This research investigates a global marine disease caused by the ciliate Philaster sp. (DaScPc), responsible for widespread die-offs of Diadema sea urchins. By combining laboratory culturing with field and aquaria studies, we aim to uncover how environmental conditions and microbiomes influence the growth and transmission of this pathogen. Our team is identifying environmental reservoirs and testing how microbiome composition affects disease susceptibility. This work provides critical insight into disease ecology in the ocean and informs strategies to protect vulnerable coral reef ecosystems. The project also supports student training and public engagement through outreach and community science efforts.