Infective dose extremely low: 10-50 organisms by inhalation
Type A (F. tularensis subsp. tularensis): more virulent, North America
Type B (F. tularensis subsp. holarctica): less virulent, Europe and North America
Intracellular survival mechanism
Survives and replicates within macrophages and other phagocytes
Escapes phagosomal killing by inhibiting phagosome-lysosome fusion
Spreads to regional lymph nodes, then hematogenously
Pulmonary pathology
Primary pneumonic form
Direct inhalation of organisms reaches alveoli
Alveolar macrophages engulf bacteria but fail to kill them
Neutrophilic and macrophage inflammatory infiltrates develop
Necrotizing granulomatous inflammation in severe cases
Secondary pneumonic form
Hematogenous seeding of lungs from another primary site
Associated with bacteremia and systemic illness
Histopathology
Necrotizing granulomas with central necrosis
Peribronchial and interstitial lymphocytic infiltrates
Organizing pneumonia patterns in subacute presentations
Immune response
Innate immunity
Initial inflammatory response; TLR2 and TLR4 activation
Cytokine storm in severe cases (TNF-alpha, IL-6, IL-1beta)
Adaptive immunity
Cell-mediated immunity critical for clearance
Antibody response (IgM then IgG) forms basis of serologic diagnosis
Immunosuppression markedly worsens prognosis
Therapeutic Considerations
Antibiotic mechanism of action
Aminoglycosides (gentamicin, streptomycin)
Bactericidal: inhibit 30S ribosomal subunit; protein synthesis disruption
Penetrate intracellular compartments to reach F. tularensis
Historical gold standard with extensive clinical evidence
Fluoroquinolones (ciprofloxacin, levofloxacin)
Bactericidal: inhibit DNA gyrase and topoisomerase IV
Excellent intracellular penetration and oral bioavailability
CID 2024 fluoroquinolone data show high efficacy for severe Type B tularemia
Doxycycline
Bacteriostatic: inhibits 30S ribosomal subunit
Good intracellular penetration but higher relapse rates (5-15%)
Adequate for mild disease when aminoglycosides and fluoroquinolones unavailable
Treatment duration considerations
Severe disease
10-14 days parenteral aminoglycoside therapy
Transition to oral fluoroquinolone to complete 14-21 day course
Mild-moderate disease
14-21 days oral fluoroquinolone
Duration extended if slow clinical response
Relapse risk factors
Short antibiotic courses < 10 days
Doxycycline monotherapy
Immunosuppressed host
Treatment response monitoring
Fever defervescence
Expected within 24-72 hours with appropriate antibiotics
Persistent fever beyond 5 days suggests treatment failure or complication
Imaging response
Radiographic improvement may lag clinical recovery by days to weeks
Follow-up imaging at 6-8 weeks to exclude malignancy masquerade
Bioterrorism context
Strategic National Stockpile medications available for mass casualty
CDC MMWR 2025 recommendations govern post-exposure prophylaxis protocols
Patient Discharge Instructions
copy discharge instructions
Discharge instructions for tularemia
Your diagnosis
You have been treated for tularemia, a bacterial infection caused by Francisella tularensis
This infection is acquired from animals, ticks, deerflies, or contaminated water — not from other people
Tularemia does not spread person-to-person; no isolation from family is needed
Medications
Take all prescribed antibiotic doses for the full course (14-21 days)
Do not stop antibiotics early even if you feel better; stopping early can cause relapse
Do not take penicillin or amoxicillin-type antibiotics — they do not work for tularemia
Activity and recovery
Rest during the recovery phase; fatigue and weakness may persist for weeks
Gradually increase activity as strength returns
Full recovery may take several weeks after completing antibiotics
Follow-up
Return to clinic or your doctor in 48-72 hours to assess treatment response
A follow-up chest X-ray may be needed 6-8 weeks after discharge
Inform your doctor immediately if symptoms worsen or you develop new symptoms
Return to emergency department immediately if
High fever returns or does not improve within 2-3 days of starting antibiotics
Worsening shortness of breath or difficulty breathing
Chest pain that is severe or worsening
Dizziness, fainting, or severe weakness
Confusion or altered mental status
Inability to take medications due to vomiting
Any symptoms that concern you or feel severe
References
Guidelines and key sources
CDC MMWR 2025
Nelson CA, Meaney-Delman D, Fleck-Derderian S, Winberg J, Mead PS
Tularemia Antimicrobial Treatment and Prophylaxis: CDC Recommendations for Naturally Acquired Infections and Bioterrorism Response — United States, 2025
MMWR Recommendations and Reports 2025; PMID 41026652
JAMA Bioterrorism Consensus 2001
Dennis DT, Inglesby TV, Henderson DA, et al
Tularemia as a Biological Weapon: Medical and Public Health Management
JAMA 2001;285(21):2763-2773
European Journal of Internal Medicine 2025
Antonello RM, Giacomelli A, Riccardi N
Tularemia for Clinicians: An Up-to-Date Review on Epidemiology, Diagnosis, Prevention and Treatment
Eur J Intern Med 2025; PMID 40107886
CID Fluoroquinolone Outcomes 2024
Widerström M, Mörtberg S, Magnusson M, Fjällström P, Johansson AF
Treatment Outcome of Severe Respiratory Type B Tularemia Using Fluoroquinolones
Clin Infect Dis 2024; PMID 38294118
Frontiers in Microbiology 2023
Maurin M, Pondérand L, Hennebique A, et al
Tularemia Treatment: Experimental and Clinical Data
Front Microbiol 2023; PMID 38298538
Lancet Infectious Diseases 2016
Maurin M, Gyuranecz M
Tularaemia: Clinical Aspects in Europe
Lancet Infect Dis 2016; PMID 26738841
International Journal of Infectious Diseases 2026
Zaghdoudi A, Robin F, Moulinie J, et al
Pulmonary Tularemia: A Diagnosis Not to Overlook
Int J Infect Dis 2026; PMID 41482246
Infection 2024
Vacca M, Wilhelms B, Zange S, et al
Thoracic Manifestations of Tularaemia: A Case Series
Infection 2024; PMID 38457094
Pediatric Pulmonology 2023
Schwarzová V, Schwarz J, Mitrová K, et al
Pulmonary Tularaemia in a Female Adolescent with Inflammatory Bowel Disease Receiving Infliximab: Do Not Miss the Diagnosis
SymptomDx is an educational tool for medical professionals. It does not replace clinical judgment. Verify all clinical data and drug dosages with authoritative sources.