Interactive GIS in Veterinary Epidemiology Technology & Application in a Veterinary Diagnostic Lab Basics GIS = Geographic Information System A GIS integrates hardware, software and data for capturing, managing, analyzing, and displaying all forms of geographically referenced information. Jackie Smith, PhD, MSc, Dipl. AVES Epidemiology Section Head University of Kentucky Veterinary Diagnostic Laboratory GIS data represents real world objects Roads Land Use Elevation Waterways Etc. 2 very broad methods Vector data model Raster data model 1 2 Today GIS Is Very Valuable to Government Used in Many Integrated Applications GIS Technology is Changing - Becoming Internet Focused Richer, Easier & More Pervasive New Styles, Patterns & Techniques Conservation Science/Modeling Land Management Natural Crime Defense/Security Congestion Resources Pollution Water Agriculture/Forestry Business Efficiency Emergency Management Economic Recovery Energy Biodiversity Global Warming Human Health Oceans Land Use Population Education Logistics Energy Public Safety Development Urbanization Humanitarian Facility Relief Management National Security Environmental Protection Law Enforcement Improving Planning, Management and Decision Making... New Services Web Maps Web 2.0 Real-Time Geodata Data UGC Mashups Mobile Social Networks New Media... Providing Critical Infrastructure Many Opportunities for Spreading Geography Everywhere 3 GIS in China is A National Priority A fundamental part of their 5 year planning Strategy Human Health & Disease Control Disaster Response Transportation Topographic Mapping Urban Management Utilities Remote Sensing Land Information Systems Water Resources Virtual Cities 分享地理价值 1
Maps Lie Accept it and move on. Basics the Projection Never enough space to display everything Distances will never be extremely accurate Specific purpose of the map? It s up to the cartographer to decide what s important to show What may be important to the cartographer is not important to you Maps are used for Information Travel Propaganda Inflating a country s importance» Economically» Socially» Military Or maybe a special map Topographic Flight Etc. Don t believe me? Look at any map How do you represent a 3-D spherical, lumpy world into a flat 2-D piece of paper or picture? A map projection is a systematic transformation of latitudes and longitudes of locations on the surface of a sphere into locations on a plane. Map projections are necessary for creating maps Depending on the map purpose, some distortions are acceptable, some aren t. No limit for possible map projections 7 8 Projections The dubious MERCATOR Projections The Peters Projection 9 10 Mercator Comparison North America Albers Equal Area Conic Surveillance at UKVDL GIS Mapping the distribution of disease Temporal-spatial scan statistics Compare what we are currently seeing to what we have seen in other years during the same time frame and locations (county level) Local veterinarians UKVDL Pathologists 11 2
GIS build updates daily as cases are finalized Gives necropsy trend chart for equine (shown is 2016) General Information Available Publicly Click on any colored county Gives you a list Info: submitted date, necropsy, species, breed, age, and disease (FINAL DX), and county Statistical evaluation to determine outbreaks of disease SaTScan Public Domain Software Developed by Dr. Martin Kulldorff at Harvard Originally designed for disease outbreak detection Different Models Spatial Temporal only Temporal-Spatial Time Space Permutation Used in: Archaeology, astronomy, epidemiology, genetics, criminology and others. The ability to detect outbreaks early is important to minimize morbidity and mortality through timely implementation of disease prevention and control measures. Martin Kulldorf, Harvard Medical School Most detection methods are purely temporal Can detect outbreaks that affect all parts of a geographic region simultaneously May be late in detecting outbreaks that start locally. Space-time permutation scan statistic Millions of overlapping cylinders of variable size that define the scanning window Each cylinder is a potential cluster Cylinder height represents the number of days of health events considered for the scan Method iterates over all possible combinations of cylinder diameters and heights Cylinder diameter and heights are parameters that are set by the user from zero to a maximum value. 3
For each geographic location and size of the scanning window Observed cases Expected cases Calculated using only case data with assumption that the probability of a case being in z (location) given it was observed on d (d) is constant for all days Significance testing is by Poisson generalized likelihood ratio (PGLR) Monte Carlo hypothesis testing to mitigate problems of multiple comparisons The cylinder with the highest PGLR is the primary disease cluster A p-value of 0.001 would result in a false signal (false positive) every 2.7 years (999 days) Analyses can be performed for a specific time interval (moving window) week, month Modeling detects active clusters on the last day of the analysis Prospective or retrospective analysis Critical data set extracts General Information Available Publicly GIS & Cluster analysis Significant event? Response 4
Acknowledgments and Questions? Dr. Craig N. Carter, DVM, PhD Dr. Agricola Odoi, PhD Dr. Noah Cohen, DVM, PhD 5