Serological assays for the diagnosis of Strongyloides stercoralis infection: a systematic review and meta-analysis of diagnostic test accuracy

Abstract

The standard method for the diagnosis of Strongyloides stercoralis, stool examinations, is inconvenient and, therefore, serological methods have been proposed. This study aimed to evaluate the accuracy of serological assays for the diagnosis of strongyloidiasis using a systematic review and meta-analysis model. Four electronic databases were reviewed. We used a random effects model and 95% CIs to determine the overall sensitivity, specificity and diagnostic odds ratio (DOR). Heterogeneity was intended with Cochran Q χ2 test and I2 statistic. The accuracy of serological assays resulted in a sensitivity of 71.7% (95% CI: 56.07 to 83.4%), a specificity of 89.9% (95% CI: 80.8 to 94.9%) and a DOR of 22.5 (95% CI: 10.8 to 46.9). The forest plot showed high heterogeneity regarding sensitivity (I2=90.4%, 95% CI: 87.4 to 93.3%; Q=228.1, p=0.000) and specificity (I2=98.9%, 95% CI: 98.8 to 99.1%; Q=2066.4, p=0.000). Fagan's nomogram showed that the probability of someone having the infection and with a positive test result was 49%. Deeks' funnel plots showed no evidence of potential publication bias for the studies (p=0.26). The current review suggests that serological techniques have acceptable sensitivity and specificity and therefore can be recommended for the screening of S. stercoralis infection.

Diagnostic accuracy of somatic and excretory−secretory antigens from Strongyloides venezuelensis infective larvae for the immunodiagnosis of human strongyloidiasis

“…Strongyloidiasis is a human parasitic infection that is still underdiagnosed and underestimated, resulting in a serious public health problem worldwide. Even though the detection of antibodies cannot be useful for post-treatment monitoring, detection of IgG antibodies by ELISA is preferred for the serodiagnosis of strongyloidiasis due to its high sensitivity, reproducibility and its capacity to work with high number of samples, being a powerful tool for both the clinical diagnosis and seroepidemiological studies (Kalantari et al, 2020). However, ELISA requires classify a result as positive or negative and the most used method to choose a cutoff value is the ROC curve analysis, where the AUC determines the inherent ability of the test to discriminate between the diseased and healthy populations (Eusebi, 2013).…”

“…A meta-analysis published by Kalantari et al (2020) about serodiagnostic test accuracy using antigens from different Strongyloides species showed that antigens from S. venezuelensis were more sensitive and specific than antigens from S. stercoralis or S. ratti, and proposed that heterologous antigens from S. venezuelensis are an excellent alternative for the serodiagnosis of human strongyloidiasis. The results of the present study confirm the potential use of these antigens obtained from S. venezuelensis iL3 which showed remarkable AUC values over 0.99, being considered with excellent diagnostic accuracy for the detection of IgG anti-Strongyloides antibodies.…”

“…These tests include indirect immunofluorescence assay, gelatin particle agglutination, enzyme-linked immunosorbent assay (ELISA) and western-blot (Requena-Méndez et al, 2013), but the most widely used test is the ELISA whose main advantages are its high sensitivity and its usefulness in seroepidemiological studies (Nunes et al, 2018;Casado et al, 2019). However, due to limitations in obtaining antigens from S. stercoralis, other species such as Strongyloides ratti and S. venezuelensis have been used as a good heterologous source of antigens to develop these mentioned immunoassays (Kalantari et al, 2020). S. ratti and S. venezuelensis are parasites from rats, but also are capable of infecting other rodents, such as mice and gerbils; whereas hosts infected with S. ratti excrete both eggs and earlystage larvae, hosts infected with S. venezuelensis excrete early stage eggs with the faeces.…”

Tropical Infections in the Context of Kidney Transplantation in Latin America

“…86 Because the sensitivity of this method is not ideal, serological assays and molecular biology techniques (PCR) have been suggested as alternatives or additional tools. 87,88 Treatment is preferably accomplished with ivermectin for 2 days, and a second course can be indicated 1 or 2 weeks later. In patients with severe forms, treatment should be continued until symptoms improve and serial stool samples are negative for 2 weeks.…”

Systemic profile of immune factors in an elderly Italian population affected by chronic strongyloidiasis

“…The traditional microscopic detection of larvae in faeces has unsatisfactory sensitivity; similarly, molecular detection of S. stercoralis DNA in stools by PCR is still considered inadequate for screening purposes [7]. Higher sensitivity can be achieved using serological methods, although there are some concerns about the specificity, particularly when used in endemic areas, due to possible cross-reactions with other nematodes [8,9].…”