Molecular diagnosis and ocular imaging of West Nile virus retinitis and neuroretinitis

Abstract

Purpose: To describe the ocular features of West Nile virus (WNV) infection proven by serology and molecular diagnostic techniques.

Design: Prospective case series.

Participants: Fifty-two patients who presented to the uveitis clinic with ocular inflammatory signs and history of fever preceding ocular symptoms between January 2010 and January 2012 were enrolled for laboratory diagnosis. Serum samples were collected from 30 healthy controls from the same geographic area.

Methods: Patients were tested for all endemic infectious diseases that can cause ocular inflammation by serology or molecular diagnostics. When patients had positive antibodies for WNV, serum/plasma samples were tested by real-time reverse transcription (RT) polymerase chain reaction (PCR) and RT loop-mediated isothermal gene amplification assays. The PCR product was subjected to nucleotide sequencing. Fundus fluorescence angiography (FFA), optical coherence tomography (OCT), and indocyanine green angiography were performed. Visual prognosis was analyzed.

Main outcome measures: Clinical signs (retinitis, neuroretinitis, and choroiditis) and ocular complications (decrease in vision).

Results: A total of 37 of 52 patients (71%) showed positive results for at least 2 laboratory tests for WNV. Fundus examination revealed discrete, superficial, white retinitis; arteritis; phlebitis; and retinal hemorrhages with or without macular star. The FFA revealed areas of retinal inflammation with indistinct borders, vascular and optic disc leakage, vessel wall staining, or capillary nonperfusion. Indocyanine green angiography confirmed choroidal inflammation in 1 of the patients who was diabetic. The OCT scan of the macula revealed inner retinal layer edema in active inflammation and retinal atrophy in late stage. At the final visit, 43% of patients had visual acuity better than 6/12.

Conclusions: In addition to previously reported clinical signs, retinitis, neuroretinitis, and retinal vasculitis were seen in this population. Atrophy of the inner retinal layer was seen on OCT after resolution of inflammation. Visual prognosis was good in patients with focal retinitis and poor in patients with occlusive vasculitis.

Financial disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article.