Download Chapter 5 ( Contd.)

Microbes as Bioweapons
Microorganisms as Weapons-history
 Europe, Middle ages – Black plague victims
hurled over city walls to infect citizens.
 Russia, April 2, 1979 – Bioweapons plant
accidentally releases anthrax killing 68 of 94
infected civilians.
INTRODUCTION
 Biological weapons infectious agents (bacteria,
virus, fungi, protozoan etc.) used to intentionally
inflict harm on humans.
 The definition is extended to include biologically
derived toxins and poisons.
 Generally, the types of agents used as biological
weapons cause systemic diseases, hemorrhagic
fevers, pneumonias, or involve toxins and biological
poisons.
What makes a good biological
weapon?
 The microbes should be able to survive outside
of the body, the biological agent must virulent
and lethal
 The weapon should be quick-acting without a
long lag time between dispersal and illness.
 The biological agent should be easily dispersed,
preferably as a powder, and should also be
infectious through person-to-person contact.
The agent should be easy to
weaponise?
 grow in large quantities and not require
sophisticated equipment or training
 The agent should also be inexpensive to grow
in quantity, especially for unfunded terrorists.
 Ability to weaponize.
Bioterrorism Agent Categories
According to the CDC there are three categories:
 Category A – easily spread, cause public panic,
high death rates- Bacillus anthracis, Clostridium
botulinum.
 Category B – moderately easy to spread,
moderate illness rates and low death riskPseudomonas pseudomallei.
 Category C – easily available, easily produced
and spread, potential for high mortality rates and
major health impact- Lassa virus, Ebola Viruses.
The “Top Four” Bioterrorist Agents
B.anthracis, the bacterium that causes
anthrax.
Yersini pestis, the bacterium that causes
plague.
Variola virus, the virus that causes
smallpox.
Botulinum toxin, a protein toxin produced
by Clostridium botulinum, the bacterium
that causes botulism.
The following table is a list of the most likely candidates
for biowarfare and/or bioterrorism for human diseases:
Disease
Symptoms
Treatment
Anthrax
(bacterium)
High Fever, labored breathing
antibiotic, tachycardia
vaccine
Small Pox Fever
(virus)
Headache, vomiting
vaccine, bleeding
cidofovir
Aflatoxin (fungal
toxin)
Nausea, vomiting, then acute liver failure
or cancer (long term)
Botulism (bacteria Nausea, fatigue, cramps, headache,
toxin)
respiratory paralysis
equine antitoxin
Plague
(bacterium)
antibiotic, vaccine
lung infection, pneumonia
Bacillus anthracis- the cause of anthrax
 B. anthracis is a gram-positive spore-forming rod. Spores are
the infective forms for humans and other animals (approx. 1 by
9 micrometers in size).
 Anthrax can enter the human body through the intestines
(ingestion), lungs (inhalation), or skin (cutaneous) and causes
distinct clinical symptoms based on its site of entry.
 The second form of anthrax, the most lethal form, is inhalation
anthrax.
 Spores inhaled into the lungs goes to the lymph nodes of the
chest.
 In the lungs and in the lymph nodes, the spores germinate into
actively dividing bacteria, which begin to produce lethal toxin.
 Anthrax is usually contracted by handling infected animals or
their wool.
Anthrax
Bacillus anthracis, the cause of anthrax
Micrograph of Bacillus anthracis
Small pox
 Smallpox is a devastating and disfiguring disease that
is highly infectious.
 It is caused by Variola virus (also known as smallpox
virus).
 Smallpox in aerosol form can survive for at least 24
hours.
 The smallpox virus is highly infectious at low doses.
 The smallpox patients would be extremely ill with
aching pains and fever and would be hospitalized.
The face of Biological Warfare
…Small pox
Botulin
 Clostridium botulinum produces botulin, a nerve
toxin, causes serious paralytic illness.
 Botulinic toxin is a powerful known toxins:
about one microgram is lethal to humans.
 It blocks nerve function and leads to respiratory
and musculoskeletal paralysis.
…Botulin
Lassa
Lassa Fever
 Caused by the Lassa virus
 After an incubation period of six to twenty-one
days, an acute illness with multi-organ
involvement develops.
 Non-specific symptoms include fever, facial
swelling, muscle fatigue, and mucosal bleeding.
 Lassa virus will infect just about every tissue in
the human body.
…Lassa
Ebola
 Ebola hemorrhagic fever is caused by several
Ebola viruses.
 Ebola viruses are members of the filovirus family.
 People infected with Ebola virus have sudden
fever, weakness, muscle pain and diarrhea, to
name a few.
 Death rates range from 50% to 90%.
..Ebola
Acts of Bioterrorism
Recent incidents:
 Release of sarin gas in a Tokyo subway in
1996
 Anthrax attack on Capitol Hill in 2001
 Ricin scare in Liberty Lake, Washington
How do you combat
Bioterrorism?
How can
Biotechnology help?
Biodefense
 “Improving our nation’s defenses against bioterrorism is a key
part of the U.S. government’s homeland security effort.” –
National Institute of Allergy and Infectious Diseases
(NIAID).
 Biodefense- the procedures involved in taking defensive
measures against attacks using biological agents.
 Vaccines to immunize the public against bioterror attacks.
 Diagnostic Tests for first responders and medical personnel to
help identify exposure and provide treatment.
Provision of therapy available to infected personnel to help
recovery after infection.
….Biodefense Techniques
Field tests
 Antibody based
PCR
 Comparison with DNA
sequences
Biosensors
 For monitoring air and water
conditions
Bioterrorism Countermeasures
 The United States National Institute of Health and
the CDC are developing methods to detect and
remediate biological threats.
Bioterrorism Counter measures
 These incidents have shifted the U.S.’s paradigm.
 We are not safe on American soil.
 In 2003, the Bush administration requested $2.4
billion to fund and research countermeasures.
Vaccination as Countermeasure
 If an attack occurs,
treatment in the form of
antibodies will be
needed.
 Stockpile of drugs and
vaccines necessary for
emergency cases
 Must be administered
before exposure
Emergency Responders
 Emergency response
teams and cleanup
crews for appropriate
handling and removal
of toxic substances.
Unfortunate reality: are
we prepared for a
Biological Warfare?
Biodefense Project
 On July 21, 1994, the U.S. government approved a 10
year, $6 billion program called Project BioShield.
 Project Bioshield has 3 main goals:
 1) relaxation on procedures for bioterrorism related
research grants
2) creating a market for new biomedical
countermeasures
3) permission of unapproved countermeasures for
emergency situations.
 More information can be
found at:
http://www.fas.org/sgp/cr
s/terror/RS21507.pdf.
….Project BioShield
Project BioShield Act passed in 2003:
 Allowed federal agencies (CDC, HHS and
USDA) to use FDA pre-approved products on
civilians or soldiers facing bio-threat hazards.
 Research and development of novel
bioremediation methods are currently being
studied.
 Whatever method used in biodefense, it will
require collaboration of media, public and the
world to maintain a safe environment and
ensure safety of its people.
Biodefense Research
 Development of countermeasures that will work
against a variety of pathogens and/or toxins.
 Develop animal models to support drug and
vaccine efficacy studies.
 Devise novel delivery systems and temperature
stabilization technologies for vaccines and
drugs.
 Design adaptive diagnostic systems that allow
for simple and rapid incorporation of additional
targets.
….Biodefense Research
For more information go
to:
http://www3.niaid.nih.gov/t
opics/BiodefenseRelated/
Biodefense/PDF/biosp200
7.pdf
REFERENCES
Read Anthrax: A Possible Case History:
http://www.cdc.gov/ncidod/EID/vol5no4/inglesby.htm
http://www.newruskincollege.com/maxweber/id16.html
http://69.36.186.201/article.php?art_ofn=nd04wright
http://webnetarts.com/socialjustice/biowar.html
http://www.ph.ucla.edu/epi/bioter/bioterrorexpertwar.
html
http://webs.wichita.edu/mschneegurt/biol103/lecture20
/lecture20.html