This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
Isolation period of an infection is impoant to control its spread. What is TRUE about isolation period of enteric fever? 
Select and explain. 
A. Till three bacteriologically negative stools and urine repos, B. Upto three days after staing the treatment, C. Till the fever subsides, D. Till Widal becomes negative
A: Till three bacteriologically negative stools and urine repos
Answer: A: Till three bacteriologically negative stools and urine repos 
Explanation: 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: Park's Textbook of Preventive and Social medicine, 19th edition, Page 196.