Tracking the Polio Virus down the Congo River: A Case Study on the Use of Google Earth™ in Public Health Planning and Mapping

This paper explains, through the example of polio eradication activities in the Democratic Republic of Congo (DRC), the use of Google Earth™ (GE) as a planning tool and shares the methods used to generate public health maps for advocacy and training, as well as to help understand the relationship between the entities involved in the polio outbreak and response. As noted here, geographic information system (GIS) technology is increasingly used by public health professionals, policymakers, and other public health actors to better understand how geographic relationships affect disease transmission patterns, access to health care, and health outcomes.

In 2004, 54 cases of polio caused by wild polio virus type 1 (WPV1) were reported in 4 DRC provinces from February 2006 to December 2007. In response to this outbreak, mass immunisation campaigns, also known as Supplemental Immunisation Activities (SIA), were launched in an effort to interrupt the circulation of the virus and eliminate the risk of exportation. The geospatial distribution of polio cases showed that the outbreak seemed to follow the course of the Congo River. So, the overall objective of the "river strategy" was to stop the progression of WPV1 by ensuring that the entire eligible population living "on the river" was vaccinated against polio during the SIA.

The author describes, in step-by-step detail, the use of Keyhole Markup Language (KML), an XML-based language for expressing geographic annotation and visualisation on web-based, two-dimensional maps and three-dimensional Earth browsers like GE. The method described in this paper is applicable to all the current versions of GE. By following these steps, he and his colleagues in the DRC used GE in order to zoom in on sections of the Congo River, obtaining images of the river's corridor of acceptable resolution. "This improved view of the river, combined with the knowledge of local key informants, provided valuable information to better estimate distances, locate islands, and overall improve our knowledge of the topography."

In conclusion, "the overall result of using GE was a better allocation of resources (fuel, outboard engines, and canoes) and an improved dispatch of vaccination teams....Social mobilization activities as well as supervision and monitoring were also greatly improved. With these improved micro-plans, populations previously missed by routine immunization services were identified and vaccinated. Vaccination teams were posted on passage points to screen all embarkations for eligible children; ports and shore-markets were continuously surveyed 24 h[ours] a day for arriving and departing ships during the entire duration of the campaign."