Emerging Disease of the Desert: Rise of West Nile Virus Chorioretinitis in Arizona

Abstract

Purpose: To present 7 cases of West Nile virus (WNV)-related chorioretinitis in Arizona. Methods: Retina clinic charts with the terms "chorioretinitis" and "West Nile" were selected from April 1, 2012, to February 1, 2023. Results: Seven patients with initial visits between August 2019 and February 2023 were included. The majority of WNV chorioretinitis cases were seen in the last 4 years of the selected dates. Only 1 patient presented before this time but was excluded for inadequate baseline testing. All 7 patients had hospitalization for neuroinvasive disease before clinical presentation. All patients achieved a final visual acuity of 20/25 to 20/70. Conclusions: In the last 4 years of the study period, an uptrend in WNV chorioretinitis was found in our retina clinics in Arizona, reflecting the overall rise in WNV outbreaks across the state. As WNV continues to rise, the eye specialist should have high suspicion for WNV ocular disease, even in states where WNV had been an uncommon entity.

Keywords: West Nile virus; chorioretinitis; climate; inflammatory and infectious diseases; uveitis.

Figure 1.

Case 3, initial visit. (A and B) Fundus photographs of the right eye and left eye, respectively, show a hazy view to the posterior pole along the inferior arcade resulting from vitritis and no obvious chorioretinal lesions. (C and D) Autofluorescence of the right eye and left eye, respectively, shows small chorioretinal lesions arranged in a curvilinear streak off superior and inferior parafoveal vessels. (E and F) Early fluorescein angiography (FA) of the right eye and left eye, respectively, at 1 minute shows more numerous small rings of hyperfluorescence along the superior and inferior parafoveal vessels than can be seen on other imaging, with more pronounced curvilinear streaks of small hyperfluorescent lesions in the left eye than in the right eye. (G and H) FA of late phase at 3 minutes for the right eye (G) and at 4 minutes for the left eye (H) shows late staining of the lesions with disc leakage.

Figure 2.

Case 3, imaging 1 month after clinic presentation. (A–D) Nearly resolved vitreous haze in both eyes with persistent subtle chorioretinal scarring in both eyes. (E–H). Fluorescein angiography (FA) at 1 minute in the right eye (E) and left eye (F) shows persistent but lighter hyperfluorescence of the curvilinear chorioretinal scarring in the superior more than inferior parafoveal areas in both eyes. FA at 3 minutes 30 seconds in the right eye (G) and left eye (H) eyes shows late staining to a lesser degree than at the initial visit.

Figure 3.

Case 2. (A) Fundus photograph of the right eye shows multiple yellow–white chorioretinal lesions, some of which have coalesced into a vertical linear streak involving the foveal center macula. Others are found scattered in the macula and extending into the midperiphery in a perivascular pattern. Paracentral exudate and a couple of small intraretinal hemorrhages in the superior macula are seen. (B) Fundus photograph of the left eye shows a temporal macular intraretinal hemorrhage, a couple of yellow–white chorioretinal lesions nasal to the disc, and isolated lesions off the inferior arcade below the temporal macula. (C–F) Autofluorescence and red-free images emphasize the chorioretinal lesions, which show hyperautofluorescence surrounded by a ring of hypoautofluorscence in the right eye (shown in C). (G and H) Fluorescein angiography (FA) in the midphase at 30 seconds in the right eye and in the later phase at 1 minute in the left eye shows multiple nummular lesions with central hypofluorescence and a ring of hyperfluorescence. (I and J) FA of the right eye at 2 minutes (late phase) and an eccentric nasal photograph in the left eye at 6 minutes shows staining of the lesions. (K and L) An optical coherence tomography horizontal line scan through the foveal center of the right eye shows a thin retina, disorganized outer retinal layers, ellipsoid zone layer and retinal pigment epithelium disruption, and a focal area of inner retinal layer hyperreflectance correlating with the chorioretinal lesions on examination. The horizontal line scan through the central macula of the left eye shows no chorioretinal involvement but does show mild temporal intraretinal cystic fluid related to diabetes.