Which of the following does not involve a bacterial exotoxin?
diphtheria
whooping cough
scarlet fever
q fever

Option D. "Q fever"

Explanation:

Q fever, the zoonotic disease is caused by a bacteria rickettsia, Coxiella burnetii. The major cause of this bacterial disease is domestic livestock such as, sheep, goats and cattle.

In humans, the primary route of Q fever is through inhalation of contaminated farmyard aerosols. Symptoms with acute Q fever involves pneumonia, high fever, coughing, headache, and general malaise.

Hence, the correct option is D.