A research team at the Swedish Institute for Infectious Disease Control, recently published data showing that queries for *vomit* (asterisks denote any prefix or suffix) submitted to the search engine on a medical website in Sweden (www.vardguiden.se), match the number of laboratory-verified cases almost perfectly (see figure).
Figure. Number of queries for *vomit* submitted to a medical Web site (blue), number of laboratory-verified norovirus samples (red), with baselines and 99% prediction intervals, and number of media articles about winter vomiting disease (black) in Sweden, 2005–2010. From: Hulth A, Andersson Y, Hedlund K-O, Andersson M. Eye-opening approach to norovirus surveillance [letter]. Emerg Infect Dis. 2010 Aug: http://www.cdc.gov/EID/content/16/8/1319.htm
The original article in Emerging Infectious Diseases can be found here.