Survey of Strongyloides papillosus Infection in Goats and Sheep in Part of China Using RAA-LFD Assay.

Strongyloidiasis caused by Strongyloides papillosus is a significant parasitic disease affecting the health and productivity of small ruminants globally. In this study, a novel recombinase-aided amplification (RAA) combined with lateral flow dipstick (LFD) assay was developed and validated for the rapid and specific detection of S. papillosus infection in goats and sheep, targeting the 18S ribosomal RNA (18S rRNA) gene. A total of 815 fecal samples were collected from nine provinces in China, encompassing major goats and sheep production regions. The RAA-LFD assay exhibited high sensitivity, with a minimum detection limit of 15 eggs per gram (EPG) of feces. Clinical fecal examination yielded a positive rate of 62.30% (433/695), while the RAA-LFD assay achieved a positive rate of 58.28% (475/815), indicating that the diagnostic accuracy of the RAA-LFD assay is consistent with that of fecal examination. Compared with conventional fecal examination, the RAA-LFD assay offers superior rapidity, portability, and sensitivity, presenting a valuable diagnostic tool for large scale epidemiological surveillance and point-of-care applications, particularly in resource constrained environments.