<prompt> The most common mode of transmission of brucella isDirect contactIngestion of raw milkAir borneMan to man  <response>: The organism from the infected animal enters the human body by direct contact. Through the wound, the conjunctiva, by inhalation or by ingestion of products from infected animals. The incubation period is usually about 10-30 days, but may sometimes be very prolonged. Ref: Textbook of microbiology; Ananthanarayana and panikers; 10th edition; Pg: 346 