Accuracy of Five Serologic Tests for the Follow up of Strongyloides stercoralis Infection

Abstract

BackgroundTraditional faecal-based methods have poor sensitivity for the detection of S. stercoralis, therefore are inadequate for post-treatment evaluation of infected patients who should be carefully monitored to exclude the persistence of the infection. In a previous study, we demonstrated high accuracy of five serology tests for the screening and diagnosis of strongyloidiasis. Aim of this study is to evaluate the performance of the same five tests for the follow up of patients infected with S. stercoralis.MethodsRetrospective study on anonymized, cryo-preserved samples available at the Centre for Tropical Diseases (Negrar, Verona, Italy). Samples were collected before and from 3 to 12 months after treatment. The samples were tested with two commercially-available ELISA tests (IVD, Bordier), two techniques based on a recombinant antigen (NIE-ELISA and NIE-LIPS) and one in-house IFAT. The results of each test were evaluated both in relation to the results of fecal examination and to those of a composite reference standard (classifying as positive a sample with positive stools and/or at least three positive serology tests). The associations between the independent variables age and time and the dependent variable value of serological test (for all five tests), were analyzed by linear mixed-effects regression model.ResultsA high proportion of samples demonstrated for each test a seroreversion or a relevant decline (optical density/relative light units halved or decrease of at least two titers for IFAT) at follow up, results confirmed by the linear mixed effects model that showed a trend to seroreversion over time for all tests. In particular, IVD-ELISA (almost 90% samples demonstrated relevant decline) and IFAT (almost 87%) had the best performance. Considering only samples with a complete negativization, NIE-ELISA showed the best performance (72.5% seroreversion).ConclusionsSerology is useful for the follow up of patients infected with S. stercoralis and determining test of cure.

Systemic Cytokine Profiles in Strongyloides stercoralis Infection and Alterations following Treatment

“…Follow-up was performed at 6 months following recruitment and treatment. Strongyloides infection was diagnosed by the presence of IgG antibodies to the recombinant antigen, NIE, as de-scribed previously (13,14). This was further confirmed by specialized stool examination with nutrient agar plate cultures (15).…”

Microbial Translocation Associated with an Acute-Phase Response and Elevations in MMP-1, HO-1, and Proinflammatory Cytokines in Strongyloides stercoralis Infection

“…stercoralis infection was diagnosed by the presence of IgG antibodies to the 31-kDa recombinant antigen (termed NIE), as described previously (47,48). This was further confirmed by specialized stool examination with nutrient agar plate cultures (49).…”

Severe Anemia and Lung Nodule in an Immunocompetent Adopted Girl with Strongyloides stercoralis Infection

“…IFAT was repeated about 7 months after treatment (because the titer decreases slowly through time 13 ) and showed a 5-fold drop in titer, demonstrating the response to therapy, confirmed by the normal eosinophil count and the negative APC and qPCR. However, we have planned a further follow-up visit 1 year after treatment.…”