PROJECT SUMMARY Neurocysticercosis (NCC) is a common neurologic disease and a leading cause of preventable epilepsy across the developing world. It is caused by central nervous infection with Taenia solium (the pork tapeworm) larval cysts. While most cases of NCC have a relatively benign clinical course, the prognosis is grim for infections involving the subarachnoid space (SANCC). New approaches are needed to improve outcomes for patients with this devastating malignant form of infection. One promising approach involves early detection through population screening, which would allow early intervention while the burden of infection is low and while the patient retains relatively good health. We recently developed an assay that detects T. solium antigens excreted in the urine, and have now shown in pilot studies that this assay can be used to detect asymptomatic people with SANCC in the community setting. In this 5-year project we will validate the new assay by applying it in a large cross-sectional study in northern Peru (30,000), using magnetic resonance imaging (MRI) of the brain as the gold standard to confirm diagnosis. Participants subsequently diagnosed with asymptomatic SANCC will be enrolled in either an 18-month prospective observational cohort to determine risk of disease progression, or a small clinical trial evaluating safety of early intervention for asymptomatic SANCC. Furthermore, we will develop a prototype point-of-care format of the assay and validate it with samples gathered from the community. The results of these studies will provide information and tools necessary to conduct a definitive randomized clinical trial evaluating the efficacy of screening and early intervention as an approach to improve clinical outcomes of patients with SANCC. We will also provide a series of didactic and hands-on laboratory and clinical research training opportunities for students from northern regions of Peru.