Poster: USE OF A GEOGRAPHIC INFORMATION SYSTEM TO EXAMINE SPATIAL PATTERNS IN MARYLAND FOODNET DATA
 
Laura Hungerford, Michael McGuire, Carolyn Poppell, Karen T.Cuenco, Jessie Tighe, Melanie Megginson, Pat Ryan

 
PURPOSE: To develop a georeferenced database of bacterial foodborne disease in Maryland and to examine spatial aspects of disease occurrence overall, for specific pathogens, and for antimicrobial resistant Salmonella isolates.
 
METHODS: Latitude and longitude were determined for foodborne disease cases from the 2000 and 2001 Maryland FoodNet dataset using addresses. For a subset of 100 Salmonella cases, antimicrobial sensitivity data were also available. Location and case attributes were incorporated into an existing GIS that contained extensive environmental, hydrologic, and land use data. A population density surface was computed using 2000 US Census data (STF 1) and cases were mapped on this surface. Getis-Ord statistics were used to compare clustering of resistant isolates to all Salmonella cases with antimicrobial sensitivity data.
 
RESULTS: The 2148 cases were predominately Salmonella (1145) but also included Campylobacter (524), Cryptosporidia (42), E. coli (45), Listeria (34), Shigella (308), Vibrio (26) and Yersinia (24). These cases represented a catchment area of 7 counties and Baltimore City. Case distribution generally followed population distribution; however, clusters of cases were noted for several pathogens. Resistant isolates were not significantly more clustered within the distribution of all tested Salmonella cases.
 
CONCLUSION: Surveillance data constitute a unique resource for monitoring population health and for more in-depth analyses to uncover risk factors and develop interventions. Mapping the distribution of disease, demographics and environmental factors can provide insights for both processes. GIS allows epidemiologists to move from visual to quantitative statistical assessment of patterns and risk factors.