Ocular Disease Associated with West Nile Virus Infection

Chorioretinal involvement, frequently asymptomatic and self-limited, is common in patients with West Nile virus (WNV) infection associated with neurologic illness. A bilateral multifocal chorioretinitis, with typical clinical and fluorescein angiographic features, is the most common finding, but numerous other ocular manifestations can occur. Diabetes mellitus appears to be a potential risk factor for developing severe neurologic disease and also severe chorioretinitis. The unique pattern of multifocal chorioretinitis can help establish an early diagnosis of the disease while serologic testing is pending. This might be of utmost importance in the near future for early initiation of promising drugs currently under investigation. Therefore, an ocular examination, including dilated fundus examination and fluorescein angiography in selected cases, should be part of the routine evaluation of patients with clinically suspected WNV infection. WNV infection should be considered in the differential diagnosis of multifocal chorioretinitis in patients living in or returning from specific endemic regions.