Clinical and pathologic evaluation of chorioretinal lesions in wild owl species

Abstract

Objective Investigate histopathology and spectral‐domain optical coherence tomography (OCT) imaging of wild owls with chorioretinitis and identify any potential correlation with an infectious etiology. Materials and Methods Ophthalmic examination and retinal OCT imaging were performed on fifteen great horned (Strix varia) and barred (Bubo virginianus) owls (30 eyes) with chorioretinitis and five owls with normal eyes (10 eyes). Testing to investigate the presence of potential infectious diseases included a complete blood count, biochemistry, protein electrophoresis, West Nile virus (WNV) plaque reduction neutralization test, Toxoplasma gondii modified direct agglutination test, WNV RT‐PCR, and Avian Influenza RT‐PCR. A necropsy was performed on all owls, including ocular histopathology. Results Fundus lesions included retinal detachment (7/15 owls), depigmented lesions (12/15), pigment clumping (8/15), and retinal tear (4/15). All birds were negative for WNV and Avian Influenza on RT‐PCR. Of the owls with chorioretinitis, 3/15 were seropositive for WNV and 7/15 for T. gondii. Optical coherence tomography of 25/30 affected eyes revealed outer retinal lesions (19/25 eyes), retinal detachment (16/25), and retinal tears (3/25). Histopathological examination revealed outer nuclear layer atrophy (19/30 eyes), retinal detachment (18/30), retinal tears (7/30), suprachoroidal hemorrhage (12/30), scleral rupture (3/30), and ossicle fracture (3/30). Conclusions Although 20% of birds were seropositive for WNV and 46.6% for T. gondii, histopathologic findings supported that the posterior segment lesions in the study group were likely due to blunt ocular trauma rather than an infectious etiology. The results of OCT imaging and histopathology documented retinal changes most consistent with blunt ocular trauma.

In Vivo Imaging of Retinal and Choroidal Morphology and Vascular Plexuses of Vertebrates Using Swept-Source Optical Coherence Tomography

“…A lesion found in the subRPE space seen in Figure 9 H (pink hollow arrow) is reminiscent of a druse observed in human retinas. A representative histology cross-section of a great horned owl retina is shown in Figure 9 G. 39 The retinal layers in the histology cross-section are closely correlated with the OCT B-scan images. OCTA images confirm that an avascular retina is overlying a highly vascularized choroid, shown as an en face image in Figure 9 I.…”

“…( G ) Representative histological section of a great horned owl retina. 39 ( H ) B-scan corresponding to the location represented by the orange dashed arrow in ( E ). OCTA en face image: ( I ) Depth-projected (average) OCTA image of the choroid.…”

Use of a Smartphone-Based Device for Fundus Examination in Birds: A Pilot Study

“…Ocular lesions are described in different species admitted to wildlife rehabilitation centers and consist of retinal detachments or tears (71% according to Moore et al, 2017) [ 31 ]. They also include retinal discoloration, posterior uveitis, pecten lesions, and chorioretinitis [ 4 , 5 , 32 ]. The smartphone device detected retinal lesions in three birds that were affected in our group.…”

Comparison of West Nile Virus Disease in Humans and Horses: Exploiting Similarities for Enhancing Syndromic Surveillance

“…Manifestations include chorioretinitis, anterior uveitis, vitritis, and retinal hemorrhage [ 153 , 154 ]. Ophthalmic changes have not been documented in the horse but have been documented in birds of prey and waterfowl [ 158 , 159 , 160 , 161 ]. Gastrointestinal signs such as nausea, abdominal pain, and diarrhea have been documented in humans [ 155 , 156 , 157 ].…”