Closing the diagnostic gap in male genital schistosomiasis (MGS): current detection tools and novel strategies

Abstract

Male genital schistosomiasis (MGS), a gender-specific manifestation of urogenital schistosomiasis and neglected tropical disease, typically results from the entrapment of Schistosoma haematobium eggs within the male genital tract. Across the world, there are no current and accurate estimates of the burden of MGS, due to disease underreporting primarily from diagnostic challenges and a lack of general awareness within the health system. Diagnostic methods for MGS are extremely limited. Conventionally, semen microscopy for Schistosoma ova is used though this technique suffers from low sensitivity and lacks protocol standardization. The introduction of molecular diagnostics, such as polymerase chain reaction (PCR), has partly helped overcome this challenge of low sensitivity, though may not be suitable for use in resource-constrained settings. To address these challenges, in this review, we propose a two-step diagnostic algorithm for MGS in accordance with recent WHO guidelines, consisting of a high sensitivity serological test followed by a high specificity test (microscopy or molecular assay, dependent on setting). Further investigation is required into standardization of sample collection, processing, storage, and analysis in order to identify an evidence-based optimal diagnostic pipeline. New diagnostic tools are needed such as isothermal molecular assays, alongside optimization for semen analysis, which may alleviate barriers to diagnosis and present opportunities for integration with other sexual and reproductive health screening. These areas of future investigation underpin the development of a suitable diagnostic pipeline, as the continued neglect of MGS and its underdiagnosis presents a threat to the goal of elimination of schistosomiasis as a public health problem.

Keywords: Schistosoma haematobium; diagnostics; male genital schistosomiasis; semen.