The primary objective of this study was to evaluate risk factors for incidence cases of reported PCVAD. A time-matched case-control study was used as a study design approach, and conditional logistic regression as the analytical method. Briefly, 278 herds located in southern Ontario were included in this study initially using two different sampling mechanisms: (i) sampling of herds positive for porcine reproductive and respiratory syndrome virus (PRRSv) using data from a diagnostic laboratory (Animal Health Laboratory, University of Guelph, Guelph, ON, Canada), based on rtPCR-positive diagnostic findings, and (ii) sampling of PRRSv-negative herds, based on assessment of a herd veterinarian. Herds were classified into PCVAD-positive and negative herds on the basis of producers’ assessments, and results obtained during exploratory spatial analysis were used to guide the design of this case-control study. In conclusion, the spread of PCVAD due to high-risk local exposure was primarily driven by herd ownership. It was therefore impossible to distinguish local spread from common direct or indirect sources that contributed to the emergence of disease concurrently in different premises under the same ownership. Surprisingly, frequency of direct or indirect contacts did not differ between case and control herds. This also applies to frequency of feed delivery, which, although statistically significant, was driven by a single highly influential point, which in itself did not align with a biological rationale for spread through feed deliveries. Two risk factors that remained stable were herd PRRSv status and directional spread in a western direction.