Detection of Echinococcus granulosus sensu lato microRNAs in cystic echinococcosis patients: An exploratory study using quantitative PCR and digital PCR

Background: Cystic echinococcosis (CE) is a zoonosis caused by the larval stage of Echinococcus granulosus sensu lato (s.l.). The adult parasite typically resides in the intestine of canids, while the larval stage, a fluid-filled cyst, primarily resides in the liver and lungs of ungulates and humans. The diagnosis of abdominal CE in humans is mainly based on ultrasound (US) complemented by serology, but both techniques present limitations. Therefore, new diagnostic methods are needed. MicroRNAs (miRNAs) are potential suitable biomarkers for parasitic diseases, as well as for the diagnosis and cyst staging of CE. The objective of this study was to evaluate the presence of three E. granulosus s.l. miRNAs (egr-let-7-5p, egr-miR-10a-5p, and egr-miR-71-5p) in the serum of CE patients using novel TaqMan-based quantitative PCR (qPCR) and digital PCR (dPCR) assays. Methodology/Principal findings: Serum samples from 25 patients with CE, 10 patients with non-CE hepatic lesions, and 10 patients with other parasitic infections were collected. In addition, four cyst fluids were also obtained. Total small RNAs were extracted, reverse-transcribed into cDNA, and amplified. Conclusions: In conclusion, although this study’s explorative nature and the limited sample size, the detection of E. granulosus s.l. miRNAs in the serum of CE patients proved feasible, potentially supporting the medical decision-making process in association with US for CE diagnosis. Author summary: Cystic echinococcosis (CE) is a parasitic disease caused by Echinococcus granulosus s.l. The adult parasite typically resides in the intestine of canids, while the larval stage, a fluid-filled cyst, primarily resides in the liver and lungs of intermediate hosts (ungulates and humans). The diagnosis of abdominal CE mainly relies on ultrasound (US) and serological tests. However, the former is operator-dependent and the latter is not standardized. This study evaluated the presence of three E. granulosus s.l. microRNAs (small non-coding RNA molecules that regulate gene expression) in serum samples of CE patients as possible new diagnostic biomarkers.