lecture 13) biowarfare and bioterrorism Flashcards
define biological warfare/bioterrorsim
the deliberate dispersal of toxic agents to kill or incapacitate man and/or destroy or severely damage livestock, crops and disrupt foodchain
why would you aim bioterrorism at livestock and crops?
disrupts economy of a country and makes it more vulnerable
what is the UK’s stance on bioterrorism?
it is inhumane, illegal and entirely unacceptable in a modern world
what is biological warfare?
used in war to gain strategical or tactical advantage in battlefield
attacks armed forces of opposing countries
usually involves nation states
what is bioterrorism?
used against civilians
localised event
state sponsored or extremist groups
give examples of viral biothreat agents
smallpox
ebola
influenze
foot and mouth disease
give examples of bacterial biothreat agents
anthrax
plague
meliodosis
give examples of fungal biothreat agents
coccidomycosis
wheat stem rust
rice blast fungus
give some examples of toxin biothreat agents
botulism toxin
ricin toxin
why would influenze be considered a biothreat agent if it doesnt kill you?
when released over a population it can be incapacitating for several weeks
what is attractive about a biothreat agent?
spread of disease important (if infected individuals can transmit airborne diseases to others, must considered desired outcome and control of epidemic of disease, dont want it to spread further than the target)
potency
if smallpox has been eliminated due to vaccines, why is it on the list of bioweapons?
known stocks in USA and Russia. most likely other countries have stocks that arent disclosed
because smallpox has been eradicated, what risk does this pose to the population?
most people nowadays probably arent vaccinated against smallpox as the infection doesnt exist anymore
what bacterium causes plague?
Yersinia pestis
what is the natural plague classed as?
bubonic
what is the biowarfare plague classed as?
pneumonic plague
airborne route of infection therefore more fatal and faster acting than bubonic plague
give 4 properties of biological weapons
cheap
easy to produce
potent
difficult to attribute
why is it important for a biological weapon to be difficult to attribute?
make it harder for the victims to determine whether it is a natural outbreak or a deliberate attack eg influenza
how would a country determine a bioterrorism attack?
look for atypical patterns of emergence of disease
look for unusual outbreaks
what did the UK establish in WWII in the fight against bioterrorism?
UK public health surveillance
describe the production of bacteria as bioweapons
easy to grow in culture as all you need is growth media with nutrients
describe the production of viruses as bioweapons
harder to produce than bacteria therefore less likely to be used as a bioweapon
where would a terrorist group or nation state get hold of a microorganism to use it as a bioweapon?
prior to 1st iraq war you were able to purchase lots of pathogen culture collections
iraq got these from around the world
now regulated more tightly therefore harder to acquire these culture collections
how was anthrax grown as a biowarfare agent in WWII in the UK?
large-scale batch cultivation
used medium consisting of marmite, molasses and simple salts
grown in milk churns
large volumes of spores could be grown this way
what programme did the UK have during WWII for biowarfare?
offensive bioweapon programme
abandoned in late 1960s
why was anthrax grown as an offensive bioweapon agent?
considered position of last resort
if all else failed and country was invaded, drop anthrax in Germany to kill livestock and debilitate country
what is the main factor of bioweapons that would be most attractive to terrorist groups?
cheap to produce
what are some of the most potent microorganisms that can be used a bioweapons?
plague bacteria
botuilin toxin
VX (nerve toxin)
what is the potency of a microorganism dependent on?
infectious/toxic dose
airborne stability
why is it important to consider the potency of a microorganism?
some are more infectious via different routes eg bubonic vs pneumonic plague
what are the 2 factors to consider with airborne mircoorganisms?
how infectious and how stable they are in air
what is the impact of UV radiation on airborne stability?
most die when exposed to sunlight
what is the impact of rainfall on airborne stability?
washes bacteria out of the air
what is the impact of temperature on airborne stability?
extreme temperatures could mean survival is compromised
what is the impact of airborne chemicals on airborne stability?
pollutants/chemicals in the air are themselves microbicidal
what factor is used to determine what microorganisms survive better in open air that others?
half life (some may have a shorter half life than others when released into the air)
what is the airborne hazard?
in some situations microorganisms can survive for long periods of time in the air eg foot and mouth disease spreading from france, jersey, isle of white and then the UK
how would you attribute a bioterrorism attack?
use genome sequencing to match the sequence against a database of different labs around the world
what is a problem of using genome sequencing as a way of attributing a bioterrorism attack?
gives a population level picture of genetic makeup of bacteria
doesnt let you look for subtle differences in that population
how would you look for subtle differences in strains to attribute bioterrorism attacks?
grow up the strains and look for spontaneous mutants, their morphology and their frequencies
what are the 2 principle ways of controlling the problem?
prohibition of weapon acquisition and production (stop people form getting hold of the microorganisms in the first place) defensive capability (have physical ways of defending ourselves)
what is the main issue with the biological weapons convention 1972?
a lot of people signed it but there is no way to police it
many countries refused inspection regimes
what are some of the other contro measures for bioterrorism?
export control of pathogens, technologies and equipment
security of laboratories
vetting of staff
code of conduct for scientists/microbiologists
refusal to publish papers that aid weapons production
what are some of the options for defensive capability?
detectors and identification equipment
vaccines for treatments for disease
respirators and protective clothing
why are vaccinations for protection of bioweapons considered a ‘political hot potato’?
people may not want them
unlikely that they will be exposed to them
is it ethically right to immunise everyone despite unlikelihood of a bioterrorism attack?
what does the furture of bioterrorism look like?
generally believed the potential for terrorist use will increase
BTWC is weak; no verification
attribution remains a key issue