From past to present: opportunities and trends in the molecular detection and diagnosis of Strongyloides stercoralis

Abstract

Strongyloides stercoralis is a soil-transmitted helminth that is mainly found in the tropical and subtropical regions and affects approximately 600 million people globally. The medical importance of strongyloidiasis lies in its capacity to remain asymptomatic and chronically unnoticed until the host is immunocompromised. Additionally, in severe strongyloidiasis, hyperinfection syndrome and larva dissemination to various organs can occur. Parasitological techniques such as Baermann-Moraes and agar plate culture to detect larvae in stool samples are the current gold standard. However, the sensitivity might be inadequate, especially with reduced worm burden. Complementing parasitological techniques, immunological techniques including immunoblot and immunosorbent assays are employed, with higher sensitivity. However, cross-reactivity to other parasites may occur, hampering the assay’s specificity. Recently, advances in molecular techniques such as polymerase chain reaction and next-generation sequencing technology have provided the opportunity to detect parasite DNA in stool, blood, and environmental samples. Molecular techniques, known for their high sensitivity and specificity, have the potential to circumvent some of the challenges associated with chronicity and intermittent larval output for increased detection. Here, as S. stercoralis was recently included by the World Health Organization as another soil-transmitted helminth targeted for control from 2021 to 2030, we aimed to present a review of the current molecular techniques for detecting and diagnosing S. stercoralis in a bid to consolidate the molecular studies that have been performed. Upcoming molecular trends, especially next-generation sequencing technologies, are also discussed to increase the awareness of its potential for diagnosis and detection. Improved and novel detection methods can aid in making accurate and informed choices, especially in this era where infectious and non-infectious diseases are increasingly commonplace. Graphical Abstract

Strongyloides infection screening in transplant candidates: What is the best strategy?

“…In recent years, there has been an increasing number of studies evaluating molecular techniques in the diagnosis of human strongyloidiasis 28–31 . In general, the limitation in the evaluation of the results obtained in these studies concerns the use of in‐house extraction methods, as well as variations in strategies for DNA amplification.…”

Epidemiological, Clinical and Laboratory Features of Strongyloidiasis in 69 Attendees at a French Outpatient Clinic

“…Moreover, these techniques are operator-independent with respect to the interpretation of the results and, therefore, overcome the worldwide growing issue of the availability of well-trained technicians for microscopy diagnosis. Se ranges from 17% to 100%, and Sp ranges from 76.7% to 100%, according to the nature of the genetic marker, the primer used, and the type of PCR [ 22 ]. In most studies, DNA was extracted from fecal specimens, but the use of urine and particularly of serum displayed interesting perspectives [ 23 ].…”