Visualizing the Spread of West Nile Virus

The West Nile Virus was rst recognized in the United States in 1999 as the cause of severe and fatal human illness in metropolitan New York City. Since 1999, the West Nile Virus has rapidly spread westward. By the end of 2002, there were only a few states in the Western United States where the virus had not been observed. However, indications are that the virus will be observed in every state of the contiguous United States by the end of 2003. The West Nile Virus transmission cycle involves di erent species of mosquitos and birds and can be deadly to humans, horses, birds, and other animals. In this paper, we visualize the spread and occurrence of the West Nile Virus and graphically relate these to various climatic and environmental conditions. Part of the data that is being presented originates from remote sensing satellites as well as from di erent medical centers. Our visual exploration is based on micromaps and standard choropleth maps.