Are animals infected with Coxiella burnetii usually symptomatic?

• A. Yes
• B. No
• C. Rarely
• D. Only in some species

Answer: (B)

Infections with Coxiella burnetii in animals are usually asymptomatic. Many animals carry the bacteria without showing illness, even though they can shed large quantities of the organism in birth products, urine, milk, and feces. This shedding is the main route by which the agent spreads in herds and into the environment, and it creates a risk to humans through inhalation of contaminated aerosols.

Clinical disease does occur, but tends to be relatively rare across most species. When it does appear, the most common sign is abortion or production of weak or stillborn offspring, especially in sheep and goats during late gestation, with abortions also reported in cattle less frequently. Despite these exceptions, the typical situation is an infection without noticeable illness, which is why the correct answer is that animals are usually asymptomatic.