Salmonella typhi is the causative agent of typhoid fever. The infective dose of S.typhi -: (A) One bacillus, (B) 108 - 1010 bacilli, (C) 102 - 105 bacilli, (D) 1 - 10 bacilli
Answer is C. All Salmonella infections begin with ingestion of organisms, most commonly in contaminated food or water. The infectious dose is 103–106 colony-forming units.