Epidemiological and Molecular Investigation of Ocular Fungal Infection in Equine from Egypt

Abstract

Diagnosis and treatment of ocular fungal infection in equine seems very challenging for owners and clinicians. The present study aimed to identify and characterize fungal species isolated from the eyes of clinically healthy and diseased equines (N = 100) from Dakahlia Governorate, Egypt. The work also involved morphological and molecular characterization of the major fungal species. In addition, correlations between the occurrence of isolated fungi and some of the potential risk factors were also investigated. Interestingly, the prevalence rate of ocular mycosis in all examined equines in the study was 28% and there were major clinical signs associated with ocular fungal infection. Moreover, the identified fungal species included <i>Aspergillus flavus</i>, <i>A. fumigatus</i>, <i>A. niger</i>, <i>Penicillium</i> spp., <i>Mucor</i> spp., and <i>Alternari</i> spp. with a corresponding prevalence rate of 63.9%, 27.8%, 15.3%, 18.1%, 13.9%, and 4.2%, respectively, in healthy equine eyes, while their prevalence in diseased equine eyes was 57.1%, 32.1%, 21.4%, 7.1%, 3.6%, and 0%. Furthermore, a statistical significant association (<i>p</i> < 0.05) was found between the frequency of isolation of <i>A. fumigatus</i> and <i>Penicillium</i> and several risk factors (breed, sex, and ground type), while the remaining risk factors and occurrence of fungi were not statistically correlated. A subset of the <i>Aspergillus</i> species samples positive by polymerase chain reaction (PCR) were sequenced and their phylogenetic analysis identified three species of <i>Aspergillus</i>. Taken together, our study provides novel data related to the occurrence of ocular mycosis in equine in Egypt. Given the zoonotic potential of some identified fungi, our data may be helpful for implementation of novel diagnostic and therapeutic strategies for combating this sight-threatening infection in equine.