Contagion is the spread of disease from one person to another by close proximity or contact. A disease that can spread from person to person is said to be a contagious disease.
QUESTION
Bowel regularity means a bowel movement every day. See AnswerFrom 
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References
Jameson, J. Larry, et al. Harrison's Principles of Internal Medicine, 20th Ed. New York: McGraw-Hill Education, 2018.