<prompt> Which of the following infection is mainly diagnosed by serological tests?ActinomycosisQ FeverTBLeprosy  <response>: Ans. is b i.e., Q fever The diagnosis of actinomycosis is most commonly made by microscopic identification of sulphur granules. In most instances, the diagnosis of Q-fever relies upon serology. TB is usually diagnosed by sputom microscopy andor culture. Leprosy is diagnosed clinically which is confirmed by histological examination of skin biopsies and by the detection of acid fast bacilli in nasal discharges, scraping from nasal mucosa and slit-skin smear. 