Electron microscopic diagnosis of human flavivirus encephalitis: use of confocal microscopy as an aid.

Journal Article

The distinction between intracranial viral infections and inflammatory conditions requiring immunosuppression is important. Although specific laboratory reagents are readily available for some viruses, diagnosis of arbovirus infection is more difficult. Transmission electron microscopy (TEM) theoretically allows identification of viral particles independent of reagent availability, but it has limited sensitivity. We report two cases of human flavivirus encephalitis diagnosed by TEM. Laser scanning confocal microscopy (LSCM) was used in one case to survey unembedded tissue slices for focal abnormalities, from which fragments smaller than 1 mm2 were excised for epoxy embedding. This facilitated TEM identification of intracytoplasmic, budding, 35-40 nm spherical virus particles, confirmed by serology as St. Louis encephalitis. In contrast to mosquitoes and newborn mice, in which high viral loads are associated with minimal tissue responses, these biopsies showed florid angiodestructive inflammation and microgliosis, with rare virions in necrotic perivascular cells and astrocytes. To our knowledge, this represents the first ultrastructural study of St. Louis encephalitis in humans, indicating the potential value of LSCM-aided TEM.

Full Text

Duke Authors

Cited Authors

  • Chu, CT; Howell, DN; Morgenlander, JC; Hulette, CM; McLendon, RE; Miller, SE

Published Date

  • October 1999

Published In

Volume / Issue

  • 23 / 10

Start / End Page

  • 1217 - 1226

PubMed ID

  • 10524522

International Standard Serial Number (ISSN)

  • 0147-5185

Language

  • eng

Conference Location

  • United States