Ebola virus tropism in ex vivo cynomolgus macaque ocular tissues.

Ocular complications of Ebola virus disease have been documented extensively, particularly following the 2013-2016 epidemic in west Africa. The eye is known to serve as a site for persistent Ebola virus infection in some individuals, even after clearance of viremia. Additionally, long-term ocular sequelae in survivors are common and lead to considerable morbidity. However, little is currently known regarding the tropism and replication kinetics of Ebola virus in different ocular tissues. To date, a limited number of studies have made use of in vitro infections of ocular cell lines and retrospective analyses of archived pathology data from previous animal challenge experiments to further investigate the behavior of Ebola virus in the eye. In this study, we utilized ex vivo cultures of cynomolgus macaque eyes to determine the tropism of Ebola virus in seven different ocular tissues: cornea, anterior sclera with bulbar conjunctiva, ciliary body, iris, lens, neural retina, and retina pigment epithelium. We report that, except for neural retina, all these tissues supported Ebola virus growth. Retina pigment epithelium consistently produced the fastest growth and the highest viral RNA loads, although the differences with other tissues were not statistically significant. Immunohistochemical staining confirmed Ebola virus infection of the tissues and further characterized tissue tropism. This study demonstrates that Ebola virus has a broad tropism within the eye and suggests that no single tissue serves as the primary reservoir for ocular replication.