A Case Report of Presumed West Nile Virus Chorioretinitis in a Non-Endemic Area: Atypical Serology and Imaging Features of Old and New Lesions.

INTRODUCTION

West Nile virus (WNV) infection is a recognized cause of neuroinvasive disease and chorioretinitis, typically reported in endemic regions and often associated with positive IgM serology. However, atypical presentations with discordant serology can occur, particularly in non-endemic settings, posing diagnostic challenges.

CASE PRESENTATION: A 58-year-old woman developed acute encephalitis and bilateral panuveitis shortly after travel to a non-endemic region. Serum and cerebrospinal fluid testing showed positive WNV IgG and negative IgM. Multimodal retinal imaging revealed the coexistence of inactive-appearing chorioretinal scars and active full-thickness retinitis, with characteristic wedge-shaped and linear lesion patterns. Fundus autofluorescence, fluorescein angiography, indocyanine green angiography, and optical coherence tomography allowed differentiation of lesions with varying morphology and stages of activity. Although these findings do not confirm viral relapse or reactivation, they suggest prior infection with possible delayed or recurrent ocular and central nervous system involvement. Systemic and topical corticosteroid therapy resulted in rapid clinical and imaging improvement.

CONCLUSION

This case highlights the diagnostic value of multimodal imaging in suspected WNV chorioretinitis and underscores the limitations of serology alone. Atypical serological profiles in non-endemic settings require careful interpretation, and multimodal imaging may provide critical insights into disease activity and staging.