For a special holiday treat, we’re going to explore two tales of salmonella disease detectives -- the first about Mary Mallon (“Typhoid Mary”) and the birth of the genre; and the second about a mysterious salmonella outbreak at Massachusetts General Hospital solved with the assistance of a very jolly patient. Along the way, we’ll talk about clinical epidemiology, the long-lasting influence of Berton Roueché, and the joys of being an internist!   You can sign up for the Digital Education conference at cmeregistration.hms.harvard.edu/digitaleducation.   Sources:   Buckle GC, Fischer Walker CL, and Black RE, Typhoid fever and paratyphoid fever: Systematic review to estimate global morbidity and mortality for 2010.J Glob Health. 2012 Jun; 2(1): 010401. Marineli F et al, Mary Mallon (1869-1938) and the history of typhoid fever.Ann Gastroenterol. 2013; 26(2): 132–134. Soper GA, The Curious Career of Typhoid Mary, read on May 10, 1939 before the Section of Historical and Cultural Medicine. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1911442/pdf/bullnyacadmed00595-0063.pdf Norrington B, Cochineal: A Little Insect Goes a Long Way, UCSB Geography.  Roueche B, The Santa Claus Culture, The New Yorker, Aug 27, 1971. Lang DJ et al, Carmine as a Source of Nosocomial Salmonellosis, NEJM. Apr 13, 1967.   You can buy Medical Detectives here: https://www.amazon.com/Medical-Detectives-Collection-Award-Winning-Investigative/dp/0452265886