2020–2021 BCSC Basic and Clinical Science Course™
12 Retina and Vitreous
Part II: Disorders of the Retina and Vitreous
Chapter 11: Focal and Diffuse Choroidal and Retinal Inflammation
Infectious Retinal and Choroidal Inflammation
West Nile Virus Chorioretinitis
West Nile virus (WNV) infection is transmitted to humans by an infected mosquito of the genus Culex, with birds serving as the primary reservoir. Human infection is most often subclinical, although a febrile illness occurs in approximately 20% of cases. Ocular manifestations usually occur in very ill diabetic patients with encephalitis. The manifestation most typically observed is a multifocal chorioretinitis that is usually bilateral and includes lesions arranged in distinctive curvilinear clusters that often follow the course of retinal nerve fibers (Fig 11-24). Vision typically remains good unless the lesions involve the central macula.
Figure 11-24 Fundus photograph montage of West Nile virus chorioretinitis. Fluorescein angiography images show punched-out lesions that characteristically arrange in almost confluent streaks in some areas. Alterations caused by nonproliferative diabetic retinopathy are also apparent; West Nile virus chorioretinitis typically occurs in diabetic patients.
(Courtesy of Robert Beardsley, MD, and Colin A. McCannel, MD.)
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.