There are several ways for neuropathogens to get into the brain. These include retrograde axonal transport along motor and olfactory neurons, hematogenous spread across the blood-brain barrier (BBB), the blood-cSF barrier, the meningeal-cSF barrier, and direct infection of endothelial cells or infected leukocytes crossing the BBB . Viruses infect axon terminals from the mucosal epithelium (ME) and disseminate to sensory neurons and autonomic neurons (SN). Retrograde axonal transport facilitates the viral infection of the spinal cord . Virus-infected leukocytes infiltrate the central nervous system through the blood-brain barrier (BBB), microvascular endothelial cells, and peripheral nerves. They then discharge from the central nervous system (CNS) to the central lymph nodes (CLN) via meningeal lymphatic vessels (MLVs) . In viral encephalitis, when microglia and T cells don't work together properly, it can change how microglia eat neuronal synapses, which can lead to problems with brain function .