Q fever pathophysiology: Difference between revisions

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====Large cell form:====
====Large cell form:====
The active form of the [[organism]]
The active form of the [[organism]]
Large cell form persists in the [[macrophages]] inside acidic vacuoles.
large cell form persists in the [[macrophages]] inside acidic vacuoles.
   
   
*Small and large cell forms are [[Antigen|antigenically different]] and this plays a role in the [[virulence]] of the [[organism]].
*Small and large cell forms are [[Antigen|antigenically different]] and this plays a role in the [[virulence]] of the [[organism]].

Revision as of 16:33, 27 June 2017


Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

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Overview

Q fever is a disease caused by C. brutenii, an intracellular gram-negative proteobacterium. The disease can have a wide range of clinical presentations and affect many organ systems due to the unique virulence factors of the organism.

Pathophysiology

Transmission:

The organism is transmitted through:[1]

  • Aerosoloes: Inhalation of contaminated aerosoles is the main mode of transmission.
  • Ingestion of raw dairy products
  • Vertical (mother to fetus) transmission has been reported
  • Parentral
  • Through tick bites

Pathogenesis:

C. Brutenii has the ability to exist in 2 forms:

Small cell form:[2]

Often described as the spore form of C. Brutenii Resists the external environmental factors as heat, pressure and disinfectants for long periods.

Large cell form:

The active form of the organism large cell form persists in the macrophages inside acidic vacuoles.

The infection has 2 phases that correlate with changes in the lipopolysaccharide of C. Brutenii:[3]

    • Phase I: characterized by smooth lipopolysaccharide capsule. Despite being less efficient in the invasion of host cells, antibodies against phase I is always isolated from acute Q fever patients.
    • Phase II: characterized by rough lipopolysaccharide capsule and antibodies against phase II have been isolated from chronic Q fever patients.

Q fever as a biological weapon:

  • Because of its route of infection it can be used as a biological warfare agent.
  • Q-fever is category "B" agent. It is highly contagious and very stable in aerosols in a wide range of temperatures.
  • Just 1-2 particles are enough to infect an individual.
  • Q-fever microorganisms may survive on surfaces up to 60 days (like sporulating bacteria).
  • According to WHO estimates[4], an amount of 50 kg of C. Brutenii if spread in an area of 2 square kilometers is capable of:
  • Infecting 500,000 humans
  • Killing 150 individuals
  • Causing acute illness in 125,000 individuals
  • Causing chronic illness in 9,000 individuals

Microscopic pathology:

Coxiella brutenii
Immunohistochemical detection of Coxiella burnetii in resected cardiac valve of a 60-year-old man with Q fever - By Mahamat A, Edouard S, Demar M, Abboud P, Patrice J-Y, La Scola B, et al. -Public domain-, via Wikime

References

  1. Marrie TJ (1990). "Q fever - a review". Can. Vet. J. 31 (8): 555–63. PMC 1480833. PMID 17423643.
  2. "Diagnosis of Q Fever".
  3. Choyce DP (1992). "Anterior chamber lens exchange". J Cataract Refract Surg. 18 (5): 537. PMID 1489455.
  4. "apps.who.int" (PDF).
  5. "Q Fever on JSTOR".

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