The conventional method of detecting Strongyloides stercoralis in fecal samples has poor diagnostic sensitivity. Detection of Strongyloides-specific antibodies increases the sensitivity; however, most tests are ELISAs that use parasite extract which may cross-react with the sera of other helminth infections. To improve the serological diagnosis of strongyloidiasis, this study aimed at developing a sensitive and specific lateral flow rapid dipstick test. Two recombinant proteins, recombinant NIE (rNIE) and recombinant Ss1a (rSs1a), were used in preparing the dipstick, with gold-conjugated antihuman IgG4 as detector reagent. In parallel, the corresponding ELISA was performed. Both assays demonstrated diagnostic sensitivity of 91.3% (21/23) when tested with serum samples of patients with Strongyloides infection, and 100% specificity with 82 sera of asymptomatic (healthy) and those with other parasitic infections. The ELISA and dipstick test results were positively correlated to each other (r = 0.6114, P = 0.0019). The developed lateral flow dipstick test may improve the serodiagnosis of strongyloidiasis and merit further validation studies.

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is a human parasite that can cause a long-term infection. In immunosuppressed patients, strongyloidiasis may be fatal when there is overwhelming autoinfection resulting in the migration of large numbers of larvae through many organs. Definitive diagnosis is still a challenge, and a combination of symptoms, microscopic identification, and serology test results are often used to arrive at a clinical decision. However, intermittent larval excretion, low parasite burden, and occult infections are challenges with parasitological diagnosis of infection with . Meanwhile, serologic tests using immunoglobulin G and parasite antigen extract have problems of cross-reactivity with other helminthic infections. Recombinant antigen-based serodiagnosis is a good alternative to overcome the laboratory diagnostic issues. Herein, we report on the isolation of cDNA clone encoding an antigen of potential diagnostic value identified from immunoscreening of a cDNA library. The translated protein had highest similarity to immunoglobulin-binding protein 1. The recombinant antigen produced, rSs1a, was assessed using western blot and enzyme-linked immunosorbent assay. The latter showed 96% diagnostic sensitivity and 93% specificity; thus, rSs1a has good potential for use in serodiagnosis of human strongyloidiasis.

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