Microbiology General e0c1998a Infective dose of salmonella typhi ? A 10 bacilli B 1000 bacilli C 103-106 bacilli D 1010 - 1012 bacilli High-Yield Explanation Ans. is 'c' i.e., 103-106 bacilli In human volunteer experiments, the infective dose was found to be 103-106 bacilli.