Strongyloides Screening in Heart Transplant Candidates

Abstract

The ability of Strongyloides to establish auto-infection in the human host allows it to sustain subclinical infection that can go on for a lifetime. In solid-organ transplant recipients, Strongyloides can cause hyper-infection syndrome which has very high morbidity and mortality. Clinical suspicion for chronic infection should be considered for any persons with birth or travel to endemic regions, history of incarceration, homelessness and group home residence. Targeted screening based on epidemiologic risk is recommended by AST and ISHLT however, testing remains challenging due to variability in the diagnostic yield of currently available serologic assays. We performed a retrospective chart review of heart transplant (HT) recipients from 2010-2019, who had Strongyloides serologic screening performed pre-transplant, with the aim to correlate results with epidemiological risk factors for infection. Two-hundred and fifty HT recipients were reviewed. Of these, 197 had pre-transplant Strongyloides serology performed, in accordance with institutional policy of universal pre-transplant screening. Based on serologic testing, prevalence of strongyloidiasis was 2.5%. Of the 5 patients with positive serology, all but 1 had epidemiologic risk for infection; 3 due to birth in an endemic region and 1 due to history of incarceration. Eosinophilia was noted in 3/5, all of whom were from endemic regions by birth. All with positive serologic screening were treated pre-transplant with ivermectin. One-hundred and ninety two patients tested negative for Strongyloides, and 58% (111/192) of those had epidemiological risk factors, due to birth (90) or travel to endemic regions (21). There were no cases of clinical strongyloidiasis in the study cohort. In this population with high epidemiologic risk, we found a lower than expected rate of Strongyloides infection. Given the variability in diagnostic yield across commercially available serologic assays, these findings raise the possibility of false negative results and thus, bring into question the utility and reliability of using serologic testing alone, for screening of Strongyloides infection among HT candidates. Accordingly, a thoughtful assessment of epidemiologic risk is essential for appropriate risk stratification and management of Strongyloides in HT candidates and recipients.