Emerging viral infections of the central nervous system: part 2

Abstract

The first part of this review ended with a discussion of new niches for known viruses as illustrated by viral central nervous system (CNS) disease associated with organ transplant and the syndrome of human herpesvirus 6-associated posttransplant acute limbic encephalitis. In this part, we begin with a continuation of this theme, reviewing the association of JC virus-associated progressive multifocal leukoencephalopathy (PML) with novel immunomodulatory agents. This part then continues with emerging viral infections associated with importation of infected animals (monkeypox virus), then spread of vectors and enhanced vector competence (chikungunya virus [CHIK]), and novel viruses causing CNS infections including Nipah and Hendra viruses and bat lyssaviruses (BLV).

Figure 1

Magnetic resonance and autopsy findings in progressive multifocal leukoencephalopathy. A and B, Sagittal fast-spin echo inversion recovery magnetic resonance images taken 2 months apart showing rapidly progressing white matter lesion(s) predominantly in the left hemispheric white matter from a patient who developed progressive multifocal leukoencephalopathy following treatment with natalizumab. C, A coronal fast-spin echo magnetic resonance image showing the largest lesion in the left frontoparietal white matter. D, The corresponding large cavitary white matter lesion found at autopsy. Copyright 2005 Massachusetts Medical Society. All rights reserved.

Figure 2

Monkeypox virus infection. A, Hemorrhagic skin lesions in a patient with monkeypox virus infection. B, Fluid-attenuated inversion recovery magnetic resonance image showing areas of increased signal in the left thalamus (open star) and right posterior parietal cortex (solid star) from a patient with monkeypox encephalitis at day 3 after onset. Copyright 2004 by the Infectious Disease Society of America. All rights reserved.

Figure 3

Vectors and distribution of chikungunya virus. A and B, Aedes albopictus (A) and Aedes aegypti (B) are the principal vectors for transmission of chikungunya virus infection. Reprinted with permission from Elsevier. C, Worldwide distribution of A albopictus mosquitoes. Copyright 2007 Massachusetts Medical Society. All rights reserved.

Figure 4

Magnetic resonance and electron microscopy findings in Nipah virus. A, Axial fluid-attenuated inversion recovery magnetic resonance imaging in a patient with acute Nipah virus encephalitis showing multiple discrete hyperintense lesions in the white and gray matter. B, Axial fluid-attenuated inversion recovery magnetic resonance imaging of a patient with relapsed Nipah virus encephalitis showing confluent lesions involving primarily the cortical gray matter. Copyright 2000 Massachusetts Medical Society. All rights reserved. C, Ultrastructural characteristics of Nipah virus isolate in cell culture as seen by negative stain electron microscopy. A single nucleocapsid shows the typical herringbone appearance characteristic of the family Paramyxoviridae. Scale bar, 100 nm. Reprinted with permission from the American Association for the Advancement of Science.

Figure 5

Bat lyssavirus findings. A, Intracytoplasmic inclusions in a Purkinje cell from the cerebellum of a 39-year-old woman who died of bat lyssavirus encephalitis following a bat scratch. B, A Daubenton bat (Myotis daubentonii), a species commonly implicated in human transmission of bat lyssavirus. C and D, Electron micrographs at × 37 500 (C) and × 104 000 (D) showing lyssavirus particles in a neuronal intracytoplasmic inclusion in longitudinal (C) and cross-section (D) from the same case. Copyright 1998 Blackwell Science Ltd.