Author Block: Marie-Josée Aubin, Cristina Bostan, Mariam T. Ibrahim, Mark Bamberger, Karin M. Oliver
Author Disclosure Block: M. Aubin: Any direct financial payments including receipt of honoraria; Name of for-profit or not-for-profit organization(s); University of Ottawa Eye Institute, Gilead. Description of relationship(s); Honoraria. Funded grants or clinical trials; Name of for-profit or not-for-profit organization(s); Gilead, PeriPharm. Description of relationship(s); Research grant. C. Bostan: None. M.T. Ibrahim: None. M. Bamberger: None. K.M. Oliver: Any direct financial payments including receipt of honoraria; Name of for-profit or not-for-profit organization(s); AbbVie. Description of relationship(s); Honoraria. Membership on advisory boards or speakers’ bureaus; Name of for-profit or not-for-profit organization(s); AbbVie. Description of relationship(s); Consultant.

Abstract Body:

Purpose: To describe the ocular clinical features and imaging findings associated with West Nile virus (WNV) infection and raise awareness as to their diagnostic importance in the context of the current resurgence of human WNV cases in Canada.
Study Design: Case series.
Methods: Medical chart review of three patients (one male, two females; 41 to 62 years old) seen in two tertiary eye care centers in Montreal, Canada, who had confirmed WNV infection. Their ophthalmologic evaluation included Snellen visual acuity (VA), complete slit-lamp dilated eye exam, spectral domain optical coherence tomography (SD-OCT), and fundus fluorescence angiography (FFA).
Results: The first patient experienced mild fever and generalized malaise, for which she did not seek medical care. She presented due to unilateral decreased visual acuity and floaters and her ophthalmic evaluation led to the WNV diagnosis. The other two patients had been admitted to the intensive care unit with an altered level of consciousness and fever, and were diagnosed with meningoencephalitis. An ophthalmology consultation for these patients was sought after serologic identification of WNV infection, which only became available two weeks after admission. All patients presented typical unilateral (1) or bilateral (2) multifocal placoid yellow-white chorioretinal lesions with variable pigmentation, and linear clustering following the course of the nerve fiber layer, consistent with WNV chorioretinitis. FFA revealed centrally hypofluorescent round lesions with peripheral hyperfluorescence and late staining. On SD-OCT the lesions appeared as hyper-reflective foci located at the outer retinal and sub-retinal pigment epithelial levels.
Conclusions: The public health implications of WNV infection lend special importance to early diagnosis. Clinical suspicion can be challenging since systemic manifestations are not specific. Confirmatory identification of the virus relies on serologic testing, which is associated with a significant delay. WNV chorioretinitis is characterized by placoid multifocal linearly distributed chorioretinal lesions. It develops in the acute phase in up to 80% of hospitalized WNV patients and has been found to have 100% specificity for WNV infection. Despite supporting evidence in the literature, the diagnostic value of these chorioretinal lesions is little known by medical practitioners. With increased awareness of this pathognomonic ophthalmic involvement in WNV, patients will potentially benefit from early ophthalmologic assessment, earlier access to appropriate services for their systemic disease, and appropriate ocular treatment to reduce potentially vision-impairing complications.