Infectious Agents of Bioterrorism

Question 1

Clostridium botulinum

Answer 1

Infectious Agents of Bioterrorism
• Gr+ bacilli
• Anaerobic
• Most potent toxin known in nature; a *potential weapon of bioterrorism
- *toxin blocks release of ACH
• *Endospore forming
- *terminal endospores make the bacterium appear *swollen or club shaped
• Relatively heat-resistant
• Can contaminate meats, vegetables & fish
LAB
• Endospores of Clostridium botulinum can be seen using the *malachite green staining method
TYPES OF BOTULISM
• Foodborne botulism
- Consuming food containing botulinum *toxin
• Begins with cranial nerve palsies and develops into descending weakness and symmetric motor paralysis (descending *flaccid paralysis)
• Infant botulism
- Consuming *endospores; HONEY!; most common form in U.S.
• Symptoms are initially nonspecific (e.g., constipation, weak cry, lethargy, poor feeding or “failure to thrive”)
• Progressive disease with flaccid paralysis and respiratory arrest can develop; “floppy” or hypotonic state
• Wound botulism
- Toxin produced from a wound infected with C. botulinum *endospores
• Usually due to a traumatic wound getting contaminated by endospores
• Also associated with IVDU with black tar heroin
TX
- *Horse botulinum antitoxin (serum sickness) or human botulism immune globulin
PREVENTION
- Proper canning
- No honey for infants

Question 2

Francisella Tularensis

Answer 2

Infectious Agents of Bioterrorism
• Small, Gr- coccobacillus
• Non-motile
• Facultative anaerobe
• Facultative intracellular
• Non-spore-forming, yet survives well in the environment
- *transmission through arthropod bite (tick, deer fly, etc)
• *Tularemia is a zoonotic disease as the bacteria can infect many different animals & insects, especially rabbits, muskrats, squirrels
- *replicates in MACS
DISEASE
1. Ulceroglandular tularemia
• Most common type of tularemia (80%)
• Usually by insect bite or tissue exposure
• Ulcers/eschar
• Regional lymphadenopathy
2. Pneumonic tularemia
• Due to aerosols;
- **lawn mowers/laboratory exposure/bioterrorism
• Pneumonia; respiratory failure
3. Typhoidal Tularemia
• Inhalation exposure or skin/mucosal contact
• May be due to bioterrorism
• Systemic infection without lymphadenopathy or ulcer; sepsis, pneumonia
4. Oropharyngeal tularemia
• From consuming contaminated food/water; inhalation
• Exudative pharyngitis and cervical lymphadenopathy
5. Oculograndular tularemia
• Usually from butchering infected animal and getting the spray in one’s eyes
• Conjuctival inflammation with preauricular lymphadenopathy and periorbit
TX
• Treatment with parenteral *streptomycin (or gentamycin) for severe infections
• In large-scale outbreaks, *doxycycline and ciprofloxacin are the preferred antibiotics due to oral administration

Question 3

Yersinia pestis

Answer 3

Infectious Agents of Bioterrorism
• Pleomorphic Gr- bacilli
• Bipolar staining; “safety pins”
• Facultative anaerobe
• Primarily animal pathogens
• Oxidase-negative
• Non-lactose fermenting 
• Non-motile; non-spore-forming
• Catalase positive
• transmitted by Flea (Xenopsylla cheopis) bites +rats
   - *sylvatic cycle and *urban cycle
VIRULENCE
- *F1 capsule
- *Yops proteins (via T3SS)
- Plasminogen activator (Pla)
- V and W antigens
- LPS endotoxin
DISEASE
Bubonic plague
• Fever, headache, chills, weakness & one or more swollen, tender & painful lymph nodes (buboes)
• Without treatment, may lead to septicemic/pneumonic plague; 50% case fatality
Septicemic plague
• Fever, chills, extreme weakness, abdominal pain, shock & possibly bleeding into skin & other organs; gangrene of fingers, toes & nose 
• 100% fatal without treatment
Pneumonic plague
• Via inhaled droplets (incubation of 2-3 days), or untreated bubonic or bubonic/septicemic plague
• *Can spread person-to-person
- Fever headache, weakness 
- rapidly developing pneumonia (shortness of breath, chest pain, cough & bloody mucous); 
- respiratory failure & shock; 
- untreated is invariably fatal
TX
• IV gentamicin and/or fluoroquinolones
•	Post-exposure prophylaxis w/ Usually doxycycline or ciprofloxacin

Question 4

Bacillus Anthracis

Answer 4

Infectious Agents of Bioterrorism
• large Gr+ rod w/ square ends, single, pairs,*chains
• *endospore-former
• aerobe to facultative anaerobe
• nonfastidious, nutrient agar, blood agar
VIRULENCE
• *protein capsule
– poly-D-glutamate
• survives and replicates in *macrophages
• AB exotoxin comple
LAB
• CXR: **mediastinal widening, pleural effusions
• Gram stain and culture sputum (blood, CSF)
DISEASE
• symptoms nonspecific, viral-like early → rapidly progresses to hemorrhagic mediastinitis, bloody pleural effusions, septicemia, meningitis, death
– symptoms can include fever and chills, chest discomfort, shortness of breath, confusion or dizziness, cough, nausea, vomiting, stomach pains, headache, diaphoresis (often drenching), extreme tiredness, body aches