Fig 1.
Graphic depiction of ArcGIS linear directional mean function.
The ArcGIS linear directional mean function converts the mean daily vectors for direction and distance of virus spread (left) into a single vector that indicates the mean direction and mean distance of virus spread over time.
Fig 2.
Epidemic curve for a Spring 2013 porcine epidemic diarrhea virus (PEDv) outbreak in 4 contiguous U.S. States.
Several peaks occurred, as expected with a propagated outbreak.
Table 1.
Porcine epidemic diarrhea virus (PEDv) site-level incidence during a Spring 2013 outbreak in 4 contiguous U.S. States, by Swine Company.
Table 2.
Porcine epidemic diarrhea virus (PEDv) site-level status during a Spring 2013 outbreak in 4 contiguous U.S. States, by production type.
Fig 3.
Hotspot cluster analysis of a Spring 2013 porcine epidemic diarrhea virus (PEDv) outbreak in 4 contiguous U.S. States.
The red shades show the core cluster, which measured about 33 miles in the north-south direction and 41 miles in the west-east direction.
Fig 4.
Weekly directional ellipses showing an overall north-south orientation of virus spread.
No ellipse was generated for the first week because only one positive was reported that week. During the third week, an outlying positive in the southeastern extent of the outbreak caused a northwest to southeast orientation.
Fig 5.
Direction of wind and disease spread during a Spring 2013 porcine epidemic diarrhea virus (PEDv) outbreak.
The box on the upper right side of the figure summarizes wind data for the entire outbreak period, and the left side of the figure summarizes results from the linear directional-mean analysis for the direction of disease spread. On the left side, each colored circle represents the mean geographic center for all incident cases on a given day. The blue circles are earlier dates in the outbreak, and the red circles are later dates in the outbreak. The gray squares show locations of sites that remained negative for PEDv; each square measures 5 by 5 miles. Squares with a darker gray color have more negative sites in the area. The black arrow on the left side is the overall direction of disease spread from the linear directional-mean analysis. The mean direction of spread during the entire outbreak was south at 184.2 degrees (measured clockwise from due north), and the mean distance of spread was 19.3 miles.
Fig 6.
Geographic distribution of swine farms in the study in relation to the first case during a Spring 2013 outbreak of porcine epidemic diarrhea virus (PEDv).
More than three-fourths of sites are south of the index case (indicated by red star), with 60 percent in the path of primary wind direction.