Q fever — DTM&H MCQ

Correct answer: B — Q fever

Q fever (B) is correct because Coxiella burnetii is transmitted through inhalation of aerosols and dust contaminated by parturition fluids, placenta and birth products of infected ruminants, making abattoir workers and those assisting goat births at particularly high risk. It classically causes a nonspecific febrile illness with severe headache and atypical (often patchy or bilateral) pneumonia, and unlike many rickettsial infections there is characteristically no rash. This combination of occupational exposure to parturient goats, headache and pneumonia without rash is the textbook presentation used to distinguish Q fever from the other zoonoses on this list. Why the other options are wrong: E. Legionellosis: causes atypical pneumonia but the source is contaminated water systems (air conditioning, showers, spa pools), not animal parturition, and there is no epidemiological link to abattoir or livestock work. A. Psittacosis: caused by Chlamydia psittaci and linked to exposure to birds (parrots, pigeons, poultry), not goats, so the occupational history does not fit. D. Scrub typhus: transmitted by trombiculid mite (chigger) bites in scrub vegetation and almost always produces an eschar and often a rash, which is explicitly absent here. C. Brucellosis: also linked to goats and unpasteurised dairy, but presents with prolonged undulant fever, arthralgia, hepatosplenomegaly and orchitis rather than atypical pneumonia, which is the dominant feature in this stem. Key point: occupational exposure to birthing ruminants plus headache, atypical pneumonia and absence of rash points to Q fever (Coxiella burnetii), transmitted by inhalation of aerosolised birth products.

Reference: UK Health Security Agency (formerly Public Health England), 'Q fever: guidance, data and analysis', gov.uk, https://www.gov.uk/guidance/q-fever