Felis ISSN 2398-2950

Coxiella burnettii

Synonym(s): C. burnettii

Contributor(s): Melissa Kennedy

Introduction

Classification

Taxonomy

  • Order: Rickettsiales.
  • Family: Rickettsiaceae.
  • Tribe: Rickettsieae.
  • Genus: Coxiella.

Etymology

  • Coxiella: named after Herold R Cox who first isolated this organism in the USA in collaboration with G E Davis soon after it was first discovered in Australia.
  • Burnettii: named after Frank MacFarlane Burnet who first studied the properties of the organism.

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Clinical Effects

Epidemiology

Habitat

  • Survives in the environment.
  • Natural hosts include many species of mammals and arthopods (ticks, fleas, mites, lice and flies).

Lifecycle

  • The organism is disseminated hematogenously.
  • Persists in tissue and multiples in vacoules of the host cell.
  • Endospore-like growth phase occurs - the "small-cell variant".

Transmission

  • In animals via tick bites or aerosols.
  • In humans usually via aerosols. Ruminants ar a major source - many organisms shed from infected animals at parturition.
  • C. burnettii also occurs in milk of cows and sheep but transmission not so likely to occur via the gastrointestinal tract.
  • May be acquired from contaminated wool.
  • Occupational disease of farm workers, slaughterhouse workers and textile workers.

Pathological effects

  • Ruminants: sporadic abortions, weak neonates.
  • Dogs and cats: usually sub-clinical.
  • Humans: abrupt onset fever and headache; 50% of cases radiographs show a patchy pneumonia, although physical chest signs are few. Illness is largely systemic. Mortality high in cases of pneumonia, hepatic infection, or endocarditis.
  • Complications and death are uncommon, although it may become severe and chronic with myocarditis, pericarditis or endocarditis.

Other Host Effects

  • May be latent until the stress associated with parturition; multiplication of the organism occurs in the birth tissue, urine and stool   →   environmental contamination.

Control

Control via chemotherapies

Vaccination

  • Not successful.

Diagnosis

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Nguyen S V, To H, Minamoto N et al (1997) Evaluation of the high-density agglutination test for Coxiella burnetii antibodies in animals. Clin Diagn Lab Immunol (6), 676-680 PubMed.
  • Willeberg P, Ruppanner R, Behymer D E et al (1980) Environmental exposure to Coxiella burnetii: a sero-epidemiologic survey among domestic animals. Am J Epidermol 111 (4), 437-443 PubMed.

Other sources of information

  • Hirsh D C & Zee Y C (1999) Eds. Veterinary Microbiology. Malden: Blackwell Science Inc. pp 291-293. ISBN 0 8654 2543 4.

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