First Report of Enterocytozoon hepatopenaei Infection in Pacific Whiteleg Shrimp (Litopenaeus vannamei) Cultured in Korea

SIMPLE SUMMARY: We here report the first detection of Enterocytozoon hepatopenaei (EHP) in cultured Pacific whiteleg shrimp (Litopenaeus vannamei) with a growth disorder in Korea. The histopathology, electron microscopy and DNA phylogeny indicated that the EHP is a unique strain first recorded in Korea. This finding highlights the need for closer monitoring and surveillance to control EHP in aquaculture to prevent disastrous economic losses. ABSTRACT: The consumption of cultured crustaceans has been steadily increasing, and Pacific whiteleg shrimp (Litopenaeus vannamei) are major cultivated invertebrates worldwide. However, shrimp productivity faces a variety of challenges, mainly related to outbreaks of lethal or growth retardation-related diseases. In particular, hepatopancreatic microsporidiosis caused by the microsporidian parasite Enterocytozoon hepatopenaei (EHP) is an important disease associated with growth retardation in shrimp. Here, we report the detection of EHP through histopathological, molecular and electron microscopy methods in the hepatopancreas of Pacific whiteleg shrimp with growth disorder in a South Korean farm. Phylogenetic analysis showed a clade distinct from the previously reported EHP strains isolated in Thailand, India, China and Vietnam. An EHP infection was not associated with inflammatory responses such as hemocyte infiltration. Although EHP infection has been reported worldwide, this is the first report in the shrimp aquaculture in Korea. Therefore, an EHP infection should be managed and monitored regularly for effective disease control and prevention.