We conducted retrospective testing of clinical samples submitted to veterinary diagnostic laboratories for porcine deltacoronavirus.

Over 2000 samples were tested over three separate years with 3 positive samples detected prior to the PDCoV outbreak detection in February 2014.

We surveyed 42 early infected swine farms to determine various farm level characteristics, descriptive estimates of biosecurity practices and disease status over time of each operation.

Clinical signs of PDCoV were reported to be similar to those of PEDv. The average number of animals on each operation exhibiting clinical signs (morbidity) and the average number of case fatalities was greatest for suckling and weaned pigs.

The survey included questions regarding biosecurity practices for visitors and operation employees; trucks, equipment and drivers; and feed sources. These questions attempted to identify a likely pathway of introduction of PDCoV onto the operations surveyed.