Detection and Genetic Characterization of Enterocytozoon hepatopenaei in Giant Freshwater Prawn (Macrobrachium rosenbergii) Imported into South Korea

This study investigated <i>Macrobrachium rosenbergii</i> imported from India (15 batches, <i>N</i> = 180) and Vietnam (7 batches, <i>N</i> = 84) between 2023 and 2024, for <i>Enterocytozoon hepatopenaei</i> (EHP) monitoring and genetic analysis. Polymerase chain reaction assays detected EHP in 13.3% (2/15) and 71.4% (5/7) samples from India and Vietnam, respectively. The sequence of the small subunit ribosomal ribonucleic acid region of the EHPs isolated from <i>M. rosenbergii</i> showed no significant differences from those available in GenBank. Interestingly, spore wall protein (SWP) 1 region analysis revealed that <i>M. rosenbergii</i> EHPs could be divided into three groups, some of which were closely related to <i>Penaeus vannamei</i> EHPs. Similarly, the internal transcribed spacer-1 (ITS-1) region analysis divided <i>M. rosenbergii</i> EHPs into two groups, with some showing close relationships with <i>P. vannamei</i> EHPs. Phylogenetic analyses based on the SWP 1 and ITS-1 regions suggested that EHPs infecting <i>M. rosenbergii</i> exhibited greater genetic diversity than those infecting <i>P. vannamei</i>. This study provides the first report of EHP detection in <i>M. rosenbergii</i> imported from India and Vietnam to South Korea. Further genome-based analyses are necessary for a comprehensive genetic characterization of EHPs infecting <i>M. rosenbergii</i> from various geographical regions.