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

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