Table 1.
Viral and prion infections in CNS-associated infections in Brazil.
| Genus/Causative Agents | Structure | Transmission | Route to Brain | Neurological Disorders | Types Commonly CNS-Associated Infections |
|---|---|---|---|---|---|
| Enterovirus | Single-stranded RNA Nonenveloped Icosahedral symmetry | Fecal–oral, respiratory | Infected endothelial cells; retrograde axonal transport; Trojan Horse within infected monocytes |
Aseptic meningitis, acute flaccid paralysis, encephalitis/meningoencephalitis | E6, E7, E11, E18, E30, CVB5, CVA2, EV-A71, CVB5, E6, E7, E11, CVA13, EV-C99, CVB2, E6, E18, E30 |
| Flavivirus | Single-stranded RNA Enveloped Icosahedral symmetry | Via arthropod vectors | Hematogenous; axonal transport; Trojan Horse within infected leukocytes | Encephalitis, microencephaly (Zika) | Dengue, Yellow fever, Zika |
| Alphavirus | Single-stranded RNA Enveloped Icosahedral symmetry | Via arthropod vectors | Anterograde axonal transport | Encephalitis | Chikungunya |
| Simplexvirus | Double-stranded DNA Enveloped Icosahedral symmetry | Oral-to-oral, oral–genital contact with sores | Primary infections: olfactory, hematogenous and genital (HSV-2), retrograde axonal transport Reactivation: from neurons trigeminal or sacral (HSV-2) ganglia, anterograde transport to reach CNS | Encephalitis, meningoencephalitis | HSV-1 HSV-2 |
| Varicellovirus | Double-stranded DNA Enveloped Icosahedral symmetry | Via droplets, aerosol, direct contact | Peripheral spread VZV- reactivation from sensory ganglia- central spread to brain or to temporal arteritis or to spinal cord arteries | Meningoencephalitis, myelitis, cranial neuropathies | VZV |
| Cytomegalovirus | Double-stranded DNA Enveloped Icosahedral symmetry | Contact with saliva or urine; sexual; contact breast milk; transplanted organs; blood transfusions | Hematopoietic cells monocytes—systemic spread- brain, spinal cord, meninges, nerve roots | Encephalitis, myelitis, polyradiculopathy, multifocal neuropathy | CMV |
| Prion scrapie | Beta structure enriched form of cellular prion protein | Iatrogenic, oral, blood | Infected epithelium, lymphoid tissues | Rapidly progressive cognitive impairment with behavioral and visual disturbances, ataxia, and myoclonus. | BSE, vCJD, iCJD |