Y. pestis travels to regional lymph node via lymphatics
Replication within lymph node macrophages
Bubo formation
Massive lymph node enlargement from bacterial replication
Surrounding tissue edema and hemorrhagic necrosis
Systemic dissemination
Bacteremia from overwhelmed lymph node barrier
Septicemic plague with endotoxin release
Cytokine storm driving shock and DIC
Pneumonic form
Hematogenous seeding of lungs from bacteremia
Highly infectious respiratory secretions produced
Virulence factors
F1 capsular antigen
Anti-phagocytic properties
Target of rapid diagnostic tests
pla (plasminogen activator)
Facilitates tissue invasion
PCR target for molecular diagnosis
Yersiniabactin iron acquisition system
Essential for survival in iron-limiting host environment
Therapeutic Considerations
Antibiotic mechanism and resistance
Aminoglycosides target 30S ribosomal subunit
Bactericidal activity against Y. pestis
Streptomycin historical gold standard
Gentamicin practical substitute given availability
Fluoroquinolones target DNA gyrase and topoisomerase IV
IMASOY trial 2025 NEJM demonstrated ciprofloxacin noninferior to combination therapy
Emerging evidence supports oral monotherapy for uncomplicated disease
Tetracyclines bacteriostatic at usual doses
Doxycycline first-line oral agent per CDC 2021 guidelines
Penicillin class contraindicated
Intrinsic resistance with 75% case fatality in historical data
Acquired antibiotic resistance rare but documented
MDR Y. pestis isolates reported from Madagascar
Fluoroquinolone resistance surveillance important
Bioterrorism considerations
Y. pestis listed as CDC Category A bioterrorism agent
Highest priority pathogens for public health preparedness
Engineered antibiotic-resistant strains possible threat
Mass casualty event protocols
Strategic national stockpile antibiotics available
Public health emergency declaration criteria
Post-exposure prophylaxis at scale
Doxycycline or ciprofloxacin for close contacts
Coordinated with public health authorities
Vaccine status
No licensed vaccine currently available in US or most countries
Previously available killed whole-cell vaccine discontinued
Subunit F1-V vaccines in development
Pre-exposure prophylaxis not available for general population
Recommended flea and rodent control for endemic area residents
Patient Discharge Instructions
copy discharge instructions
Plague home care instructions
Take all antibiotics exactly as prescribed until finished
Do not stop early even if feeling better
Duration typically 10 to 14 days total
Adequate rest during recovery
Fever and weakness may persist several days
Stay well hydrated
Fluids to replace losses from fever and sweating
Bubo care
Keep wound clean and dry if drainage was performed
Change dressings as instructed
Bubo swelling may take weeks to fully resolve
Warning signs to return to ER immediately
New or worsening cough or coughing up blood
May indicate spread of infection to lungs
Difficulty breathing or shortness of breath
High fever not improving after 48 hours of antibiotics
Confusion, severe headache, or stiff neck
Skin bruising, bleeding, or purple spots
Fainting or severe lightheadedness
Rapid bubo enlargement after starting antibiotics
Unable to keep antibiotics or fluids down
Contact tracing and prevention
Report all household close contacts to public health
Contacts may need preventive antibiotics
Flea prevention measures
Treat pets with veterinarian-approved flea products
Avoid handling wild rodents, rabbits, or animal carcasses
Wear insect repellent in endemic areas
No isolation required at home for bubonic plague without cough
Isolation required only if respiratory symptoms develop
Follow-up instructions
Follow-up with your physician within 24 to 48 hours of discharge
Daily check-in during antibiotic course
Complete the full antibiotic course
Return to ER if any warning signs above develop
References
Guidelines and key sources
Primary guidelines
CDC MMWR 2021 Nelson et al. Antimicrobial Treatment and Prophylaxis of Plague
Recommendations for naturally acquired infections and bioterrorism response
MMWR Recommendations and Reports 2021
JAMA 2000 Inglesby et al. Plague as a Biological Weapon
Medical and public health management
Working Group on Civilian Biodefense consensus statement
Landmark trials and systematic reviews
IMASOY Trial NEJM 2025 Randremanana et al.
Ciprofloxacin versus aminoglycoside-ciprofloxacin for bubonic plague
Demonstrated noninferior outcomes with ciprofloxacin monotherapy
Godfred-Cato et al. Clinical Infectious Diseases 2020
Treatment of human plague systematic review
Antimicrobial efficacy data 1939 to 2019
Jullien et al. Cochrane Database of Systematic Reviews 2020
Rapid diagnostic tests for plague
F1 antigen RDT validation evidence
Epidemiology and outbreak reports
Randremanana et al. Lancet Infectious Diseases 2019
Madagascar urban plague epidemic August to November 2017
Epidemiological characteristics report
Prentice and Rahalison Lancet 2007
Comprehensive plague review
Global epidemiology and clinical management
Bioterrorism and special topics
Adalja Toner Inglesby NEJM 2015
Clinical management of potential bioterrorism-related conditions
Plague management in mass casualty context
Smiley Immunological Reviews 2008
Immune defense against pneumonic plague
Pathogenesis and vaccine development
Coding references
ICD-10 codes for plague
A20.0 Bubonic plague
A20.2 Pneumonic plague
A20.7 Septicemic plague
A20.9 Plague unspecified
SNOMED CT plague disorder concepts
Bubonic plague organism Yersinia pestis
SymptomDx is an educational tool for medical professionals. It does not replace clinical judgment. Verify all clinical data and drug dosages with authoritative sources.