Strongyloides stercoralis in the US Military Health System

BACKGROUND: Strongyloides stercoralis is an intestinal nematode most commonly found in subtropical and tropical locations. Military service members are believed to be at increased risk of exposure due to their unique occupational exposures in endemic regions. METHODS: Burden, clinical course, and risk factors associated with all Strongyloides infections within the US Military Health System from fiscal years 2012 to 2019 were assessed by manual chart review of records with International Classification of Diseases, Ninth Revision/Tenth Revision codes for Strongyloides infection. Infection risk in demographic subgroups based on region of birth, military occupation, and age was quantified with univariate analysis and multivariate logistic regression. RESULTS: We reviewed 243 charts based on diagnosis coding, yielding 210 confirmed diagnoses (86.4%). Immigrant patients born in Latin America/Caribbean, sub-Saharan Africa, and East Asia/Pacific regions had statistically significant increased risk ratios of infection at 34.4, 32.0, and 22.4, respectively, when compared to patients born in Europe and North America. In univariate analysis, active duty members in the healthcare occupational category had a statistically significant increased risk ratio of infection at 2.31 compared to those outside this occupation. Multivariate logistic regression analysis demonstrated that occupational categories of healthcare, admininstrative/support, warfighter/combat specialist, and engineering/repair/maintenance occupations, being an immigrant patient, and age ≥65 were all associated with statistically significant increased odds ratios for infection. CONCLUSIONS: In the Military Health System, occupational exposures, region of birth, and age serve as risk factors for Strongyloides infection. Because infections may be chronic, the impact of targeted screening programs to complement routine medical care should be considered.