Kudoa septempunctata have been reported as a causative agent for acute transient gastrointestinal troubles after eating raw olive flounder (Paralichthys olivaceus). It raised public health concerns and quarantine control in several countries. Quantitative evaluation on viability of K. septempunctata is crucial to develop effective chemotherapeutics against it. A cytometry using fluorescent stains was employed to assess effect of three compounds on viability of K. septempunctata. Epigallocatechin gallate reduced markedly viability of K. septempunctata at 0.5 mM or more, and damaged K. septempunctata spores by producing cracks.

Kudoa septempunctata, a myxozoan, has been identified as the causative agent of foodborne illnesses associated with the consumption of raw olive flounder. To develop effective control methods against this parasite, fundamental research—including viability determination, transcriptome analysis, and antigenicity assessment of K. septempunctata myxospores—is required. This research necessitates the purification of the parasites. Sequential trypsin digestion, followed by density gradient purification, was performed to isolate the K. septempunctata myxospores. Further purification was achieved through fluorescence-activated cell sorting at a concentration of 106 to 107 myxospores/ml. The results demonstrated that the combination of trypsin digestion and density gradient methods consistently produced approximately 40 times more viable myxospores than the density gradient method alone. Additionally, the fluorescence-activated cell sorting method enhanced the purity of the myxospores by approximately 10 %. The procedures described in this study will support research (such as RNA-sequencing, proteomics, vaccine antigen preparation) aimed at developing control methods for K. septempunctata including the fundamental research.