Determinants of reactivation of inapparent Strongyloides stercoralis infection in patients hospitalized for unrelated admitting diagnosis

BACKGROUND: Clinical presentation of strongyloidiasis in humans is highly variable, ranging from clinically inapparent infection to life-threatening multisystem disease. The course of infection is dependent on the immune status of the patient. Our objective was to ascertain the clinical characteristics of patients who developed reactivated strongyloidiasis from a primary infection acquired in the past, and to evaluate risk factors that contributed to its exacerbation. METHODS: We identified 31 patients diagnosed with strongyloidiasis by stool examination at our institution from January 2007 to June 2012. We reviewed their clinical records and selected eight patients whose admitting diagnosis was not suggestive of strongyloidiasis-associated gastrointestinal disease. However, they developed symptoms consistent with strongyloidiasis during their hospitalization, and stool examinations revealed diagnostic larvae. RESULTS AND CONCLUSION: We have identified immunosuppressive therapy, viral infection-associated immunodeficiency, alcoholism, and diabetes mellitus as risk factors for reactivation of chronic inapparent strongyloidiasis. Analysis of hemogram data suggests the low sensitivity of hypereosinophilia to be a marker for this helminthiasis.