Strongyloides stercoralis: risks posed to immigrant patients in an Australian tertiary referral centre

Strongyloides stercoralis is a nematode human parasite with a global prevalence that is able to maintain a prolonged infestation by means of its autoinfective life cycle. Immunosuppression may result in a life-threatening hyperinfection syndrome. Recent changes in migration have resulted in the arrival of many immigrants from endemic areas. As to whether physicians are alert to the risks of strongyloidiasis in these patient groups is unclear. The aim of the study was to assess the risks posed by chronic strongyloidiasis in patients presenting to a tertiary referral centre and the need for screening of immigrant patients before immunosuppression.

The study comprised a retrospective review of cases of strongyloidiasis presenting to the Alfred Hospital, Melbourne. Thirty-three cases were diagnosed by either positive serology or faecal microscopy between January 1998 and January 2005. The medical records for 29 cases were examined with regard to demographics, clinical features and complications.

Two major groups were identified: immigrants (17) and returned travellers (11). Six immigrants, but no returned traveller, developed a hyperinfective syndrome. Five immigrants received immunosuppressive therapies before developing symptoms of hyperinfection and this was complicated by life-threatening sepsis in two patients. Diagnosis was frequently delayed in the immigrant group who were significantly more likely to present with respiratory symptoms. Four immigrants and two returned travellers were treated with corticosteroids for symptoms that were probably related to larval migration.

Before giving immunosuppressive therapies, patients with a history of potential exposure must be investigated for strongyloidiasis and consideration given to empirical treatment.