Seroprevalence of <i>Strongyloides stercoralis</i> Among Pediatric Solid Organ Transplant Candidates at a Tertiary Pediatric Medical Center in the United States

BACKGROUND: SOT recipients with prior Strongyloides stercoralis infection risk hyperinfection post-transplant. Risk-based screening may miss at-risk candidates as endemicity expands beyond classic regions. METHODS: Retrospective study of SOT candidates < 26 years at Cincinnati Children's Hospital (2018-2024). Universal serology-based screening was implemented in 2023. Seroprevalence was estimated with exact 95% CIs; seropositive and seronegative patients were compared on demographic and exposure characteristics. RESULTS: 178 patients were screened. Seroprevalence was 3.4% (6/178; 95% CI 1.2%-7.2%), similar across pre-universal (4.3%) and universal (2.9%) screening periods. Seropositive patients were older (15.7 vs. 8.5 years; p = 0.015) but did not differ on Appalachian exposure, international travel, eosinophilia, or other classical risk factors. Half of seropositive patients lacked any identifiable exposure criterion. All were asymptomatic and treated with two-dose ivermectin. CONCLUSIONS: S. stercoralis seroprevalence was low but clinically significant in this non-endemic pediatric SOT cohort. Risk-based screening would have missed a meaningful proportion of seropositive candidates, supporting consideration of universal screening and underscoring the need for broader regional seroprevalence data.