Screening for strongyloidiasis among selected populations in Taiwan: Prevalence, associated factors, and outcomes

When and how to screen for strongyloidiasis in high-income countries remain to be elucidated. This study aimed to investigate the prevalence, associated factors, and outcome of strongyloidiasis in Taiwan and proposed clinical criteria for serological screening.

Adults who were immunocompromised or about to undergo iatrogenic immunosuppression (proactive-screening cohort) and those with clinical presentations suggesting strongyloidiasis (diagnosis-driven cohort) were prospectively enrolled at five hospitals in Taiwan. Serum anti-Strongyloides IgG was determined by two enzyme-linked immunosorbent assays (ELISAs). Stool samples were obtained for microscopy and cultures. Prevalence of confirmed/probable strongyloidiasis, as defined by identification of characteristic larvae from stool or testing positive for both ELISAs, was calculated. Factors associated with strongyloidiasis were identified in multivariable analysis. Six-month mortality was compared between participants with and without strongyloidiasis using Cox proportional hazards model.

From January 2021 to June 2024, confirmed/probable cases of strongyloidiasis were identified in 1.9 % and 4.8 % of the participants in proactive-screening and diagnosis-driven cohorts, respectively. Multivariable analysis revealed that skin and skin structure infection (adjusted odds ratio [aOR] 3.180), gastrointestinal bleeding of unknown causes (aOR 3.229), and hemoglobin <10 g/dl (aOR 4.300) were independently associated with strongyloidiasis. Six-month mortality was 33.3 % in participants with confirmed/probable strongyloidiasis, higher than that in those without strongyloidiasis (11.4 %), but not statistically significant after adjusting for age, sex, and clinical severity (p = 0.09).

Strongyloidiasis continued to occur among at-risk populations in Taiwan. Screening strategies are needed to improve the detection of this neglected parasitic infection in Taiwan and other high-income countries.