Pennsylvania Combats West Nile Virus with ArcPad, Internet

Esri Services logoThe Commonwealth of Pennsylvania is working with Esri to develop and implement a system designed to combat the spread of West Nile virus.

Pennsylvania's Department of Environmental Protection (DEP), Department of Health (DOH), and Department of Agriculture (PDA) are collaborating with each other and the Esri Professional Services Division to build a West Nile Virus Internet map showing sample site locations in Pennsylvania.Surveillance System with ArcPad and ArcIMS. The surveillance system was designed to permit the storage and collection of the various field and lab data that is generated and collected by the three agencies. The objective is to make data immediately available to the staff that collects the data, the key decision makers, and the public so the spread of the virus can be tracked and appropriate decisions can be made.

At right: Internet map showing sample site locations in Pennsylvania.


West Nile virus first appeared in the United States in 1999 on Long Island in New York. Since then it has spread to other counties in Vermont, New Hampshire, Massachusetts, Connecticut, New York, New Jersey, Maryland, Rhode Island, Virginia, North Carolina, and Pennsylvania.

mosquito larvaWest Nile virus is one of many viruses trans-mitted by mosquitoes. The virus is spread when infected mosquitoes bite birds and other mammals. Infected birds fly to a new area and die from the virus; dead birds infected with the virus are one of the first indicators of the virus in an area.

To combat the disease in Pennsylvania, once infected dead birds or mosquitoes are found surveillance in an area increases. The enhanced surveillance information directs control efforts.

Pennsylvania System Description

Pennsylvania realized the importance of tracking all of the West Nile virus information spatially and chose to use GIS as the central repository for the data, which includes the results of the analysis of samples taken from sentinel chickens and horses, human beings, dead birds, and mosquitoes. Since the computer equipment and collection bottles set up on car hood to use ArcPad in the fieldsamples must be sent to a laboratory to be analyzed, the locations where the samples were taken must be recorded in case virus control measures must be instituted. To eliminate the delay associated with interpreting and compiling handwritten notes, Pennsylvania chose to use ArcPad software loaded on handheld Compaq Aero computers to record the location and other sample information. Staff members in the field use ArcPad to specify sample locations on a map and enter the other sample information on forms designed for this purpose.

Above right: Using ArcPad in the field. Inset: Mosquitoes are collected in traps.

One of the most important of the various pieces of information is an ID number. A unique number is entered on each form. The bottle that contains the sample is labeled with the same number so that all the information about a sample can be kept together in the database.

An internal Web server automatically checks the external database and retrieves any new data. Data approved for public release (e.g., summary statistics by county) is published on the Internet; see

Current Status and Future Plans

As of October 2000, Phase I of the project, which focused primarily on designing and implementing the data collection software and hardware and analyzing and tracking mosquito samples, is nearing completion; the hardware and software for the system have been installed, and the ArcPad and Web user interfaces have been designed. Thirty-one mosquito pools and 29 dead birds have tested positive for the virus as of October 31, 2000.

During Phase II, the system will be refined and expanded. Specifically, ArcPad will be used to report locations and other data for blood samples taken at random from wild birds. Web-based forms with attached drop-down lists of locations will be used to record blood sample data for sentinel chickens and horses, and address geocoding software accessed from a Web interface will be used to determine the locations of infected humans and animals.

This system demonstrates the potential of handheld technology for disease monitoring and control. Eric Conrad at the Office of Field Operations at DEP, which is leading the project, says, "The handheld units enabled timely collection of field data. Web applications enable data submittal from various State and local agencies, and Esri software provided a vehicle for displaying the data from the database for both information dissemination and management decision making. Because of the versatility of Esri software, the data could be displayed at varying levels of detail: general for the public, moderately detailed for State and county agencies interested in what was going on, and highly detailed for management decisions."

For more information, please visit or contact Eric Conrad, Pennsylvania Department of Environmental Protection (e-mail:

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