The ocular surface, a target for One Health indicators: the mirror of microbial interactions between pets and owners and an indicator of air pollution

One Health aims at tackling health issues with a comprehensive approach, encompassing human, animal and environmental health. Relationships between human health and the health of wildlife or livestock animals have been explored, however very few studies focus on the relationship between owner and companion animal. Evidence of pathogen sharing, including antimicrobial-resistant pathogens, between companion animal and owner highlights the existence and the importance of both pathogenic and non-pathogenic microbial exchanges and calls for a One Health approach to study the microbiomes. Outdoor air pollutants are known to have a negative impact on the ocular surface, however, their impact on the ocular surface microbiome, hosted by the conjunctiva, is not yet known. The conjunctiva has the particularity of being the only mucosa of the body directly exposed to the external environment. For this reason, it could act as a sentinel of the body identifying these interactions. The goal of this research was to apply a One Health approach to the study of the ocular surface microbiome, by combining several disciplines to investigate microbiome similarities between pet and owner, and the impact of pollutant exposure on the ocular surface. The research entails the implementation of a pipeline for the sampling, processing, and sequencing of the ocular surface microbiome in dogs and owners. 15 dogs and their owners were included in the study. Dog and owner microbiomes were found to be similar in overall composition, harboring the same main phyla and families, albeit dogs having a significantly more diverse microbiome. Pairs cohabiting with other pets had an ocular surface microbiome composition significantly more similar than the ones who did not. This is the first research evaluating ocular surface microbiome interactions between pet and owner. The ocular surface is proposed as a valuable indicator of pathogenic and non-pathogenic microbial exchanges, and pollution exposure.