___________% of acute Q fever cases are asymptomatic

• A. 25%
• B. 50%
• C. 75%
• D. 90%

Answer: (B)

A large share of acute Q fever infections are asymptomatic. In many studies, about half of people who acquire Coxiella burnetii infection do not develop noticeable illness, while the rest have symptoms ranging from mild fever and malaise to pneumonia or hepatitis. This reflects the broad clinical spectrum of Q fever and helps explain why many exposures are never recognized clinically.

Seroprevalence surveys and outbreak investigations show that the true number of infections is higher than the number of clinically diagnosed cases, because asymptomatic infections don’t prompt medical care. The 50% figure sits in the middle of reported ranges—not as low as a quarter, and not as high as three-quarters or more in most settings—making it a reasonable common estimate across populations.