By Bridget M. Kuehn
Posted Jan. 1, 2005
Geographic information systems, which allow users to create layered maps of geographic, topographic, and industrial information, have been embraced by several states as a way to prepare for potential disease outbreaks, such as a foot-and-mouth disease outbreak. Now, researchers are studying potential regional and global disease-control applications for the technology.
A researcher from Cornell University and a team of researchers from the University of California-Davis presented some of their work on the regional and global applications of GIS technology in preventing and controlling FMD outbreaks, at the Conference of Research Workers in Animal Diseases, Nov. 14-16, 2004, in Chicago.
Dr. Timothy E. Carpenter, a professor and epidemiologist at UC-Davis, and Dr. Rebecca Garabed, a veterinarian and student in the master's of veterinary preventive medicine program at UC-Davis, presented two research papers that are part of a larger project to model FMD outbreaks at the global, national, and subnational level. The project is being funded, in part, by the Armed Forces Medical Intelligence Agency and the Department of Agriculture's Cooperative State Research, Education, and Extension Service.
"Some countries have eradicated the disease easily, while others have had some difficulties," Dr. Garabed said. She explained that many countries that have difficulties eradicating the disease lack the economic resources and the political ability to implement control measures.
So, she developed a GIS model, using indicators of political stability and economic strength, with data from the World Bank and the U.S. Central Intelligence Agency. Using the model, she tested whether there was a relationship between these factors and a country's FMD status, on the basis of the Office International des Epizooties' standards and FMD experts. The data cover the period between 1996 and 2002.
She found that though her model needed some refinement, there was a relationship between a country's FMD status and its political and economic stability. As would be expected, she also found a strong relationship between a country's FMD status and whether the country bordered a country that was not FMD-free.
One surprising finding was that there was a strong relationship between the country's FMD status and the extent to which citizens of the country are able to participate in the selection of their government, one of the World Bank's governance indicators. Dr. Garabed said this highlights the importance of considering unconventional factors that might impact a country's disease status.
The substantial increase in the interstate movement of animals since the last U.S. FMD outbreak, in 1929, suggests that if another outbreak were to occur in the United States, it would be a larger epizootic, Dr. Carpenter said. To prevent such an outbreak, it's important to be able to reliably and rapidly track interstate animal movements, he said. Unfortunately, most such data are being collected individually by states and are not available in a national database. Also, the quality of some of the data is questionable. Dr. Carpenter discussed the advantages of creating a GIS-based national program to monitor animal movement nationwide.
Dr. Ariel Rivas, a visiting research fellow at Cornell University, presented his examination of whether geo-referenced data could help countries develop a cost-effective, early intervention strategy for dealing with FMD outbreaks. To test the idea, Dr. Rivas examined geo-referenced data from the FMD outbreak in Uruguay in 2001. Dr. Rivas looked at four variables: the location and size of 4,022 land parcels, animal density, percentage of dairy farms per county, and road density. He found that region-specific control measures that take these variables, and possibly others, into account could be cost-effective and efficacious.