Download Anthrax

Legislative Council Secretariat
FS10/02-03
FACT SHEET
Anthrax
1.
Background
1.1
On 10 June 2003, the Department of Health (DH) announced a fatal case
of anthrax infection involving a 2-year-old boy. He had sudden onset of fever and
anorexia on 27 May 2003. His condition deteriorated on 30 May 2003 with
abdominal pain, irritability, vomiting and shortness of breath. He was immediately
taken to a hospital where he was certified dead shortly afterwards. DH has been
investigating this case of anthrax.
1.2
This fact sheet aims to provide the Legislative Council Panel on Health
Services with some basic information about anthrax.
2.
Some basic information about anthrax
What is anthrax?
2.1
Anthrax is an acute infectious disease caused by the spore-forming
bacterium Bacillus anthracis. The disease most commonly occurs in animals and can
also infect humans. Anthrax spores may survive in the soil, water and on surfaces
for many years, and can only be destroyed by steam sterilization or burning.
How common is anthrax?
2.2
Anthrax is infrequent among industrialized regions. It is more common
in agricultural regions where anthrax in animals is common. When anthrax affects
humans, it is usually an occupational hazard of agriculture and wildlife workers who
handle infected animals.
2.3
Anthrax infection is rare in Hong Kong. There have been three other
cases reported in the past 20 years. The two cases in 1982 were occupationally
acquired cutaneous anthrax whereas the one in 1994 was a fatal sporadic case of
intestinal anthrax involving a 13-year-old boy.1 (Please see paragraph 2.6 below for
details of the three forms of anthrax.)
1
The boy died in October 1994 on the tenth day of his illness. A detailed epidemiological
investigation was carried out when the case was reported to DH. Undercooked contaminated
meat was suspected to be the source of infection, but it could not be confirmed since laboratory
investigations of food samples were negative for the anthrax bacilli. No further cases were
reported and family members of the boy were free from symptoms.
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FS10/02-03
How is anthrax transmitted?
2.4
Anthrax organisms can cause infection in the skin, gastrointestinal tract, or
the lungs. To do so, the organism must be rubbed into abraded skin, swallowed, or
inhaled as a fine, aerosolized mist.
Can anthrax spread from person to person?
2.5
Transmission from person to person is very rare. According to the
Centers for Disease Control and Prevention (CDC) of the United States of America
(US), the chance of coming into contact with the bacteria is very low.
What are the symptoms of anthrax?
2.6
Anthrax occurs mainly in three forms: cutaneous, inhalation and intestinal.
Symptoms vary depending on how the disease is contracted and usually occur within
a few hours to seven days after exposure.
(a) Cutaneous anthrax: Occurs when the bacterium enters skin wounds.
It begins as a raised itchy lesion and develops into a painless ulcer
with a black center. Lymph glands in the adjacent area may swell.
The disease is readily cured with appropriate treatment.
(b) Inhalation anthrax: Initial symptoms resemble a common cold.
After several days, severe breathing problems and shock may develop.
Inhalation anthrax without early treatment is usually fatal.
(c) Intestinal anthrax: Initial symptoms include nausea, loss of appetite,
vomiting, abdominal pain, fever, and severe diarrhoea. Intestinal
anthrax can be fatal without early treatment.
2.7
According to Anthrax Vaccine Immunization Program (AVIP) of the US,
anthrax spores are tasteless, odorless, and invisible, and early symptoms of inhaled
anthrax resemble the common cold or flu. Therefore, people may not know that they
are infected with anthrax in the early stage.
How can anthrax be treated?
2.8
Anthrax can be prevented after exposure to anthrax spores by early
treatment with the appropriate antibiotics given and supervised by a doctor. Early
antibiotic treatment of anthrax is considered to be essential as delay lessens chances
for survival. According to CDC, anthrax is susceptible to penicillin, doxycycline,
and fluoroquinolones, and an anthrax vaccine also can prevent infection. However,
CDC does not recommend vaccination against anthrax for the general public to
prevent the disease.
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FS10/02-03
What are the measures to prevent anthrax?
2.9
The public should observe the following measures to prevent anthrax:
(a) maintain good personal, food and environmental hygiene;
(b) wash hands properly before food handling; and
(c) thorough washing and cooking of food before consumption.
3.
Anthrax as a biological weapon
3.1
According to CDC, research on anthrax as a biological weapon began
more than 80 years ago. The Japanese cult Aum Shinrikyo attempted to release
anthrax in a Tokyo subway station in 1995, but the attacks failed to produce illness.
The accidental aerosolized release of anthrax spores from a military microbiology
facility in Sverdlovsk in the former Soviet Union in 1979 resulted in at least 79 cases
of anthrax infection and 68 deaths.
3.2
Anthrax powder was used in a series of letter attacks in the US, after the
September 11 terrorist attacks in New York and Washington DC. From 4 October to
2 November 2001, there were 10 confirmed cases of inhalation anthrax and 12
confirmed or suspected cases of cutaneous anthrax across the US. Investigation
indicated that the outbreak resulted from intentional delivery of Bacillus anthracis
spores through mailed letters or packages. The cases of cutaneous anthrax all
survived, whereas five out of the 11 people who contracted inhalation anthrax died.
3.3
For anthrax to be an effective agent in biological warfare, it must be
aerosolized into very small particles. This requires a great deal of technical skill and
special equipment. According to CDC, the manufacture of a lethal anthrax aerosol is
beyond the capacity of individuals or groups without access to advanced
biotechnology. However, autonomous groups with substantial funding and contacts
may be able to acquire the required materials. According to AVIP, the technology
needed to produce anthrax has legitimate uses in the biological and pharmaceutical
industries, and is available on the open market with few controls to purchase. Any
country with basic healthcare or a basic pharmaceutical industry has the expertise to
produce anthrax.
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FS10/02-03
3.4
Although inhalation anthrax is often cited as a potential biological weapon,
there are limitations to its use. Firstly, it is difficult to find strains of the bacteria that
will cause serious disease. Once such a strain is found, it is dangerous to handle and
sending the bacteria in letters does not make an effective biological weapon. Spores
of anthrax tend to clump together and fall to the ground, so they are not easily
breathed in. To be released as a weapon, the clumps of anthrax spores would have to
be ground down to a size that can be inhaled easily. Even after it is delivered, the
behaviour of the bacteria is somewhat unpredictable. It normally has an incubation
period of up to seven days, but could take up to 60 days to develop. Unlike other
potential biological weapons, such as smallpox or plague, anthrax cannot be
transmitted from person to person, thus it will not spread through a population after it
is released.
_________________
Prepared by Jackie WU
17 June 2003
Tel: 2869 9644
-------------------------------------------------------------------------------------------------------------------------------------------Fact sheets are compiled for Members and Committees of the Legislative Council. They are not legal or other
professional advice and shall not be relied on as such. Fact sheets are subject to copyright owned by the
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References
1.
Centers for Disease Control and Prevention, Questions and Answers about
Anthrax.
2.
Center for Civilian Biodefense Strategies, Johns Hopkins University, Anthrax
Fact Sheet 1999.
3.
Department of Health, A fatal case of anthrax infection in 2003, 10 June 2003.
4.
Department of Health, Anthrax, 19 October 2001.
5.
Department of Health, Human Anthrax in Hong Kong in the Past Two Decades,
Public Health and Epidemiology Bulletin,Volume 11: Number 1, February 2002.
6.
Jernigan J.A., Stephens D.S., Ashford D.A., et al. Bioterrorism-related
inhalational anthrax: the first 10 cases reported in the United States, Emerg
Infect Dis 2001; 7: pp. 933-944.
7.
Todar Kenneth, Bacillus anthracis and anthrax, Bacteriology Lecture 2001,
University of Wisconsin-Madison Department of Bacteriology.
Websites
1.
Website of Department of Defense Anthrax Vaccine Immunization Program,
www.anthrax.osd.mil
2.
Website of Centers for Disease Control and Prevention, www.cdc.gov
3.
Website of Department of Health, www.info.gov.hk/dh/
4.
Website of U.S. National Library of Medicine, www.nlm.nih.gov
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