PROJECT SUMMARY/ABSTRACT Seasonal and epidemic conjunctivitis (pink eye) infections are highly contagious and impose significant economic burden in the United States and worldwide. Long-term visual impairment can occur. In children, conjunctivitis may herald more serious systemic complications leading to hospitalizations and even deaths. Current challenges to effective mechanisms to curtail outbreaks are the lack of tracking and reporting, poor access to sample collection for analysis, limited diagnostic testing capabilities, and an incomplete understanding of the pathogens involved. The overall goal of this project is to combine international collaboration efforts and advances in genomic technologies to identify pathogens, global trends, pathogen evolution, and the immune responses involved in the epidemiology of conjunctivitis. We propose to enhance the understanding of the pathogenesis of conjunctivitis with the following aims. The first aim will determine how adenovirus genome types vary within a region and across regions. The second aim will identify emerging causes of seasonal and epidemic conjunctivitis. Finally, we will identify the local immune response signatures of children and adults with infectious conjunctivitis. We expect that conjunctival gene expression profiles will accurately predict disease associated complications. This project has the potential to improve public health surveillance, guide targeted interventions, improve vaccine development, and elevate existing diagnostic paradigms for conjunctivitis, to reduce both the financial and ocular health burden worldwide.