bioterrorism Flashcards
Biowarfare
offensive use of biological agents by nations to harm the military of the enemy.
Bioterrorism
Induces widespread fear of infection and death in a civilian population leading to disruption of society, economic losses, etc. for political or social objectives. Bioterrorism can also target crops, domestic animals, water supply. Bioterrorism can be sponsored either by nations, cults or other extremist organizations.
biocrimes
use microbes to attack individuals as in assassination or murder
2 kinds of biothreat agents
- Transmissible infectious agents that spread among people, animals or plants. 2. Toxins that affect exposed people, but do not make them contagious
characteristics of microbes/toxins likely to be used as biothreat
High morbidity/ mortality, person-to-person spread, Low infectious dose, spread by aerosol, Lack of widespread rapid diagnostic tests, Lack of stockpiles of effective drugs, Lack of an vaccine, Lack of widespread immunity, Ability to obtain pathogen and cultivate it in large amounts, Stability of infectious organism in the environment, Potential to be weaponized, Mass casualties that could overwhelm the health care system
describe properties of category A agents that could be used as bioweapons
Highly lethal, easily transmissible, high mortality rates, public panic/ social disruption, require special action for public health preparedness
List category A agents
Bacillus anthracis (anthrax), Clostridium botulinum toxin (botulism), Yersinia pestis (plague), Variola major (smallpox) and other related pox viruses, Francisella tularensis (tularemia) and Viral hemorrhagic fevers like: Arenaviruses (LCMV, Junin, Machupo, Lassa Fever, Bunyaviruses (Rift Valley fever virus), Flaviviruses (Dengue), Filoviruses (Ebola, Marburg)
describeproperties of category B agents that could be used as bioweapons
moderately easy to disseminate, cause moderate morbidity rates and low mortality rates, require enhanced diagnostic capacity, could be genetically enhanced for use as a weapon
List Category B agents- bacteria
Burkholderia pseudomallei (meliodosis), Burkholderia mallei (glanders), Coxiella burnetii (Q fever), Brucella species (brucellosis), Chlamydia psittaci (psittacosis) Rickettsia prowazekii (typhus fever). Foodborne and waterborne pathogens -Vibrio cholerae, Diarrheagenic E. coli, Pathogenic vibrios, Shigella species, Salmonella, Listeria monocytogenes, Campylobacter jejuni, Yersinia enterolitica
List category B agents- toxins
Ricin toxin (Ricinus communis), Epsilon toxin of Clostridium perfringens, Staphylococcus enterotoxin B, Mycotoxins (fungal toxins)
yellow rain
think mycotoxins from fungi. Causes skin damage
List Category B agents- viruses
caliciviruses including noroviruses, hepatitis A, Viral encephalitides (West Nile virus, LaCrosse, California encephalitis, VEE, EEE, WEE, Japanese B encephalitis virus
describe properties of category C agents that could be used as bioweapons
New emerging pathogens that could be engineered for mass dissemination, cause highly virulent infectious diseases, population lacks immunity, potential for high morbidity and mortality, major public health impact
List category C agents
emerging diseases such as SARS, Nipah, hantaviruses, highly pathogenic avian influenza
Signs that a bioweapons incident has occurred
Unusual clinical presentations, clusters of cases of a previously rare disease, or appearance of a previously agriculture-associated disease in urban areas. Report to CDC
How is the health care system prepared to respond to bioweapons incident
- surveillance networks- timely reporting, rapid testing, control spread, isolation and quarantine. 2. stockpiles of equipment, drugs, vaccines, etc have been assembled and can be mobilized anywhere in US within 12 hrs. 3. providing accurate public information. 4. distinguish btw bioweapons event and emerging dz outbreak
How can microbes be genetically engineered to be bioweapons
- enhance virulence- Abx resistant genes, change antigenicity so nobody has protectve Abs, tissue tropism. 2. Construct chimeric microbes by recombinant DNA technology- genes from one organism recombined with genome of another. 3. de novo construction of pathogens - using oligonucleotides.
Smallpox structure
virus- large, enveloped DNA virus in the orthopox family that replicates in the cytoplasm of infected cells, unlike other DNA viruses. Smallpox virions are highly resistant to inactivation by drying.
smallpox clinical features
Fever,headache, limb and back pain, vomiting, apprehension for 3-4 days. Maculopapular rash (mucosa, head, forearms) > vesicles > pustules (firm, tense) > crust > scar. Hemorrhagic smallpox has rapid evolution of localized petechiae and hemorrhages (pregnant women and immunodeficient prone to this malignant form of the disease), bleeding from orifices, DIC and death. Typical rash may not develop.
smallpox transmission
Incubation period 2 to 3 weeks. Virus shed from the pustules and scabs as well as by respiratory secretions from infected patients enters the body by inhalation and/or inoculation through scratches in the skin
smallpox pathophys
During incubation the smallpox virus first replicates locally at the site of inoculation, then is spread by primary viremia to central organs such as spleen and liver, where it is amplified. Secondary viremia spreads virus to many tissues including the skin, where pustules are formed, most intensively in the face and torso. The incubation period ends when symptoms develop.
Immune responses to smallpox
Innate immune responses cause the fever and systemic symptoms, and the pustular rash is the result of a combination of direct virus damage to infected cells in the skin and acquired immunie responses causing inflammation and cell mediated immunity to the infected cells.
smallpox vaccine
live attenuated virus called vaccinia- antigenically related to smallpox virus and propagated in cow skin. Due to smallpox long incubation period, vaccination can be used after exposure.
smallpox variolation
Pus from a lesion from a mild case of smallpox
was scratched into the skin. One local lesion developed, and most vaccinees were then resistant to virulent smallpox. 2% diedPus from a lesion from a mild case of smallpox
was scratched into the skin. One local lesion developed, and most vaccinees were then resistant to virulent smallpox. 2% died
