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

## TL;DR

This study detects and genetically characterizes Enterocytozoon hepatopenaei in giant freshwater prawns imported to South Korea from India and Vietnam.

## Contribution

The study reports the first detection of EHP in Macrobrachium rosenbergii imported to South Korea and reveals new genetic diversity patterns.

## Key findings

- EHP was detected in 13.3% of samples from India and 71.4% from Vietnam.
- Genetic analysis of EHP from M. rosenbergii revealed greater diversity compared to Penaeus vannamei.
- SWP 1 and ITS-1 regions showed distinct groupings, some closely related to P. vannamei EHPs.

## Abstract

Enterocytozoon hepatopenaei (EHP) is an intracellular parasite that causes substantial economic losses to the global shrimp industry. Although penaeid shrimps are particularly vulnerable to EHP infection and have been extensively studied, Macrobrachium rosenbergii (giant freshwater prawn), another important species widely farmed in warm-climate regions, is also affected by this pathogen. Despite the increasing global incidence of EHP infection in M. rosenbergii, studies on this species remain limited compared to those on penaeid shrimps. Here, we monitored the EHP infection in M. rosenbergii imported from India and Vietnam to South Korea and conducted genetic analyses to better characterize its genetic diversity.

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.