Brucella is transmitted by all of the following, EXCEPT:

Usual transmission of brucella is from infected animals to man. Man to man transmission is not known. Most commonly, infection occurs from direct contact with infected tissues especially placenta. Ingesting infected food and inhaling aerosolised bacteria are established modes of transmission of brucella. Ref: Textbook of Preventive and Social Medicine, Park, 20th Edition, Chapter 5, Page 253.