<prompt> Isolation period of an infection is impoant to control its spread. What is TRUE about isolation period of enteric fever?Till three bacteriologically negative stools and urine reposUpto three days after staing the treatmentTill the fever subsidesTill Widal becomes negative  <response>: Since typhoid fever is infectious and has a prolonged course, the cases are better transferred to a hospital for proper treatment, as well as to prevent the spread of infection. As a rule, cases should be isolated till three bacteriologically negative stools and urine repos, are obtained on three separate days. Ref: Parks Textbook of Preventive and Social medicine, 19th edition, Page 196. 