Clinical manifestations and outcomes of West Nile virus infection

Abstract

Since the emergence of West Nile virus (WNV) in North America in 1999, understanding of the clinical features, spectrum of illness and eventual functional outcomes of human illness has increased tremendously. Most human infections with WNV remain clinically silent. Among those persons developing symptomatic illness, most develop a self-limited febrile illness. More severe illness with WNV (West Nile neuroinvasive disease, WNND) is manifested as meningitis, encephalitis or an acute anterior (polio) myelitis. These manifestations are generally more prevalent in older persons or those with immunosuppression. In the future, a more thorough understanding of the long-term physical, cognitive and functional outcomes of persons recovering from WNV illness will be important in understanding the overall illness burden.

Figure 1

Diffuse maculopapular rash associated with West Nile virus infection.

Figure 2

Fluid-attenuated inversion recovery magnetic resonance imaging sequence of the brain in a patient with West Nile virus encephalitis with associated parkinsonism and tremor, displaying signal abnormality in the substantia nigra (short arrow), the mesial temporal lobe (long arrow) and right posterior thalamus (thick arrow).

Figure 3

Sagittal (A) and axial (B) T2-weighted magnetic resonance imaging of the cervical spinal cord of a patient with bilateral upper extremity paralysis and respiratory failure from West Nile poliomyelitis, displaying the increased signal in the anterior spinal cord (circle and arrow).