Which of the following infection is mainly diagnosed by serological tests?

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 and/or 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.