Animal models of herpetic retinitis

The Herpes simplex virus (HSV) is characterized its ability to replicate in the nervous system, before inducing a latent infection with potential reactivation. Most frequent ocular complications of recurrent HSV infection are keratitis and conjunctivitis. Less frequently, the iris and the ciliary body may also be involved (anterior uveitis). The most severe HSV ocular infection is retinitis, a rare but potentially blinding disease, due to frequent bilateral involvement. Studies on human post‐mortem tissues showed that HSV is widely distributed in the population, with a preferential location within the trigeminal ganglions (innervating the cornea), but also in the superior cervical ganglions (innervating the iris) or in brain/medullar tissues (innervating the retina). Animal models have been developed to understand the pathogenic processes that lead to this rare but devastating retinal disease. Since human is the only natural host of HSV, it is difficult to obtain a perfect animal model that perfectly mimics the disease. Several animal models, based on different inoculation procedures, are thus necessary to circumscribe the anatomical, cellular and molecular aspects that lead to retinal infection. Finally, HSV retinitis appears as a clinical condition that is highly constrained by the relationships between the strain of the virus and the immune response of the host.