A farmer rearing sheep, presented with complaints of fever and weakness for the last one month. There is generalised lymphadenopathy. There was also associated hepatomegaly. Biopsy of liver showed non-caseating granuloma. There are most likely due to infection with:

Ans. is 'd' i.e., Brucella melitensis(Ref: Harrison, 19th/e, p. 1066 and Ananthanarayan, 9th/e, p. 339)Most common focal feature of brucellosis is musculoskeletal pain.Classic triad of fever - Profuse night sweating, arthralgia/arthritis and Hepatosplenomegaly are present in most patients.History of contact with animal followed by fever, lymphadenopathy and formation of non-caseating granuloma are features of brucellosis.