Virus Entry to the Brain and the Blood-Brain Barrier (BBB)

Vocabulary flashcards covering concepts related to how viruses can access the brain beyond neural spread, including the blood-brain barrier and alternative routes.

Blood-brain barrier (BBB)

A selective barrier formed by brain microvasculature endothelial cells with tight junctions that restricts the passage of most substances and pathogens from the bloodstream into the CNS.

Axonal (neural) spread

Viral movement along neurons to reach the CNS, often via retrograde transport from peripheral nerves.

Hematogenous spread

Virus reaching the brain through the bloodstream, which may involve crossing or affecting the BBB.

Transcytosis across the BBB

Endothelial cells transport virus-containing vesicles from the blood to the brain side, sometimes via receptor-mediated or adsorptive mechanisms.

Trojan horse mechanism

Virus hides inside infected leukocytes that cross the BBB, delivering the virus into the CNS.

Olfactory route

Entry into the CNS via the olfactory nerve/bulb after infection of the nasal/olfactory epithelium, potentially bypassing mature BBB.

Circumventricular organs

Brain regions with fenestrated or leaky capillaries lacking a typical BBB, which can permit pathogen entry into the CNS.

Choroid plexus route

Viral access to the CNS via CSF production areas where barriers may allow entry into the CNS.

Endothelial infection and barrier disruption

Virus infects brain endothelial cells or disrupts tight junctions, increasing BBB permeability and enabling CNS entry.