Presentation on theme: "Microbes as Bioweapons"— Presentation transcript:
1Microbes as Bioweapons Chapter 3- contd.Microbes as Bioweapons
2Microorganisms 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.
3INTRODUCTIONBiological 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.
4What makes a good biological weapon? The microbes should be able to survive outside of the body, the biological agent must virulent and lethalThe 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.
5The agent should be easy to weaponise? grow in large quantities and not require sophisticated equipment or trainingThe agent should also be inexpensive to grow in quantity, especially for unfunded terrorists.Ability to weaponize.
6Bioterrorism 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 risk- Pseudomonas pseudomallei.Category C – easily available, easily produced and spread, potential for high mortality rates and major health impact- Lassa virus, Ebola Viruses.
7The “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.
8The following table is a list of the most likely candidates for biowarfare and/or bioterrorism for human diseases:DiseaseSymptomsTreatmentAnthrax (bacterium)High Fever, labored breathingantibiotic, tachycardia vaccineSmall Pox Fever (virus)Headache, vomitingvaccine, bleeding cidofovirAflatoxin (fungal toxin)Nausea, vomiting, then acute liver failure or cancer (long term)Botulism (bacteria toxin)Nausea, fatigue, cramps, headache, respiratory paralysisequine antitoxinPlague (bacterium)lung infection, pneumoniaantibiotic, vaccine
9Bacillus 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.
11Bacillus anthracis, the cause of anthrax Micrograph of Bacillus anthracis
12It is caused by Variola virus (also known as smallpox virus). 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.
14BotulinClostridium 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.
16Lassa 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.
18Ebola 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%.
20Acts of Bioterrorism Recent incidents: Release of sarin gas in a Tokyo subway in 1996Anthrax attack on Capitol Hill in 2001Ricin scare in Liberty Lake, Washington
21How do you combat Bioterrorism? How can Biotechnology help?
22Biodefense“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.
23….Biodefense Techniques Field testsAntibody basedPCRComparison with DNA sequencesBiosensorsFor monitoring air and water conditions
24Bioterrorism Countermeasures The United States National Institute of Health and the CDC are developing methods to detect and remediate biological threats.
25Bioterrorism 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.
26Vaccination as Countermeasure If an attack occurs, treatment in the form of antibodies will be needed.Stockpile of drugs and vaccines necessary for emergency casesMust be administered before exposure
27Emergency RespondersEmergency response teams and cleanup crews for appropriate handling and removal of toxic substances.
28Unfortunate reality: are we prepared for a Biological Warfare?
29Biodefense ProjectOn 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 grants2) creating a market for new biomedical countermeasures3) permission of unapproved countermeasures for emergency situations.
30More information can be found at: http://www. fas More information can be found at: s/terror/RS21507.pdf.
31….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.
32Biodefense ResearchDevelopment 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.
33….Biodefense ResearchFor more information go to:
34Read Anthrax: A Possible Case History: REFERENCESRead Anthrax: A Possible Case History:html/lecture20.html