Q fever

Last updated: June 2, 2021

Summarytoggle arrow icon

Q fever is a notifiable zoonotic disease caused by Coxiella burnetii. Infection can occur directly (without a vector) or via vector transmission (e.g., inhalation of aerosols). There are 2 types of Q fever, acute and chronic Q fever. Acute Q fever occurs 2–6 weeks after infection and manifests mainly with flu-like symptoms and possibly atypical pneumonia and/or hepatitis. Chronic Q fever occurs months to years after infection and manifests with low-grade fever and often endocarditis. The best initial test for both, acute and chronic Q fever, is indirect fluorescent antibody test (IFA). Treatment for acute Q fever includes doxycycline and for chronic Q fever doxycycline PLUS hydroxychloroquine.

Epidemiologytoggle arrow icon

Epidemiological data refers to the US, unless otherwise specified.

Etiologytoggle arrow icon


  • Coxiella burnetii (gram-negative, intracellular)
    • Morphological similarities to Rickettsia
    • Can survive in harsh environments in a spore-like form

Route of transmission

  • Direct infection (no vector transmission)
  • Vector transmission: primary reservoir are cattle, sheep, and goats
    • Inhalation of spore-containing aerosols from the amniotic fluid or secretions of infected livestock
    • Ingestion of raw milk produced by infected animals

Risk groups

  • Slaughterhouse workers, farmers, shepherds, veterinarians

Pathophysiologytoggle arrow icon

Acute Q fever vs. chronic Q fevertoggle arrow icon

Types of Q fever
Acute Q fever Chronic Q fever
Incubation period [3]
  • 2–6 weeks
  • Months to years
Clinical features
Diagnostics Serology via IFA (best initial test)
Additional findings

Preventiontoggle arrow icon

  • Avoid consumption of unpasteurized milk products

Referencestoggle arrow icon

  1. CDC - Travelers' Health. Updated: June 24, 2019. Accessed: November 17, 2020.
  2. CDC - Q fever. Updated: June 27, 2019. Accessed: November 17, 2020.
  3. Leone M, Honstettre A, Lepidi H, et al. Effect of Sex onCoxiella burnetiiInfection: Protective Role of 17β‐Estradiol. J Infect Dis. 2004; 189 (2): p.339-345.doi: 10.1086/380798 . | Open in Read by QxMD

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