Ocular zoonoses

Abstract

Ocular zoonoses are relatively uncommon causes of ocular inflammation. Among the 175 well-described zoonotic diseases, approximately 30 are known to cause human ocular infections. In this article, we review the most prevalent ocular zoonoses indigenous to North America or Europe. The infections cause toxoplasmosis, toxocariasis, Lyme disease, cat-scratch disease and leptospirosis. Diagnoses of toxoplasma posterior uveitis and ocular toxocariasis are principally based on ophthalmologic findings. Laboratory tests, including antibody titers in ocular fluids, help to support diagnosis when ocular manifestations are atypical. A new trend in toxoplasmosis treatment is to replace sulfadiazine with azithromycin. Trimethoprim/sulfamethoxazole (cotrimoxazole) has proven efficacy in reducing recurrences of toxoplasmic retinochoroiditis. Ocular manifestations of Lyme disease are protean, but the most common are intermediate uveitis and retinal vasculitis. Parinaud oculoglandular syndrome and neuroretinitis with macular stellate exudates are highly suggestive of Bartonella henselae infection (bartonellosis). Diagnoses of the ocular manifestations of leptospirosis and Lyme disease are mainly based on positive histories of animal exposure, nonophthalmologic findings and laboratory investigations. Nongranulomatous uveitis, hypopion, vitritis, membranous veil-like opacities, disk edema and retinal periphlebitis are characteristic features of leptospirosis uveitis. Recent studies showed that PCR tests for bacteria in ocular specimens help in diagnosis (e.g., of infectious uveitis).