show Abstracthide AbstractMeningoencephalitis of unknown origin (MUO) describes a group of meningoencephalitides in dogs and cats with a hitherto unknown trigger. It is postulated that a known or unknown pathogen might be associated with the initiation and/or progression of this disease. In this study, we have performed next generation sequencing and analysis on fresh-frozen cerebrospinal fluid samples of six dogs with MUO in the acute phase of the disease.