Which of the following is a risk factor for chronic Q fever?

• A. Regular exercise
• B. Vegetarian diet
• C. Having a pet dog
• D. Age over 60 years

Answer: (D)

The main idea here is what makes someone more likely to develop chronic Q fever after an infection with Coxiella burnetii. Chronic Q fever most often shows up in people who already have damage or disease of the heart valves or blood vessels, or who are immunocompromised. As people age, these underlying conditions become more common, and the immune system also changes with age, making it harder to clear a persistent infection. That’s why older age, specifically over 60, is a risk factor for chronic Q fever.

Regular exercise, a vegetarian diet, and having a pet dog do not by themselves create the conditions that let Coxiella burnetii persist in the body. They aren’t linked to the kind of chronic infection risk seen with underlying heart or vascular disease or immune decline.