RNAscope: a novel method for the detection ofova in canine liver.

Abstract

Canine schistosomiasis caused bycan lead to severe morbidity and eventual mortality, in part due to the deposition of fluke ova in the liver and gastrointestinal tract, which promotes an influx of peri-ova inflammatory cells. Although fluke eggs can be identified in H&E-stained histologic sections, cases exist in which only fragments of the ova persist, or the egg is obscured by inflammatory infiltrates, which can confound definitive histologic diagnosis. Unfortunately, antibodies specific toare not commercially available for immunohistochemical labeling. Therefore, we aimed to use an RNA in situ hybridization strategy to fluorescently labelova. Using the18S rRNA sequence, we developed an RNA probe and validated its performance on archival formalin-fixed, paraffin-embedded canine tissue. A positive signal was observed for all identifiable ova, fragmented and whole. Use of this methodology could aid understanding of the pathogenesis ofinfection in dogs. This technique augments standard diagnostic methodology, enabling spatial colocalization of fluke ova and inflammatory infiltrates when using fluorescent techniques.