Applicability of FLOTAC technique in recovering equine strongyle larvae in the pasture: A comparison study.

The FLOTAC technique represents a highly sensitive method for the isolation of oocysts, eggs, and larvae of parasites in faeces. This assay could be used for detecting free-living stages of nematodes in the pasture but no attempt has been assessed so far. Therefore, the performance of FLOTAC technique for isolating infective larvae of nematodes in the environment was investigated and compared with the spontaneous sedimentation (SST) and centrifugal sedimentation (CST) techniques. The study was conducted in a horse farm located in northeastern Brazil, where the occurrence of strongyle larvae had been previously reported. Pasture samplings were collected monthly from January to May 2016 in a 376 m crop area harvested with the Guinea grass Panicum cultivar Massai. The recovery of third-stage larvae (L3) was performed using the FLOTAC, SST and CST techniques. Values of Cohen's kappa coefficient, sensitivity, specificity, positive and negative predictive values, and accuracy of each technique were assessed. Although strongyle larvae were evenly detected, with the FLOTAC technique yielded the highest number of positive samples (i.e., 41%, 41/100, p < .0001). The main parasites isolated belonged to the Cyathostominae and Strongylinae subfamilies. Based on these results, the FLOTAC technique should be considered as practical and safe method for the isolation of nematode larvae in the pasture, thus opening a new potential use for this tool in the field.