Tularemia in Emergency Medicine 

  • Author: Kelly Maurelus, MD; Chief Editor: Rick Kulkarni, MD   more...
 
Updated: Apr 19, 2011
 

Background

First described in Japan in 1837, tularemia is an infectious disease caused by the gram-negative pleomorphic bacterium, Francisella tularensis. The disease name relates to the description in 1911 of a plaguelike illness in ground squirrels in Tulare County, California, and the subsequent work performed by Dr Edward Francis. In 1928, Francis described his personal experience with more than 800 cases.

F tularensis is found worldwide in more than 100 species of wild animals, birds, and insects. This occurs in both terrestrial (rabbits, hares, ticks, and flies) and aquatic animals (muskrats and beavers). Four major strains, which differ in both virulence and geographic range, exist. The "tularensis" strain, found primarily in North America, is the most virulent.

The organism produces an acute febrile illness in humans. The route of transmission and factors relating to the host and the organism influence the presentation.

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Pathophysiology

Categories of tularemia

Some authorities classify tularemia into 2 groups, which include the far more common ulceroglandular form (in which local or regional symptoms and signs predominate) and the more lethal typhoidal form (in which systemic symptoms dominate the clinical picture). More commonly, however, tularemia is divided into 6 forms:

  • Ulceroglandular
  • Glandular
  • Oculoglandular
  • Oropharyngeal
  • Pneumonic
  • Typhoidal

Each form reflects the mode of transmission. The organism gains access to the host by means of inoculation into skin or mucous membrane, inhalation, or ingestion. Although person-to-person transmission does not occur with F tularensis, the organism is extremely infectious, with as few as 10-50 inhaled organisms producing disease. It is therefore an organism that can infect laboratory technicians working with the organism, making it a candidate for use as a biological weapon.

Ulceroglandular form (70-80% of cases): The organism enters through a scratch, abrasion, or tick or insect bite and spreads via the proximal lymphatic system. Within the ulceroglandular form, more differentiation exists. A subcutaneous inoculum of as few as 10 organisms can cause disease.

Glandular form (rare): No ulcer is present, and the organism is presumed to have gained access to the lymphatic system and/or bloodstream through clinically unapparent abrasions.

Oculoglandular form (1% of cases): The organism enters through the conjunctiva from either a splash of infected blood or rubbing the eyes after contact with infectious materials (eg, blood from a rabbit carcass).

Oropharyngeal form (rare): This form occurs after ingestion of eating undercooked rabbit meat containing the organism.

Pneumonic form (uncommon): This form occurs when the organism is inhaled. This form is observed in laboratory workers and occasionally occurs naturally. Pneumonia also occurs in 10-15% of patients with ulceroglandular tularemia and in one half of those patients with typhoidal tularemia.

Typhoidal (or septicemic) form (10-15% of cases): This form is more severe than the others and often includes pneumonia. Ingestion may be the mode of transmission; however, in most cases, the portal of entry remains unknown.

Incubation

After an incubation period of 3-4 days (range, 1-14 d), a papule develops, accompanied by a high fever. The papule evolves into an ulcer associated with regional lymphadenopathy. Some patients infected by a second, less virulent strain (type B) have less dramatic presentations.

Carriers

Although numerous animals and insects can carry F tularensis, rabbits and ticks (especially Dermacentor and Amblyomma species) most commonly are implicated in human cases. The deer fly is another classic, although less common, vector.

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Epidemiology

Frequency

United States

A few hundred cases of tularemia are reported annually in the United States. As with most such diseases, most cases are likely unreported or misdiagnosed. Although sporadic cases occur in all states, those with highest prevalence are Arkansas, Illinois, Missouri, Texas, Oklahoma, Utah, Virginia, and Tennessee. Some occupations confer risk for tularemia; they include laboratory workers, landscapers, farmers, veterinarians, hunters, trappers, cooks, and meat handlers.

The frequency of tularemia has decreased markedly over the last 50 years, and a shift from winter disease (usually from rabbits) to summer disease (more likely from ticks) has occurred. Although this decrease led to the Centers for Disease Control and Prevention (CDC) removing tularemia from its list of reportable diseases in 1994, it was reinstated in 2000 due to concerns about tularemia being used as a biological weapon.

International

Tularemia is found worldwide, but the incidence is unknown.

Mortality/Morbidity

Untreated, tularemia has a mortality rate of 5-15%; this rate is even higher with the typhoidal form. Appropriate antibiotics lower this rate to about 1%.

Sex

Biologically, no gender bias exists; however, young–to–middle-aged men may be more likely to engage in activities (eg, associated with tick bites, rabbit, and wild game exposure) that predispose them to tularemia. Recently, tularemia has been associated with the bite of a pet hamster.[1]

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Contributor Information and Disclosures
Author

Kelly Maurelus, MD  Resident Physician, Department of Emergency Medicine, Kings County Hospital, State University of New York Downstate

Kelly Maurelus, MD, is a member of the following medical societies: American Medical Student Association/Foundation and Student National Medical Association

Disclosure: Nothing to disclose.

Coauthor(s)

Richard H Sinert, DO  Associate Professor of Emergency Medicine, Clinical Assistant Professor of Medicine, Research Director, State University of New York College of Medicine; Consulting Staff, Department of Emergency Medicine, Kings County Hospital Center

Richard H Sinert, DO is a member of the following medical societies: American College of Physicians and Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Specialty Editor Board

Dan Danzl, MD  Chair, Department of Emergency Medicine, Professor, University of Louisville Hospital

Dan Danzl, MD is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, American Medical Association, Kentucky Medical Association, Society for Academic Emergency Medicine, and Wilderness Medical Society

Disclosure: Nothing to disclose.

Francisco Talavera, PharmD, PhD  Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Senior Pharmacy Editor, eMedicine

Disclosure: eMedicine Salary Employment

Jon Mark Hirshon, MD, MPH  Associate Professor, Department of Emergency Medicine, University of Maryland School of Medicine

Jon Mark Hirshon, MD, MPH is a member of the following medical societies: Alpha Omega Alpha, American Academy of Emergency Medicine, American College of Emergency Physicians, American Public Health Association, and Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

John D Halamka, MD, MS  Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center

John D Halamka, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Chief Editor

Rick Kulkarni, MD 

Rick Kulkarni, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Emergency Medicine, American College of Emergency Physicians, American Medical Association, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine

Disclosure: WebMD Salary Employment

References
  1. CDC. Tularemia associated with a hamster bite--Colorado, 2004. MMWR Morb Mortal Wkly Rep. Jan 7 2005;53(51):1202-3. [Medline].

  2. Evans ME, Gregory DW, Schaffner W, McGee ZA. Tularemia: a 30-year experience with 88 cases. Medicine (Baltimore). Jul 1985;64(4):251-69. [Medline].

  3. Matero P, Hemmila H, Tomaso H, et al. Rapid field detection assays for Bacillus anthracis, Brucella spp., Francisella tularensis and Yersinia pestis. Clin Microbiol Infect. Jan 2011;17(1):34-43. [Medline].

  4. Perez-Castrillon JL, Bachiller-Luque P, Martin-Luquero M, et al. Tularemia epidemic in northwestern Spain: clinical description and therapeutic response. Clin Infect Dis. Aug 15 2001;33(4):573-6. [Medline].

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  7. Dennis DT, Inglesby TV, Henderson DA, et al. Tularemia as a biological weapon: medical and public health management. JAMA. Jun 6 2001;285(21):2763-73. [Medline].

  8. Eliasson H, Broman T, Forsman M. Tularemia: current epidemiology and disease management. Infect Dis Clin North Am. Jun 2006;20(2):289-311, ix. [Medline].

  9. Ellis J, Oyston PC, Green M, Titball RW. Tularemia. Clin Microbiol Rev. Oct 2002;15(4):631-46. [Medline].

  10. Foley JE, Nieto NC. Tularemia. Vet Microbiol. Jan 27 2010;140(3-4):332-8. [Medline].

  11. Ikaheimo I, Syrjala H, Karhukorpi J, et al. In vitro antibiotic susceptibility of Francisella tularensis isolated from humans and animals. J Antimicrob Chemother. Aug 2000;46(2):287-90. [Medline].

  12. Jacoby I. Francisella tularensis (tularemia) attack. In: Ciottone G, ed. Disaster Medicine. Philadelphia, Pa: Mosby; 2006.

  13. Langley R, Campbell R. Tularemia in North Carolina, 1965-1990. N C Med J. Jul 1995;56(7):314-7. [Medline].

  14. Limaye AP, Hooper CJ. Treatment of tularemia with fluoroquinolones: two cases and review. Clin Infect Dis. Oct 1999;29(4):922-4. [Medline].

  15. Nigrovic LE, Wingerter SL. Tularemia. Infect Dis Clin North Am. Sep 2008;22(3):489-504, ix. [Medline].

  16. Penn RL, Kinasewitz GT. Factors associated with a poor outcome in tularemia. Arch Intern Med. Feb 1987;147(2):265-8. [Medline].

  17. Schmid GP, Kornblatt AN, Connors CA, et al. Clinically mild tularemia associated with tick-borne Francisella tularensis. J Infect Dis. Jul 1983;148(1):63-7. [Medline].

  18. Staples JE, Kubota KA, Chalcraft LG. Epidemiologic and molecular analysis of human tularemia, United States, 1964-2004. Emerg Infect Dis. Jul 2006;12(7):1113-8. [Medline].

  19. Thomas LD, Schaffner W. Tularemia pneumonia. Infect Dis Clin North Am. Mar 2010;24(1):43-55. [Medline].

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Ulceroglandular tularemia on the face. Courtesy of Dr Hon Pak.
Ulceroglandular tularemia on an extremity. Courtesy of Dr Hon Pak.
Ulceroglandular type of tularemia on the hand. Courtesy of Dr Hon Pak.
 
 
 
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