Virus chloropleth
This map shows state-level surveillance data for West Nile virus and Zika virus infections across the United States. It uses a color-coded choropleth to distinguish total case counts per state, with tooltips revealing detailed figures for neuroinvasive and non-neuroinvasive disease cases, deaths, and presumptive viremic blood donors. Built with D3 v3 and rendered as SVG, the visualization encodes magnitude through graduated fill colors. Users can toggle between datasets for West Nile virus (2015 and 2016) and Zika virus (2015). The map was adapted from prior blocks by Michelle Chandra, Scott Murray, and others, with sources and code publicly available. It serves as an educational resource for the "Bugs to Barcodes" project at James Madison University.