Syndromic surveillance of gastrointestinal illness using pharmacy over-the-counter sales. A retrospective study of waterborne outbreaks in Saskatchewan and Ontario.
OBJECTIVE
To ascertain if monitoring over-the-counter (OTC) drug sales could provide a timely syndromic surveillance method of detecting outbreaks of gastrointestinal illness.


METHODS
This study evaluated the potential of a syndromic surveillance system by comparing retrospective pharmacy OTC sales of anti-nauseants and anti-diarrheals to emergency room visits and case numbers from two Canadian outbreaks related to water contamination by Cryptosporidium, and E.coli O157:H7 and Campylobacter.


RESULTS
Local sales trends of weekly aggregate OTC products were comparable to the outbreak epidemic curves. Statistical control tests on the sales data indicated the start of the outbreak periods.


CONCLUSIONS
An automated monitoring tool based on spatial and temporal trend analyses of daily OTC sales would provide supplemental community health information for public health officials that is timelier than currently available laboratory-based surveillance systems.
Edge
Victoria L
VL
Health Canada, Guelph, Ontario. Victoria_Edge@hc-sc.gc.ca
Pollari
Frank
F
Lim
Gillian
G
Aramini
Jeff
J
Sockett
Paul
P
Martin
S Wayne
SW
Wilson
Jeff
J
Ellis
Andrea
A
D000930:Antidiarrheals / Q000627:therapeutic use*; D000932:Antiemetics / Q000627:therapeutic use*; D002169:Campylobacter Infections / Q000453:epidemiology*; D003430:Cross-Sectional Studies; D003457:Cryptosporidiosis / Q000453:epidemiology*; D003625:Data Collection / Q000379:methods; D004196:Disease Outbreaks; D004927:Escherichia coli Infections / Q000453:epidemiology*; D019453:Escherichia coli O157 / Q000472:pathogenicity*; D005767:Gastrointestinal Diseases / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology; D006801:Humans; D004366:Nonprescription Drugs / Q000627:therapeutic use*; D009864:Ontario / Q000453:epidemiology; D011159:Population Surveillance / Q000379:methods*; D012525:Saskatchewan / Q000453:epidemiology
D000930:Antidiarrheals; D000932:Antiemetics; D004366:Nonprescription Drugs