In 1937,a man employed to lay water pipes in Croyden, England, was found to be the source of severe epidemic of typhoid fever. T heman , an asymptomatic carrier of SALMONELLA ENTERICA serotype Typhi, the bacterium that causes typhoi, habitually urinated at his job site. In this process, he contaminated the town's water supply with bacteria from his bladder. Over 300 cases of typhoid fever developed ,and 43 people died before man was identified as the carrier.

a. How do you think health officials were able to indentify the source of this typhoid epidemic?
b. Given that antibiotics were not generally avalible in 1937,how could health officials end the epidemic short of removing the man from the job site