Disease investigations for equine infectious anemia in Canada (2009-2012) - Retrospective evaluation and risk factor analysis.

This retrospective study describes the detection of equine infectious anemia (EIA) during Canadian Food Inspection Agency (CFIA) disease investigations in Canada, examines aspects of importance for disease control, and evaluates potential animal-level risk factors for EIA in high-risk horses. Based on review of all EIA-positive samples and all samples collected during disease investigations (N = 4553) over a 4-year period (2009 to 2012), 409 EIA cases were detected. Horse owners with EIA cases owned between 1 and 60 affected animals, and 49 horses seroconverted during a disease investigation period. Twenty-nine percent of cases ( = 68) for which this information was available had, or possibly had, clinical signs of EIA. Using a mixed effects logistic regression model, horses in older age groups were at greater odds of having a positive EIA status. The study emphasizes the importance of disease investigation activities when EIA is detected and identifies age as an animal-level risk factor in high-risk horses.