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The Buzz: The Threat of Bioterrorism
by Daniel S. Berger, MD
“When you let the
politicians back into the anthrax-contaminated U.S. Senate
building, there was enough hot air to kill all the spores.”–Physician
comment during a bioterrorism session
Since September 11, defense
funding has taken priority. This coupled with the stalled
U.S. economy has resulted in many dollars being diverted from
other needed programs into planning against bioterrorism.
Although one can appreciate our need for preparedness and
national defense, the national and world AIDS epidemic with
all its inherent complications needs to be placed in perspective
with the war on terrorism. Countless more lives have been
lost to AIDS than all the fatalities of September 11 and anthrax
combined. The rise in the incidence of cases of HIV infection
in young gay males, African Americans and women in the U.S.
as well as the epidemic of resistance to currently available
antiretroviral drugs continues.
As the U.S. prepares for
war with Iraq at this time [early February], potential bioterrorism
and weapons of mass destruction are of serious concern. The
threat of bacteria or other organisms being propelled or dispersed
within our borders is a horror that needs to be considered.
Despite all the hype, little mention has been made regarding
the effect biological warfare can have on immune compromised
individuals. This is a rather large group of persons. It includes
the HIV-positive, infants, elderly, transplant patients and
persons being treated with chemotherapy and radiation for
cancer. Planning to help defend these individuals from
bio-terrorism should be as important as protecting any other
group. Immune compromised individuals by definition may
not be able to mount the same protective response to some
infections that others can.
History of bioterrorism
The use of biological agents
as weapons is not a new phenomenon. The Romans used corpses
of diseased animals to poison the drinking wells of their
enemies. During the horrific Black Death of the Middle Ages,
the bodies of bubonic plague victims were catapulted over
fortress walls of besieged cities. During the French and Indian
wars, 1754-1763, the British gave smallpox-infested blankets
as gifts to the Indians. During World War II, Germany and
Japan produced bacteria capable of infecting humans. In Europe,
terrorist groups in Germany began producing botulinum toxin.
In the late ‘80s in Japan, the Aum Shinrikyo cult acquired
anthrax bacteria and botulinum toxin and attempted to collect
samples of Ebola virus. Following the 1991 Persian Gulf War,
United Nations inspectors revealed the vast scope of Iraq’s
biological arsenal. Iraq was found to possess more than 150
bombs and 25 missile warheads filled with botulinum toxin,
anthrax, or aflatoxin. What’s more, Iraq had built sophisticated
laboratories to study and produce a wide range of biological
agents and toxins. Thus, this form of attack is a real possibility.
Anthrax
Anthrax is a spore-forming
bacteria and commonly occurs in cattle, sheep and other animals,
but can also occur in exposed humans. The bacteria can be
transmitted to skin by direct handling of contaminated products,
inhaled spores or eating contaminated uncooked meat. Infection
is not spread from person to person. Symptoms usually occur
within seven days. The cutaneous form (on the skin) develops
an itchy bump that turns into a blister and then a painless
ulcer that appears black and necrotic in the center. Adjacent
areas may swell.
Inhalation form of anthrax
begins as flu or cold symptoms with fever, chills, sweats
and malaise that progress to breathing problems, chest pains
and or shock. Symptoms can also include nausea, vomiting,
abdominal pain, dyspnea, chest discomfort, myalgias, headache
and confusion. Gastro-intestinal symptoms are usually out
of proportion to a primary respiratory infection. Pulmonary
(lung) infiltrates usually causes pleural effusion (fluid
on the lungs), mediastinal (mid-chest) blood and widening,
and abnormal chest X-ray.
There are concerns regarding
gastrointestinal exposure to anthrax as well as other agents
transmitted through food and water. Several hand held devices
can detect anthrax in food. Intestinal symptoms from consumption
of anthrax contaminated meat are nausea, vomiting and fever
followed by vomiting blood and severe abdominal pain and diarrhea.
For patients who are immune
compromised, including HIV-positive individuals, anthrax infection
can potentially be more rapid and devastating, spreading to
more sites, and perhaps with a higher mortality.
The vaccine for anthrax is
a cell-free filtrate vaccine that does not contain live attenuated
nor dead bacteria in its formulation. Thus patients with HIV
can conceivably be vaccinated for anthrax. The Department
of Defense has begun obligatory vaccination in all military
personnel who are at risk for biological warfare.
While it is recommended to
avoid using the penicillins for treatment of anthrax, many
other antibiotics seem capable of fighting anthrax, including
ciprofloxacin, doxycycline, rifampin, clindamycin, vancomycin,
chloamphenicol and imipenim. Treatment should start as soon
as possible, with combination therapy. An antitoxin is in
research.
Smallpox
Smallpox infection, caused
by variola virus, was eliminated from the general population
in 1977. The onset of symptoms from time of exposure is usually
seven to 17 days. Initial symptoms include high fever, fatigue,
and head and backaches. A characteristic rash, most prominent
on the face, arms, and legs, follows in two to three days.
The rash starts with flat red lesions that evolve at the same
rate. Lesions become pus-filled and begin to crust early in
the second week. Scabs develop and then separate and fall
off after about three to four weeks. The majority of patients
with smallpox recover, but historically, death occurs in up
to 30% of cases in people with a normal immune system.
Smallpox is spread from one
person to another by infected saliva droplets that expose
an individual having face-to-face contact with the ill person.
Persons with smallpox are most infectious during the first
week of illness, because the largest amount of virus is present
in saliva during that time period. However, some risk of transmission
lasts until all scabs have fallen off. Therefore, if even
one individual is found to be infected, it is considered a
medical emergency due to the potential epidemic arising from
one person.
Routine vaccination against
smallpox ended in 1972. The level of immunity, if any, among
persons who were vaccinated before 1972 is uncertain. Additionally,
there are no reliable tests to determine who is protected;
therefore, even these individuals are assumed to be susceptible
to infection.
In non-immune compromised
individuals exposed to smallpox, the vaccine can lessen the
severity of—or even prevent—illness if administered within
four days after exposure. The vaccine against smallpox contains
another virus called vaccinia. However, because the vaccine
is live attenuated, it is contraindicated for persons who
have compromised immune systems. In other words, it is dangerous
to administer this vaccine to HIV-positive individuals. When
a live virus contained in a vaccine is given to an individual
with a damaged immune system, they are at risk to develop
the illness itself, since their immune systems may not be
able to fend off the virus. With other vaccines, persons who
are HIV-positive have been demonstrated to have less benefit
because of their inability to mount a normal immune response.
Vaccination against smallpox is currently not recommended
to prevent the disease in the general public.
There is concern for all
health care workers who may be the first to be exposed to
smallpox should an epidemic begin. The United States currently
has an emergency supply of smallpox vaccine, and the military
and health care providers are now actively being vaccinated
on a voluntary basis. If one is being vaccinated, there are
certain precautions that must be adhered to. First, as the
vaccine is live virus being applied to the skin, the injection
site is a potential source of infection of the pox virus to
others. The injection site should be kept covered with a semipermeable
dressing and care should be given so that no other individuals
are exposed to the injection site—sick, immune compromised
or otherwise. The site should be covered until the scab has
fallen off. Therefore, if one’s hands are exposed or in contact
with the vaccine injection site, they should be thoroughly
washed with disinfectant or soap. Any materials contacting
the site should be properly disposed of or incinerated if
possible. Clothes should be washed thoroughly with hot water
and bleach. If you are an HIV-positive health care worker,
the risks and dangers of developing actual disease through
vaccination is a real one. Thus, vaccination may be contraindicated
as in any person who is immune compromised.
There is no proven treatment
for smallpox, but research to evaluate new antiviral agents
is ongoing. Patients with smallpox can benefit from supportive
therapy (intravenous fluids, medicine to control fever or
pain, etc.) and antibiotics for any secondary bacterial infections
that occur.
An antiviral drug, cidofovir
(Vistide), developed for the treatment of cytomegalovirus
in AIDS, has broad activity to other viruses, including those
in the pox family. Moreover, an often-seen skin complication
of HIV disease caused by pox viruses is molluscum contagiosum.
We have treated severe and resistant molluscum lesions successfully
with the topical form of cidofovir. Cidofovir is administered
intravenously. Its use is complicated by the fact that physicians
should be thoroughly knowledgeable regarding its protocol
for administration. The co-administration of probenicid and
intravenous fluids are a necessary part of treatment because
of possible harmful side effects to the kidneys. Because cidovovir
is long-acting, the potential treatment for smallpox infection
or exposure may only necessitate one dose. However, no testing
in humans has been published. There is ongoing research proposed
for the possible role of cidofovir in combating bioterrorism.
Currently we are not prepared
to deal with the potential emergency of a smallpox epidemic.
Housing in motels has been proposed for patients exposed to
smallpox. The modes of death due to smallpox occurs with bleeding
lesions and internal bleeding that may progress to shock and
death. Motels would not be the best place to deal with this.
A single case is a global emergency. Much planning is in the
works.
A great deal is being learned
while maneuvering through a maze of issues never before encountered.
Most of the learning and decision-making occurs in an incremental
way, piece by piece. Clearly, new protocols and expertise
need to be in place in more areas than could be imagined.
Early response is crucial. Expertise needs to encompass many
scientific fields. A full-scale response should include public
education that does not ignore immune compromised individuals.
Appropriate prevention for them needs to be considered, since
their exposure can lead to rapid disease progression.
Daniel S. Berger, MD is
Medical Director for NorthStar Healthcare, Clinical Assistant
Professor of Medicine at the University of Illinois at Chicago
and editor of AIDSInfosource (www.aidsinfosource.com).
He also serves as medical consultant and columnist for
Positively Aware. Dr. Berger can be reached at DSBergerMD@aol.com
or (773) 296-2400.
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