933Outbreak investigation of canine acquired idiopathic megaoesophagus in Australia, 2017-2018

Background VetCompass Australia collects de-identified data from primary-care, companion animal practices across Australia, providing a large, representative database. VetCompass data were used to investigate an outbreak of megaoesophagus in dogs in Australia in 2017/2018. A specific proprietary dogfood was hypothesized as the cause. Methods The instantaneous daily hazard of megaoesophagus for the period January 2012 to February 2018 was plotted using survival analyses. A case-control study focused on dog demographics and management practices was performed to determine risk factors for megaoesophagus. Results There was a 7-fold increase in the incidence rate of canine megaoesophagus from 2014 (0.11 [95% CI 0.02 to 0.58] cases per 100,000 dogs per day) to 2018 (0.82 [95% CI 0.19 to 4.2] cases per 100,000 dogs per day) with greater numbers diagnosed during summer months of the year. The odds of feeding one specific dry dogfood was 325 (95% CI 64 to 1644) times greater for cases, compared with controls. Conclusions Evidence obtained through this study strongly suggests that a specific dogfood was responsible for most cases. The food was recalled prior to completion of this research. Further investigation into incidence rates and seasonal patterns of canine megaoesophagus are ongoing. Key messages Use of aggregated, de-identified data collected across small animal practices in Australia allowed identification of trends and seasonal patterns of a rare disease in dogs for the first time and provides opportunity for surveillance of this and other companion animal diseases.