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ANTHRAX:
Anthrax is considered a leading potential agent in bioterrorism or
biowarfare and, as such, could present in epidemiological unusual
circumstance
It is highly lethal.
Deadliest chemical warfare 100 million lethal doses per gram of anthrax
material (100,000 times deadlier than the agent).
Silent, invisible killer.
Inhalational anthrax is virtually always fatal.
There are low barriers to production.
Low cost of producing the anthrax material.
Not high technology. Knowledge is widely available.
Easy to produce in large quantities.
It is easy to weaponize.
It is extremely stable. It can be stored almost indefinitely as a dry
powder.
It can be loaded, in a freeze-dried condition, in munitions or
disseminated as an aerosol with crude sprayers.
Currently, we have a limited detection capability.
WHAT IS ANTHRAX
INTODUCTION:
THE anthrax bacillus, Bacillus anthracis, was the first bacterium shown to
be the cause of a disease. In 1877, Robert Koch grew the organism in pure
culture, demonstrated its ability to form endospores, and produced
experimental anthrax by injecting it to animals.
Bacillus anthrax is a very large, GRAM positive, spore forming rod, , which
ca 1-1.2um in width x 3 5um in length. The bacterium can be cultivated in
ordinary nutrient medium under aerobic or anaerobic conditions.
A microscopic picture of spores and vegetative cells of bacillus anthrax,
which cause the disease anthrax.
Bacillus anthracis. Gram stain. The cells have characteristic
squared ends. The endospores are ellipsoidal shaped and located
centrally in the sporangium. The spores are highly refractile to
light and resistant to staining.
Anthrax naturally infects many species of grazing mammals such as sheep,
cattle and goats, which are infected through ingestion of soil contaminated
by B. anthrax spores. There are three forms of human disease depending on
how infection is acquired: cutaneous, inhalation and ingestion. Over 95% of
cases the infection is cutaneous, acquired by inoculation of spores into
small abrasions of the skin, usually during handling of untreated animals
hides.
----------------------------------------
TRANSMISSION
Modes of transmission include:
1----- Cutaneous contact with spores, spore contaminated materials or
infected skin lesions. Infection requires an existing break in the skin.
Contact with tissue of animals dying of the disease; possibly by biting
flies that had partially fed on such animals.
2-----Inhalation of spores in risky industrial processes such as tanning
hides and processing wool or bones _ where aerosols of B.anthrax can be
produced.
3------Ingestion of contaminated meat. There is no evidence that milk
from infected animals transmits anthrax.
-----------------------------
INCUBATION PERIOD
1 day to 8 weeks depends on dose and exposure route.
. 1-7 days fallowing cutaneous exposure.
.1-6 days fallowing inhalation exposure.
.1-7 days fallowing ingestion.
PERIOD OF COMMUNICABILITY
. Transmission of anthrax infection from person to person is highly
unlikely.
. Contact with skin lesions can result in subsequent cutaneous
infection.
. Airborne transmission from person to person does not occur.
CLINICAL FEATURES
Human anthrax can occur in three forms;
Inhalation/ pulmonary
Cutaneous
Gastrointestinal
Clinicians should be aware of the possibility of cases on anthrax, in
any healthy patient with the fallowing clinical presentation as in now
days it can be expected in deliberate release of anthrax spores.
INHALATION/PULMONARY
. Non-specific prodrome of flu like illness fallowing inhalation of
spores with fever, headache, myalgia and non-productive cough. 2 to 4
days after initial symptoms there is abrupt onset of respiratory failure
and on chest x-ray a widened mediastinum is often present, suggestive of
mediastinal lymphadenopathy and hemorrhagic mediastinitis.
. Gram-positive bacilli seen in blood cultures, usually after 2-3 days
of onset of illness.
. Treatment may be successful in early stage but by the time of
respiratory or bacteraemic symptoms develop. Treatment may not arrest
the disease before a fatal outcome.
-----------------------------------------------------------
CUTANEOUS
. Local skin involvement after direct contact.
. Commonly seen on hands, forearms and head.
. 3 days after exposure a raised, itchy, inflamed pimple appears
fallowed by a papule that turns vesicular and then 2-6 days later a
black Escher develops. Extensive edema accompanies the lesion. The
swelling tends to be much greater than wound normally be expected for
the size of the lesion.
. Responds to oral antibiotics.
. Rarely may progress to bacteramia or meningitis without treatment.
GASRTRO-INTESTINAL
. Rare
. Characterized by severe abdominal pain, nausea and vomiting with
watery or bloody diarrheas.
.2 3 days after onset bacteramia may develop.
. Usually fatal if it progress to bacteramia.
MENINGITIS
Meningitis due to B. anthrax is a very rare complication that may result
from a primary infection elsewhere.
SIGNS AND TESTS
The appropriate tests to diagnose anthrax depend on the type of
disease suspected (cutaneous vs. inhalational vs. gastrointestinal).
If cutaneous anthrax is suspected, a culture of the skin lesion will
be done to identify the bacteria that cause anthrax.
If inhalational anthrax is suspected, a chest X-ray, blood cultures,
sputum cultures, spinal tap for CSF culture, and gram stain may be
performed.
TREATMENT
INHALATION AND INGESTION
-----------------------------------------------------------------------------------------
CUTANEOUS
Treatment should be initiated with oral ciprofloxacin 500mg twice daily
for 7 days. This can be changed to oral amoxycillin if the organism is
found to be sensitive. Treatment may need to be continued for up to 60
days if there is suspicion of deliberate release in order to provide
cover for inhalation anthrax, which may have been acquired concurrently.
INFECTION CONTROL PRACTICE
DECONTAMINATION OF EXPOSED PERSONS
IT may include.
. Removal of contaminated clothing and possessions it should be stored
in labeled double plastic bags until exposure to anthrax has been ruled
out.
. If anthrax is confirmed, all contaminated material must be incinerated
or autoclaved.
. Minimal handling of clothing and fomites to avoid agitation.
. Instructing exposed persons to shower thoroughly with soap and water.
. Instructing attending personnel to wear appropriate barrier
protection.
ISOLATION OF PATIENTS
. Standard Universal Precautions should be used for the care of patients
infected with anthrax- gloves, gowns and hand washing.
. Single room placement for anthrax patients is not necessary.
. Airborne transmission does not occur.
. Skin lesions may be infectious, but this requires direct skin contact.
Maintained when patient is moved.
CLEANING, DISINFECTION AND WASTE DISPOSAL
Contaminated environmental surfaces should be cleaned with 0.5%
hypochlorite solution.
POST-MORTEM
Post-mortem examination is encouraged when anthrax is suspected.
IF done then standard precautions should be used.
-------------------------------------------------------------------
PROPHYLATIC TREATMENT FOR
PERSONS EXPOSED TO ANTHRAX SPORES.
In the event of a known exposure to anthrax spores, antibiotic
prophylaxis should be initiated as soon as possible as described in
table
Prophylaxis should be continued until B. anthracis exposure has been
excluded. If exposure is confirmed, prophylaxis should continue for 60
days. During this period, no special precautions are required for
exposed persons, but they should receive an anthrax information sheet
and be instructed to get medical treatment in the event of any
suspicions symptoms.
CIPROFLOXACIN IS NOT LICENSED FOR USE IN CHILDREN OR PREGNANT WOMEN.
If B.anthrax exposure is confirmed, the organism must be tested for
Penicillin susceptibility. If susceptible, exposed persons may be
treated with oral amoxycillin as an alternative to ciprofloxacin or
doxycyclacin. However, pharmacokinetic studies have shown that
ciprofloxacin achieves far higher concentration in lungs macrophages as
compares to penicillin, and is there fore a more effective prophylactic
antibiotic.
IMMUNIZATION
In certain circumstances, in addition to antimicrobrial prophylaxis,
post exposure immunization may also be indicated. This consists of 5
doses of vaccines at 0, 3 and 6 weeks. Then at least 6 months and 1 year
after the exposure. With vaccination post exposure antibiotic
prophylaxis can be reduced to 4 weeks. Advice on the use of vaccine must
be obtained. Anthrax vaccines intended for animals should not be used in
humans.
Pregnant women should be vaccinated only if absolutely necessary.
Are there adverse reactions to the anthrax vaccine?
Mild local reactions occur in 30% of recipients and consist of slight
tenderness and redness at the injection site. Severe local reactions are
infrequent and consist of extensive swelling of the forearm in addition
to the local reaction. Systemic reactions occur in less than 0.2% of
recipients.
Some experts believe that anthrax vaccine is not useful for more detail
on this visit the following site http://www.clarionledger.com/news/0105/16/m11.html
http://www.gulfwarvets.com/anthrax.htm
Researchers Call Anthrax Vaccine Safe and Likely to Work - NY Times
http://www.fda.gov/ola/2000/anthraxvaccine.html
Visiting these sites will put u in doubt weather anthrax vaccine is
useful or not useful according to New York times and FDA anthrax vaccine
has been proven to be useful without side effects but according to the
other 2 sites on military personal who used this vaccine not only
complains side effects but also a women died of it
If some one I ask my advice I think antibiotic treatment is safer then
vaccination but vaccination can be used in very extreme conditions
because side effects are worth then human life and a lot of people
according to research didnt developed side effects.
CONTACT CASES
There is no need to provide antibiotic prophylaxis or immunization to
contacts of patients unless there is concern they were also exposed to
initial exposure.
ENVIRNOMENTAL DECONTAMINATION
The greatest risk to human health occurs after release of anthrax spores
during the period anthrax spores remains airborne, called primary
aerosalation
Expert advice will be provided to determine the time after release for
which spores are likely to remain airborne. Once they have settled,
although they remain infectious for long periods, the risk to human
health is much lower. Decontamination of small areas may be achieved
with 0.5% hypochlorite solution.
PROTECTION OF FRONTLINE WORKERS
This includes all emergency workers involved in management of the scene.
----------------------------------------------------
REFRENCES: -
The following online sites you can visit for my details and work on
anthrax.
http://www.fda.gov/cder/drug/infopage/penG_doxy/default.htm
http://www.freepint.com/gary/bioterror.html
http://news.bbc.co.uk/hi/english/health/newsid_1580000/1580930.stm
http://www.npr.org/news/specials/response/home_front/features/2001/oct/011010.anthrax.html
http://www.aomc.org/ComDiseases/Anthrax.html
http://www.guardian.co.uk/anthrax/0,1520,575053,00.html
http://www.aviationmedicine.com/anthrax.htm
http://www.chem.ox.ac.uk/anthrax/
http://www.bt.cdc.gov/Agent/Anthrax/Anthrax.asp
http://www.vetmed.lsu.edu/whocc/mp_world.htm
http://jama.ama-assn.org/issues/v281n18/ffull/jst80027.html
http://www.hhs.gov/news/press/2001pres/20011010a.html
http://www.anthrax.osd.mil/
http://www.cdc.gov/ncidod/dbmd/diseaseinfo/anthrax_g.htm
------------------------------
By:
Dr. Nusrat Shafiq
nusrat@itborn.com
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