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tularemia (deer fly fever, Prahvant Valley plague, rabbit fever)

Etiology: infection with Francisella tularensis Epidemiology: - transmitted from rodents a) through the bite of deer flies (Chrysops discalis) or ticks b) handling of infected animal or animal carcass: - transmission via inhalation of airborne particles c) rabbits, muskrat, beavers & squirrels are important reservoirs Clinical manifestations: 1) incubation period is 2-5 days 2) abrupt onset of fever/chills, myalgias & respiratory symptoms 3) prolonged intermittent fever 4) headache, nausea, anorexia, perspiration (case report) [7] 5) cutaneous ulceration 6) lymphadenopathy a) swelling & suppuration of lymph nodes draining the site of infection b) may be generalized, especially if acquired handling infected animal or carcass 7) bronchopneumonia a) cough (common) b) fever (common) c) chest pain (common) 8) sepsis 9) many patients are asymptomatic * images (glandular tularemia) [9,10] Laboratory: - complete blood count - leukocyte count is normal - Francisella tularensis serology - 4-fold increase in titer to > 1:160 - Francisella tularensis antigen - Francisella tularensis in isolate - organism is not seen with gram-stain of sputum - Francisella tularensis nucleic acid - Francisella tularensis DNA - Francisella tularensis A DNA - Francisella tularensis B DNA - Francisella tularensis rRNA - Francisella tularensis A rRNA - Francisella tularensis B rRNA - Francisella tularensis subtype - Francisella tularensis culture - requires biosafety level 3 conditions [9] - gram negative bacillus - also see Francisella tularensis & ARUP consult [5] Radiology: - chest X-ray: 1) hilar adenopathy [4] 2) lower lobe patchy infiltrates a) generally unilateral b) bilateral in 30% of patients 3) pleural effusion (30%) - computed tomography of thorax [7] (image from case report) Differential diagnosis: - plague Management: 1) streptomycin or gentamicin for severe disease 2) tetracycline or doxycycline a) active against Francisella tularensis b) associated with 10% incidence of relapse 3) ciprofloxacin [10] 4) duration of therapy: 7-14 days 5) prophylaxis with ciprofloxacin or doxycycline [4] 6) vaccine: a) not highly effective b) limited supply Notes: - potential agent of bioterrorism [6]

Related

Francisella tularensis

General

fly/gnat-borne infection bacterial infection

References

  1. Stedman's Medical Dictionary 26th ed, Williams & Wilkins, Baltimore, 1995
  2. Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed) Lippincott-Raven, Philadelphia, 1998, pg 500, 798
  3. The Sanford Guide to Antimicrobial Therapy, 29th ed., Gilbert, DN et al (editors), Antimicrobial Therapy, Inc., Hyde Park VT, 1999
  4. Medical Knowledge Self Assessment Program (MKSAP) 15, 16, 17, 18, 19. American College of Physicians, Philadelphia 2009, 2012, 2015, 2018, 2021.
  5. ARUP Consult: Francisella tularensis - Tularemia The Physician's Guide to Laboratory Test Selection & Interpretation https://www.arupconsult.com/content/francisella-tularensis
  6. Dennis DT, Inglesby TV, Henderson DA Tularemia as a biological weapon: medical and public health management. JAMA. 2001 Jun 6;285(21):2763-73 PMID: 11386933
  7. Rothaus C Back to Nature. Now@NEJM http://blogs.nejm.org/now/index.php/back-to-nature/2015/12/04/ - James J, Kaul DR, Goldberger ZD, Saint S, Skerrett SJ. CLINICAL PROBLEM-SOLVING. Back to Nature. N Engl J Med 2015; 373:2271-2276December 3, 2015 PMID: 26630146 http://www.nejm.org/doi/full/10.1056/NEJMcps1407030
  8. Thomas LD, Schaffner W. Tularemia pneumonia. Infect Dis Clin North Am. 2010 Mar;24(1):43-55. Review. PMID: 20171544
  9. Marks L, Spec A. Glandular Tularemia. N Engl J Med 2018; 379:967. Sept 6, 2018 PMID: 30184456 https://www.nejm.org/doi/full/10.1056/NEJMicm1801531
  10. Buettcher M, Imbimbo C. Images in Clinical Medicine. Ulceroglandular Tularemia N Engl J Med 2021; 384:1349. April 8. PMID: 33826822 https://www.nejm.org/doi/full/10.1056/NEJMicm2031676
  11. Yeni DK, Buyuk F, Ashraf A, Shah MSUD Tularemia: a re-emerging tick-borne infectious disease. Folia Microbiol (Praha). 2021 Feb;66(1):1-14. PMID: 32989563 PMCID: PMC7521936 Free PMC article.