Researchers in England have developed a map that shows the distribution of sexually transmitted disease 'hotspots' throughout London. The map, compiled from information collected by the British government, will help healthcare workers target the areas that need the most help in preventing and treating diseases like genital warts, Chlamydia and AIDS.

With the number STD cases in London rising steadily since the mid-1990s, these infections have become a major public health concern and healthcare workers are keen to arrest the spread of these diseases.

Figures published recently by the British government show that in 2003 the Camden Primary Care Trust had the highest rate of STD infections in London, with the capital accounting for almost one third of all STD cases in England.

Though the table presents all of the requested data, it remains very difficult for the reader to fully appreciate the patterns and trends buried in them, or make quick and effective comparisons between the figures for different Primary Care Trusts or between the seven data sets for the years 1997 to 2003.

In addition, New York City health officials recently identified a man who had contracted a rare, highly drug-resistant strain of HIV, and states are beginning to develop disease surveillance systems that will help them deal with disease epidemics resulting from natural disasters and bioterrorism threats, according a study by the Center for Digital Government.

"States that utilize technology will be better equipped to react and respond to an outbreak, whether it's a disease or a bioterrorism event," Mark Struckman, vice president for research at the Center for Digital Government concluded in the white paper "Tracking Silent Killers" explaining the conclusions of the center's study.

Enter geographic information systems, which allow public officials to assemble collected information on a particular topic such as diseases, population density, crime or the location of a fire, enter it into a computer and create a map that shows the distribution of the information and makes it more useful.

"Looking for patterns, trends and comparisons in this kind data is crucial for decision makers seeking to tackle public health issues," said Dr. Maged Boulos, the lecturer in healthcare informatics in the University of Bath's School for Health, who developed the map in collaboration with Chris Russell and Michael Smith from Graphical Data Capture Ltd.

The interactive map, which shows the distribution of STDs in London Primary Care Trusts (PCTs) from 1997-2003, is available online. The map was created by merging a map of London PCTs with a spreadsheet containing STD information released by the British government using MapInfo Professional. The merged data was then imported into GeoReveal which was used to create the interactive map in the Scalable Vector Graphics (SVG) file format.

This format, unlike bitmapped graphics such as JPEGs and GIFs, allows images to be displayed at any size depending on the size of the browser in which they are viewed. Because SVG graphics are described using mathematical formulas, changing the size of the image doesn't hurt its quality. In addition, SVG files are smaller than the same image in the JPEG or GIF format.

When combined with other data sources and maps, such as demographic, deprivation or social exclusion, transport and existing genito-urinary medicine clinic data sets, the new map could help ministers and public health officials channel their resources and target STD prevention programs to the areas with the most need, or scale such programs according to the magnitude of the problem in different areas.

Viewing SVG graphics requires free SVG viewing software.

Additional Resources:
"Web GIS in practice II: Interactive SVG maps of diagnoses of sexually transmitted diseases by Primary Care Trust in London, 1997 -- 2003".