Seroepidemiology of Strongyloides stercoralis in Dhaka, Bangladesh.

Human strongyloidiasis is a neglected tropical disease with global distribution and this infection is caused by the parasitic nematode Strongyloides stercoralis. The aim of this study was to determine the prevalence of strongyloidiasis in Dhaka, Bangladesh. Sera from 1004 residents from a slum (group A) and 299 from city dwellers (group B) were tested for total IgG and IgG subclasses to Strongyloides antigen. There was a significant difference (P < 0·001) in IgG seroprevalence between group A (22%) and group B (5%). Reactive IgG subclasses (IgG1 and IgG4) were also higher in group A (P < 0·05). The seroprevalence of strongyloidiasis in group A increased with age but was unrelated to sex. The presence of reactive IgG to Strongyloides antigen had no correlation with either socio-economic or personal hygiene factors. However, a history of diarrhoea in a family member, in the past 6 months, but not in the respondents was associated with detection of antibodies to S. stercoralis (P < 0·01). None of the sera from either group had an HTLV-I reaction. This study demonstrates that strongyloidiasis is prevalent in Dhaka, especially among slum dwellers, but concurrent infection with HTLV-I was not found. Future epidemiological studies should identify individual risk factors and other communities at risk so that appropriate interventions can be planned.