Q-225. Campylobacter and Salmonella Infections in Michigan: Evaluation of Seasonal and Geographic Trends in Reporting

T. J. M. Onifade, J. B. Kaneene;
Michigan State Univ., East Lansing, MI.

Campylobacteriosis and Salmonellosis are common gastrointestinal infectious diseases in the United States and world-wide. Given the high incidence and health burdens of these diseases, much research has been done and trends in incidence of these diseases (seasonal and geographic) have been reported, but not fully explained. This study aims to statistically evaluate the seasonal trend in case reporting by analyzing (for Michigan and its counties) the high reporting period, identifying the parameters peak-week, start and end-week, and duration for that period. This study also evaluates the relation of geographic location and county incidence with the high reporting period parameters. Historical case data on Campylobacter and Salmonella infections in Michigan (1992-2005) were evaluated and novel statistical techniques were applied to identify the high reporting period parameters. Linear modeling techniques were used to evaluate the relationships of geographic location and county incidence to disease reporting trends. The time series of reporting shows regular behavior with a period of high reporting for both campylobacteriosis and salmonellosis in the summer and early fall. This period varies between counties with respect to all parameters. The duration of the high reporting period was the only variable that was consistently associated with geographic location and incidence.