Figure 3.

Spatio-temporal reconstruction of trade between zoos and private holdings with confirmed VSBV-1 positive squirrels. Timeline of squirrel presence and trading routes, including human cases and detection of VSBV-1-positive squirrels. Each horizontal line, differently coloured to illustrate the host species, represents the presence of at least one squirrel of that species at the named location over time. The vertical coloured lines indicate the trading route of one or more squirrels from one location to another at the distinct point in time. Squirrel holdings in zoos are shown in shaded areas. Filled red boxes on the coloured lines represent the quarter of the year in which one or more VSBV-1 positive squirrels were detected in the respective institution. Red frames mark the time period of reported neurological disease of proven, probable and possible human VSBV-1 encephalitis cases. Red arrows mark the assumed transfer of one or more infected squirrels. Streamlining was performed by omitting unaffected squirrels and holdings with no ties to affected animals and institutions, respectively. Affected holdings without reliable data were also not included.