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Natural history of select agentsNatural history of select agents
The world is awash in The world is awash in microorganismsmicroorganisms
Mostly they go about their businessMostly they go about their businessMany we needMany we needOblivious to mostOblivious to mostA few get crosswiseA few get crosswise
Some of these bad guys we’ve known for thousands of years
Some are newSome used or researched as weaponsSelect Agents
We love to categorize We love to categorize Select agents HHS/FDA/USDA ~ 70
"potential to pose a severe threat to public health and safety”
CDC regulates labs within the U.S.
EU and most developed countries have their own lists
Some researched for bioweapons
Bacillus anthracis-anthrax
Coxiella burnetii-Q fever
Francisella tularensis-tularemia
Variola major-small pox
Yesinia pestis-plague
Brucella suis-brucellocis
Botulinum toxin
Burkholderia mallei-glanders
Ricin toxin
Some other nasty guys out there
Ebola virus
Lassa virus
Marburg Virus
Typhus Rickettsia prowazekii
Crimean-Congo hemorrhagic fever
Vibrio cholerae
Nipah Virus
USDA lists agents with tremendous potential economic impact
Virulent Newcastle Disease
Foot and Mouth Disease
Bovine spongiform encephalopathy (Mad Cow)
Phakopsora pachyrhizi (Asian soybean rust)
Phoma glycinicola (red leaf blotch)
Puccinia triticina (wheat leaf rust)
Natural history of select agentsNatural history of select agents
Did they always have it in for us?Did they always have it in for us?What do they do in their spare time?What do they do in their spare time?Where are new ones coming from?Where are new ones coming from?How do we detect the ones we know How do we detect the ones we know
and identify new ones?and identify new ones?Any special challenges to water systems?Any special challenges to water systems?
Bacillus anthracis
Traits for success in nature make BA dangerous to us
Spore formingAerosolizesReaersolizes
Three infection routesInhalationCutaneousgastrointestinal
Cholera-one of the most feared diseases on earth.
Caused by the bacteria Vibrio cholera
The natural habitat of Vibrio, isn’t our insides, but estuaries
Monsoons bring changes in salinity Monsoons bring changes in salinity and temperature in estuariesand temperature in estuaries
Leading to increased encounters Leading to increased encounters between between VibrioVibrio and copepods and copepods
Filter feeders come in nextFilter feeders come in next
Understanding Understanding VibrioVibrio ecology ecology has broader implicationshas broader implications
How did Vibrio acquire enterobacteriaciae-like toxin?
The ocean is teeming with The ocean is teeming with phages (1-10 million/ml)phages (1-10 million/ml)
Acanthamoeba are everywhereAcanthamoeba are everywhereSoil, freshwater, dirty contact lens, thing the dentist uses to rinse your mouth out
Life cycle includes two stages, a feeding “trophozoite” a dormant cyst.
Trophozoite feeds on bacteria, Trophozoite feeds on bacteria, algae, yeasts, fungi.algae, yeasts, fungi.
Franciscella tularensis Franciscella tularensis (Ft) is the (Ft) is the causative agent of Tularemia.causative agent of Tularemia.
Several select agents are obligate or Several select agents are obligate or facultative intracellular bacteria.facultative intracellular bacteria.
• Coxiella multiplies strictly inside the amoeba,
• Brucella, Francisella, and Yersinia are facultative intracellular bacteria
• The ability to survive within host cells originated as a defense mechanism against predation. It now is a pathway to pathogenicity.
Emerging Infectious Diseases Emerging Infectious Diseases
Global emergence of a zoonotic Global emergence of a zoonotic pathogen needs 3 steps. pathogen needs 3 steps.
1.1. Successful transit between a wild reservoir Successful transit between a wild reservoir and humans or domestic animalsand humans or domestic animals
2.2. Direct transmission between humans. Direct transmission between humans. 3.3. Local epidemics into the global population. Local epidemics into the global population.
Many agents move between animal and Many agents move between animal and humans but fail steps 2 and 3humans but fail steps 2 and 3
Environmental changes aid Environmental changes aid emergence of new diseasesemergence of new diseases
Urban centers Urban centers Bush meat economyBush meat economyVillage, town, cityVillage, town, cityHuman behavior Human behavior Global travel Global travel
Known and emerging agents Known and emerging agents challenge our response capability challenge our response capability
How do we detect them
How do we treat them
• How do we respond to them
Detection is built on timescalesDetection is built on timescales
• Detect to intercept-prevent exposure
• Detect to warn-minimize exposure
• Detect to treat- treat exposed people
Three methods of detectionThree methods of detection
• “White powder”
• Epidemiological surveillance
• Widgets
White powder HazMat responseWhite powder HazMat response
• >150,000 anthrax hoaxes 2001-2002
• 2008 >50 white powder letters mailed to JP Morgan Chase bank facilities
Epidemiological surveillanceEpidemiological surveillance
• Traditional surveillance– Background rates of disease. Trends in mortality and
morbidity; disease occurrence – Laboratory confirmation
• Syndromic surveillance in real-time – Computer/internet based– Capture and analyze health data– Identifying abnormal conditions– Early detection of outbreaks
An EPI monitoring systemAn EPI monitoring system
Early detection is criticalEarly detection is critical
Faster and faster widgetsFaster and faster widgets• Culture
• Immunoassay
• PCR
• Particle detection
• Autonomous Systems
Challenges for widgetsChallenges for widgets
Time to an answerTime to an answer
Resources to run the systemResources to run the system
False positive-False negativeFalse positive-False negative
SpecificitySpecificitynear neighborsnear neighborsenvironmental positives and gunkenvironmental positives and gunk
Response and return to serviceResponse and return to service
Economic costs of being wrongEconomic costs of being wrong
Threats to water systemsThreats to water systemsYou guys are lucky!
The path aheadThe path ahead