Prevalence, type, and prognosis of ocular lesions in shelter and owned-client dogs naturally infected by Leishmania infantum

Aim: The point prevalence of ocular lesions due to leishmaniasis was evaluated in 127 dogs living in a municipal shelter placed in a highly endemic area (Sicily, Italy). Moreover, the period prevalence, the type, and prognosis of lesions due to leishmaniasis were evaluated in 132 dogs with ocular pathologies referred to a Veterinary Teaching Hospital (VTH) in the same endemic area over a 3-year period. Materials and Methods: All the dogs were submitted to ophthalmological examination. The diagnosis of leishmaniasis was made by cytological, serological (immune-fluorescent antibody test), and molecular (quantitative polymerase chain reaction) tests. Results: The point prevalence of ocular lesions in 45 shelter dogs with leishmaniasis was 71.11% (45/127 dogs). The most frequent ocular lesion was blepharitis (50%) while anterior uveitis was observed in only 9.37% of cases. The period prevalence of ocular lesions due to leishmaniasis in the VTH group was 36.36% (48/132 dogs). In both groups, most of the lesions were bilateral and involved the anterior segment. Anterior uveitis was the most frequent ophthalmic finding in client-owned dogs (37.50%), but it occurred in only 9.37% of the shelter dogs. Keratouveitis often occurred during or after antiprotozoal treatment (14.58%; 7/48). In this study, the healing of eye injury following systemic antiprotozoal treatment was recorded in about half of cases (48%; 12/25 dogs), in which follow-up was possible. In more than 1/3 of cases (36%; 9/25), there was an improvement, but it was necessary to associate a long-term topical treatment; most of them, as well as those who had not responded to systemic therapy (16%; 4/25), had anterior uveitis or keratoconjunctivitis sicca. Conclusions: Ocular manifestations involve up to 2/3 of animals affected by canine leishmaniasis and lesions account for over 1/3 of ophthalmic pathologies observed at a referral clinic in an endemic area. The occurrence of anterior uveitis is more frequent in client-owned dogs than in shelter dogs. The onset of keratouveitis during or after antiprotozoal treatment could be attributed to the treatment or to a recurrence of the systemic form. The post-treatment uveal immune reaction, already observed in humans, could explain the difference in the frequency of keratouveitis between client-owned and shelter dogs, which have never been treated.