The long-term goal of this research is to understand the molecular genetics of breed specific necrotizing meningoencephalitis in the Pug (Pug Dog Encephalitis, or PDE). Although the cause of PDE is currently unknown, the breed predilection strongly suggests a genetic component. A necessary resource for this goal is detailed information regarding the incidence and inheritance of PDE, as well as extensive biological sampling and detailed medical histories. To this end, collected biological samples, detailed medical histories, and pedigrees have been used to create the largest information database currently in existence for PDE. Through whole genome scans, the investigators will work to identify a specific region of the genome that may be involved in PDE. These scans will survey the entire canine genome for areas potentially associated with PDE. Once candidate regions are identified, the investigators will narrow the region to a specific gene that may be causing PDE, eventually leading to the development of carrier detection tests.