Advancements in Diagnostics Enhance Global Monitoring of Strongyloidiasis

Researchers at the Liverpool School of Tropical Medicine have introduced an innovative diagnostic tool aimed at improving the global monitoring of strongyloidiasis, a neglected tropical disease. This new method effectively distinguishes between two closely related species of threadworms: Strongyloides stercoralis, which primarily affects humans, and Strongyloides fuelleborni fuelleborni, typically found in non-human primates and increasingly associated with zoonotic transmission.

The findings have been published in The Journal of Infectious Diseases. Historically, molecular surveillance has relied on a less precise testing method that failed to differentiate between these two species, leading to potential misdiagnoses and an underestimation of zoonotic cases. The newly developed duplex real-time PCR (rtPCR) test utilizes mitochondrial DNA to accurately identify each species from clinical samples, similar to the methodologies used for COVID-19 testing.

Strongyloidiasis is listed as one of the 21 neglected tropical diseases by the World Health Organization, with ongoing diagnostic challenges limiting global efforts to map its spread and mitigate its effects. The lead researcher on the study emphasized that this rtPCR tool addresses a significant gap in current diagnostic capabilities, enabling better monitoring of zoonotic transmission and facilitating targeted interventions, particularly in areas where both humans and non-human primates overlap.

Laboratory assessments of the diagnostic tool demonstrated high specificity and sensitivity in detecting parasite DNA. When applied to 96 clinical samples from the UK and Italy, the assay successfully identified 36 cases of S. stercoralis, 17 cases of S. f. fuelleborni, and two instances of co-infection.

The researchers recommend a two-step procedure for diagnostics: initially screening for the presence of Strongyloides with a broad test, followed by species-specific confirmation using the new rtPCR test. This approach is essential for improving the identification of both imported and locally acquired infections in regions where strongyloidiasis is often overlooked.

One of the co-authors of the study, a medical parasitologist, indicated that there is a push for the broader application of this diagnostic assay in routine disease monitoring within the UK and internationally. This would enhance understanding of travel-related infections and improve public health guidance.

Furthermore, the research presents a framework for refining diagnostic practices across other neglected tropical diseases that may have zoonotic implications, potentially leading to broader public health benefits.