into spores the moment the carcass has dried up. The healthy animals just need
a small cut in a hoof or elsewhere in the skin and the spores can enter the body
and become live bacilli again. In the U.S. herds are cared for by veterinarians
and animals are vaccinated with a live non virulent animal vaccine. This way
the environment is safer as not as many spores are around. However, there are
certain high risk occupations such as woolsorters of imported sheep or goat hair,
veterinarians and laboratory technicians who are more likely to be exposed to
anthrax bacilli (Ref. 1, p. 1158). Signs and symptoms:
There are three major symptom complexes, namely from skin exposure, from exposure
to the lung tissue (by inhalation) and from exposure to the gastrointestinal tract
(from swallowing spores). Skin symptoms: Even
though anthrax in man is rare, once it does occur the most common form of it is
from skin exposure where even some microscopically small skin abrasion can allow
some Bacillus anthracis spores to enter the system. This will within 3 to 5 days
lead to an itchy, but painless localized skin elevation with a reddish/brown color.
This grows ring-like in the periphery, but flattens in the center, where
it leads to ulceration, leakage of serum and eventually to formation of a black
crust. This can be seen in this picture
of anthrax. The next phase is further spread centrally with lymph
gland swelling and distribution and absorption of a toxin produced by the invading
Bacillus anthracis. The patient will complain of headaches, muscle aches and pains,
sick feeling to the stomach and vomiting. When the bacillus enters into the blood
stream the patient gets comatose due to a developing shock and dies. This deterioration
occurs mostly very fast within a matter of a few days. Lung
symptoms: If anthrax spores are inhaled the patient develops a flu
like symptoms over a few days with a cough and fever, but then there is an acute
deterioration. The fever increases, the cough worsens acutely to the point where
respiratory distress brings the patient to the hospital. The skin color is bluish
(=cyanosis), the patient looks deadly sick and gets into a coma and shock. Inside
the body the Bacillus anthracis has infected the lung tissue, has eaten itself
into the draining lymph glands in the space behind the chest bone (=mediastinal
lymph glands) and produces lots of toxin, which is very noxious to any tissue.
The end result is a necrotizing lymphadenitis, where the lymphatic tissue
gets liquefied and blood vessels get destroyed thus leading to internal bleeding
and release of toxic substances into the blood stream. The end result is more
distribution of the toxin into the whole body, more bleeding into all the vital
organs, fluid loss from the vascular system and lack of oxygen in tissues, shock
and death. This last deterioration can happen within a matter of hours or perhaps
up to 1or 2 days. Gastrointestinal symptoms:
If the mode of infection is via the gastrointestinal tract, there might be symptoms
initially reminiscent of a stomach flu with nausea and vomiting. However, very
quickly the patient will deteriorate, vomit blood or coffee grounds material (this
is blood modified by stomach acid), and have excruciating abdominal pain. The
invading Bacillus anthracis is eating its way from a surface erosion in the stomach
or in the small intestine into the mesenteric lymph glands that drain the gastrointestinal
region, which leads to a necrotizing lymphadenitis similar as described above.
The patient deteriorates very quickly as the toxins go right to the liver, the
major metabolic organ, and into the blood stream. Sepsis with Gram negative bacteria
(E.coli) ensues, and the patient dies in a coma within only a few days of turning
sick. Diagnostic tests: If the physician thinks
that there would be a possibility of anthrax, treatment will be initiated before
tests for it are even done to ensure that no time is wasted. For, if anthrax is
confirmed later, every minute of stopping the toxin from being produced by the
bacillus counts and may save a patient's life. Cultures are taken from the possible
portal of entry such as the infected skin area. This is more difficult in the
case of lung or gastrointestinal anthrax, but endoscopic methods (bronchoscopy,
gastroscopy) can be utilized to visually diagnose the condition and to get samples
for culturing. Throat swabs, samples of vomitus and phlegm samples can all be
cultured. If there is no obvious infected lesion with lots of organisms to culture,
then tissue samples can be injected into laboratory mice that are sacrificed later
to obtain a positive or a negative result. This is a very sensitive and specific
test. Treatment:95%
of all cases in the U.S. are the skin type (=cutaneous type). As there is a certain
incubation time where the local infection can be treated, there is an excellent
prognosis when treated promptly with antibiotics such as high dose penicillin
G injection or treatment with doxycycline or ciprofloxacin orally (Ref. 2). Unfortunately,
the 5% of other forms of anthrax in the U.S. (gastrointestinal, pulmonary or meningeal
anthrax) have a very high mortality rate as the patient is battling the systemic
effect of a toxic shock-like condition. These cases need to be treated
in an Intensive Care Unit setting with Swan-Ganz catheters in place, with large
bore intravenous lines and the fluid balance has to be measured carefully while
a combination of intravenous antibiotics are given as well, combined with corticosteroids
to mitigate the toxic reactions of the body to the Bacillus anthracis. It is more
important for the long term success to know that the time between the ingestion
or inhalation of the spores of Bacillus anthracis to the beginning of the therapy
was short than it is to know exactly what antibiotics and other treatment modalities
were used in the treatment. Skin lesions of the head and neck have to be treated
with intravenous antibiotics as well as the complication rates of these lesions
is potentially higher. Usually the patients are treated with antibiotics 7 days
beyond he point where they have clinically recovered, just in case. Prevention:
An effective anthrax vaccine for humans exists and has been in use for
several years by military personal. It consists of inactivated bacteria (passive
immunization) that is given by subcutaneous injection (like a flu injection).
Despite many irrational fears this vaccine has been found to be very effective
and without many side-effects. Ref. 3 lists as side-effects some local irritation
at the site of the injection, a few minor headaches, a mild fever and fatigue.
These symptoms were only transitory and this has to be related to the knowledge
that the person is now protected against anthrax. Health care personnel working
in emergency rooms, soldiers, veterinarians, woolsorters and laboratory technicians
should be vaccinated with this vaccine and occasional booster vaccinations need
to be given to maintain antibody titers.
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