Agents Of Bioterrorism Flashcards
Select agents
A substance that has the potential to pose a severe threat to the public animal or plant health
Tier 1/category A agents
Uber bad
Anthrax
Burkholderia/pseudomallei
Clostridium botulism
Ebola
Marburg
Smallpox
variola major/minor virus
plague (yersinia pestis)
Steps to take during select agents
PPE
Disinfection
Inform
Vaccinate
Bacillus anthracis
Capsules rod, gram positive, spore forming, chained, bacteria that produces spores that can last over 40 years
- only bacteria that possesses polypeptide capsule over polysaccharide*
- Medusa head colonies
Infects via:
- inhalation (woolsorters disease) worst one
- Cutaneous
- GI / injections
Toxins of anthrax
PA: protective antigen that pore forms in host cells
LF: lethal factor that suppresses immunity and kills cells via halting MAPKinases
EF: edema factor that causes cell and tissue swelling by super upregulating cAMP
Pathogenesis of inhaled anthrax
Spores inhaled
Spores are phagocytosis in lung
Phagocytes transported to mediastinal lymph nodes
Phagocytes are lysed in LNs and produce toxin
Cause hemorrhagic mediastinitis and sepsis (death)
Presentation clinically of inhalation anthrax
- Does not transmit from person-person*
- only cutaneous is transmitable
Fever, headache chest discomfort and shortness of breath
Chronic symptoms are pulmonary hemorrhage and shock. Produce meningitis sometimes.
Imaging shows widening of mediastinum, blood fluid in lungs and enlarged LNs
Is deadly because it progresses to shock and death very rapidly
Treatment of anthrax
Prophylaxis immediately for 60 days w/ antibodies
- can potentially stop right there
3 dose of vaccine (0,2,4 weeks respectively)
- both pre and post symptoms
Antitoxins only for post symptom
- anthrax immune globulin
- raxibacumab
- both target Protective antigens on anthrax toxins*
Yersinia pestis (Black Death, Bubonic plague)
Gram negative, facultative intracellular rod that is oxidase, lactase negative
- stains bipolar which appears a “safety pin” structure
Vectored by fleas on rodents such as rats/rabbits
Most common forms of plaque
Bubonic plaque/Buboes (most common in inguinal/axillary LNs)
- only one with swollen painful lymph nodes
- weakest of the three
Pneumonic plaque ( most common in lungs) - highest mortality rate (near 100%)
Septicemic plaque ( most common in GI) - second highest mortality rate
Tularemia (rabbit fever)
Caused by Franciscella tularensis
- fastidious, gram-negative, aerobic coccobacillus
- intracellular pathogen
Vectors include (summer) ticks, deer flies and (winter) rabbits mainly
Has an extremely low infectious dose (1 bacillus) 2nd lowest of tier 1 pathogens!!
- will not transmit person-person*
Clinical presentation of tularemia
Depends on route of infection
Ulceroglandular: skin abrasions/ bites
Pneumonic: inhalation
Oropharyngeal: ingestion of meat
Typhoidal: systemic spread
Ulceroglandular tularemia
most common form
Inhibits phagosome-lysosome fusion which develops a painful papule/ulcer at site (bacteria survives within cells)
- not very fatal
Presents with lymphadenopathy also as well as fever, chills, malaise and myalgia
Pneumonic tularemia
Highest rate of mortality in tularemia
Produces multiple necrotizing granulomas in the alveolar
Causes bronchopneumonia, bronchitis with lobar pneumonia
Can cause bacteremia
Oropharyngeal tularemia
High mortality rate just under pneumonic tularemia
Caused by ingested bacteria, which crosses the mucosa and enters blood stream
- produces endotoxemia which causes sepsis
Symptoms = fever, sore throat, ab pain, splenomegaly, vomiting, diarrhea
Oculoglandular tularemia
Rarest form of tularemia with low mortality and is exclusively caused by rubbing the eyes with infected hands
Bacteria inoculates within the eye and nearby lymph nodes
- pain itching, photophobia, intense ocular congestion, mucopurulent discharge
Typhoidal tularemia
Mortality rate is highest or tied with pneumonic
- a combination of pneumonic and oropharyngeal
Most often caused by bite that puts the bacteria directly into the blood
Presents with fever, chills, myalgia, malaise without ulcers and lymphadenopathy
- produces sepsis shock
Ebola
Filovirus that produces hemorrhagic fevers with super high mortality rates (90%)
Suspected vector is African fruit bat
Acute symptoms:
Fever, headache, sore throat, myalgia
Chronic symptoms: vomiting, ulcers, rash, diarrhea
Kills via internal/external bleeding shock and death
- is transmitable via person-person
Brucellosis (brucella)
4 main species
- abortus: cattle
- canis: dogs
- suis: swine
- melitensis: goats/sheep
Most infections occur via raw/unpasteurized milk
Fastidious, gram negative aerobic coccobacillus that is an facultative intracellular pathogen
- So many different presentations*
- common is undulating fevers with malasie, back fain, fatigue, lymphadenopathy
Brucellosis chronic issues
Doesn’t really kill, just extreme malaise with undulating fever/malaise
Chronic stages produces abscesses and granulomas with respiratory symptoms
coxiella burnetii (Q fever)
Lowest infectious dose of any pathogen!!!
Most common in vets, farm workers
Obligated intracellular pathogen that produces endospore forms
promotes acidified phagolysosome production and localized to genital tract/mammary glands
Modified Ziehl-Neelsen
A stain that is used to diagnose Q fever
- used in conjunction with a PCR
Which Tier1 agents do we have vaccines for?
Small pox
Botulism toxin
Anthrax
Ebola
(not the greatest though and still investigational)
Tularemia
Diagnosing tularemia
Culture aspirate from lymph nodes and/or sinus drainage
Culture with special agar
Use antibody titers (IgG should be very high however, must rule out brucellosis as well)
Brucella clinical symptoms and pathogenesis
Incubation is variable as is the symptoms
Most common are undulating malaise and fever, back pain and fatigue
Has weak LPS activity (possesses strange LPS that immune system doesn’t recognize) and inhibits phagolysosome fusion
Takes forever to cure (6+ weeks)
