[…] encephalitis is one of many mosquito-transmitted viral infections that may progress to acute inflammation of the brain parenchyma and meninges, which presents with confusion, somnolence
[semanticscholar.org]
2 and 6 days), then general depression, dullness, anorexia, stiffness, ataxia, hyperesthesia, aggression, excitability, continuous chewing movements, aimless wandering, somnolence
[vetstream.com]
[…] rare cases, WEEV infection may cause encephalitis or encephalomyelitis, resulting in neck stiffness, confusion, visual disturbances, photophobia, tonic-clonic seizures, somnolence
[msdsonline.com]