What is the most likely natural method of human exposure to and acquisition of Q fever infections?

• A. Aerosol contact with C. burnetii-infected animals or animal remains
• B. Ingestion of contaminated water
• C. Direct person-to-person transmission
• D. Skin contact with infected meat

Answer: (A)

Q fever is most often acquired through inhalation of aerosols contaminated with Coxiella burnetii from infected animals or their birth products. The bacteria are shed in large numbers in birth fluids, urine, feces, and milk, and they can become airborne via dust, allowing infection even with limited contact or distance from animals. Ingestion of contaminated water is not the typical route, and direct person-to-person transmission is exceedingly rare. Skin contact with infected meat isn’t a recognized transmission pathway either. So, the common natural exposure is breathing in contaminated aerosols from animals or their remains, especially around birthing events or handling birth products.