Isolation of the Parasite Enterocytospora artemiae From Chinese Grass Shrimp (Palaemonetes sinensis)—First Report in Asia

Abstract

Chinese grass shrimp (Palaemonetes sinensis) is an economically important crustacean in Chinese aquaculture. Recently, we found that shrimp in Panjin city were infected with microsporidia, a group of fungi. The hepatopancreas of several infected shrimp showed white turbidity and pathological changes that negatively affected the health and appearance of the shrimp. Histopathology and transmission electron microscopy were used to examine the development of the parasite within its parasitophorous vacuole. Our results indicated that microsporidia developed asynchronously within the same parasitophorous vacuole. The spores were predominantly small, and rod or oval-shaped. The sizes of fresh spores were approximately 3.1 × 2.4 μm and fixed spores were 1.9 × 1.1 μm. The polar filament was isofilar with 5–6 coils and the thickness was 103.2 nm. Merogonial divisions occurred by binary fission and sporogonial division occurred by plasmotomy. The small subunit ribosomal DNA sequence (1295 bp) from the parasite was highly similar to the previously reported parasite Enterocytospora artemiae (99% nucleotide identity, JX915760). Using maximum likelihood to analyze the phylogenetic relationships, we found that this microsporidian should be grouped within Clade IV, an Enterocytospora-like clade, of the Microsporidia phylum. Based on this parasite’s life cycle characteristics, morphology, and small subunit ribosomal DNA sequence, the parasite described here is likely E. artemiae, which has previously only been described in Europe and North America. Thus, this is the first report of E. artemiae both in Asia and economically important shrimp.

Development of a Quantitative PCR Method for Specific and Quantitative Detection of Enterocytospora artemiae, a Microsporidian Parasite of Chinese Grass Shrimp (Palaemonetes sinensis)

“…Meanwhile, the qPCR method was used to detect EAM tissue tropism and the carriers in the culture environment. The tissue tropism detection found that the content in the hepatopancreas was the highest, indicating that it was the main location of EAM, which was consistent with previous research (Rode et al, 2013;Jiang et al, 2020). At the same time, EAM was also detected in the gut, gill, stomach and muscle, and the same results have been obtained with EHP (Santhoshkumar et al, 2017;Cheng et al, 2018).…”

“…MT 645708) had 94% shared homology with the SSU rRNA gene of Globulispora mitoporans (GenBank No. KT762153), which shared more than 85% identity with five other species (Jiang et al, 2020). Therefore, we selected a specific target to modify the SYBR Green I qPCR detection method to detect microsporidia in P. sinensis.…”

“…It was considered as an obligate parasite of Artemia that was confined to Europe and America (Rode et al, 2013). However, in 2020, it was found that this microsporidian had spread to Asia and was infecting the economically important Chinese grass shrimp, Palaemonetes sinensis (Jiang et al, 2020). EAM mainly parasitizes the hepatopancreas of P. sinensis (Jiang et al, 2020).…”

“…However, in 2020, it was found that this microsporidian had spread to Asia and was infecting the economically important Chinese grass shrimp, Palaemonetes sinensis (Jiang et al, 2020). EAM mainly parasitizes the hepatopancreas of P. sinensis (Jiang et al, 2020). Serious EAM infections lead to hepatopancreatic lesions and greatly reduce the vitality of P. sinensis.…”

“…Therefore, it is necessary to establish a rapid and accurate method to detect these parasites. Currently, only conventional PCR methods are used to detect EAM (Rode et al, 2013;Jiang et al, 2020). However, conventional PCR has low sensitivity and cannot be used for accurate, quantitative detection of EAM or its parasitic activity in host tissues.…”