Final answer:
The rabies virus travels to the CNS using retrograde flow, reaching the CNS through spinal ganglia, and leading to encephalitis by disrupting neurotransmitter function.
Step-by-step explanation:
The rabies virus can travel to the central nervous system (CNS) via retrograde flow. This mechanism involves the virus moving from the site of the bite into motor and sensory axons of peripheral nerves. The virus employs retrograde transport, which allows it to spread from nerve to nerve, eventually reaching the CNS through the spinal ganglia. Once in the CNS, rabies virus leads to encephalitis, causing symptoms associated with the disease by disrupting normal neurotransmitter function. This virus acts neurotoxically by competing with neurotransmitters for receptor sites like acetylcholine, GABA, and glycine receptors. Aside from harming the nervous system, once the rabies virus reaches and infects the brain, it can exit the CNS and spread to other bodily tissues, like the salivary glands, releasing more virus into the saliva.