Lack of serologic evidence of orthoflavivirus infection in dogs with meningoencephalitis of unknown origin and steroid-responsive meningitis-arteritis in the Netherlands.

The pathogenesis of meningoencephalomyelitis of unknown origin (MUO) and steroid-responsive meningitis-arteritis (SRMA) in dogs remains enigmatic. Numerous studies have attempted and failed to identify (viral) pathogens in samples from MUO- or SRMA-diagnosed dogs. Orthoflavivirus-associated meningoencephalitis or meningoencephalomyelitis has been diagnosed in dogs in several European countries. We investigated serologic evidence for orthoflavivirus infection in dogs with clinical diagnoses of MUO or SRMA in the Netherlands. Twelve dogs with a clinical diagnosis of MUO based on signalment, neurologic examination, MRI studies, CSF analysis, and response to treatment were included in the study (age range: 1-11 y; 4 females, 8 males; weight range: 8-44 kg). Serum samples from all 12 dogs tested negative in a commercial competitive ELISA and virus neutralization tests for West Nile virus, Usutu virus, and tick-borne encephalitis virus. We did not find serologic evidence of orthoflavivirus infection in dogs with MUO or SRMA in the Netherlands.