Chronic Strongyloides stercoralis infection in former British Far East prisoners of war

Abstract

Chronic infections with the nematode worm Strongyloides stercoralis can occur in former WWII Far East prisoners of war (FEPOWs). The condition may be asymptomatic, but frequently causes a characteristic urticarial 'larva currens' rash. Under conditions of immunosuppression (particularly systemic corticosteroid treatment) potentially fatal dissemination of larvae ('hyperinfection') may occur. To review our total experience of strongyloidiasis in former FEPOWs, and investigate its prevalence, characteristics and risk factors. Retrospective case series. We reviewed 2072 records of all FEPOWs seen at the Liverpool School of Tropical Medicine, 1968-2002. Cases with strongyloidiasis were compared with non-infected controls. There were 248 (12%) with strongyloidiasis. Diagnostic features included larva currens rash (70%), eosinophilia (66%), positive faecal culture (30%), positive faecal microscopy (26%), and positive serology (64%). Mean (+/-SD) age of cases was 65 +/- 7 years, and as expected, their blood eosinophil counts were significantly higher than controls (775 vs. 238 x 10(6)/l, p < 0.001). Captivity on the Thai-Burma Railway (vs. elsewhere) was significantly associated with strongyloidiasis (78% cases vs. 40% controls, OR 4.19, CI 2.70-6.81, p < 0.001). In terms of prevalence, strongyloidiasis occurred in 166/1032 men imprisoned on the Burma Railway (16.1%). Malaria (88% vs. 69%, p < 0.001) and tropical ulcer (53% vs. 42%, p < 0.02) were more common amongst cases than controls, probably because these diseases were very common on the Burma Railway. S. stercoralis infection is common amongst ex-FEPOWs, particularly those from the Thai-Burma Railway project. It is usually characterized by a 'larva currens' rash and marked eosinophilia. The condition is eminently treatable, and continued diagnostic surveillance is needed, if cases of potentially fatal hyperinfection are to be avoided.