Identification and isolation of a spiroplasma pathogen from diseased freshwater prawns, Macrobrachium rosenbergii, in China: A new freshwater crustacean host

An epidemic of hepatopancreatic necrosis disease (HPND) with a high mortality rate (40%-50%) recently occurred in the cultured Chinese mitten crab, Eriocheir sinensis, which is a very important economic crustacean species in China. Histology revealed infection by a microsporidian parasite within the cytoplasm of the epithelial cells of the hepatopancreas. Numerous discrete inclusions in the infected cells and presumably free parasite spores were also observed. By negative staining using electron microscopy, a typical morphology of spores was observed with a protuberant front of the anchoring disc. Infection was confined to the epithelial cells of the hepatopancreas, with no other organ implicated. By sequencing the PCR products using specific primers based on conserved regions of microsporidian small subunit (18S) ribosomal DNA, it was revealed that the parasite from HPND ponds had 99% sequence identity to that of Hepatospora eriocheir. Phylogentic analysis also placed the microsporidian in the same lineage as H. eriocheir. This study reported the first case of widespread infections of H. eriocheir associated with HPND found in the pond-reared Chinese mitten crab, E. sinensis. The description of microsporidian in this important commercial host is fundamental for future consideration of factors affecting stock health and sustainability.

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“…The grid was air‐dried before examination using a transmission electron microscope (Hitachi H‐7650) (Liang et al . ).…”

Section: Methodsmentioning

confidence: 97%

First case of hepatopancreatic necrosis disease in pond‐reared Chinese mitten crab, Eriocheir sinensis, associated with microsporidian

Ding

Meng

Liu

et al. 2016

Journal of Fish Diseases

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“…During the experiment, the crabs were fed with commercial feed, and water was changed every day. Eighty crabs were divided into two groups and used for experimental infection: 40 crabs were inoculated with 0.2 ml (10 8 cells/ ml) of S. eriocheiris each, and the other 40 crabs were inoculated with 0.2 ml of vacant R2 medium as the control [9,16,50,51]. Phase contrast microscopy and transmission electron microscopy using blood smears and the negative staining method were used to examine the progression of the S. eriocheiris infection [9,10,14].…”

Section: Methodsmentioning

confidence: 99%

“…eriocheiris has been identified as the causative pathogen of TD in aquatic crustaceans such as E. sinensis [7e10], Procambarus clarkia [14], Penaeus vannamei [15], and Macrobrachium rosenbergii [16]. Spiroplasma belongs to one of the cell-wall-free mollicutes, has a typical helical structure and the capacity to be motile, is associated with insects, ticks, plants, and crustaceans, and causes Spiroplasma infection, morbidity, and mortality in many species [11e13,17].…”

Section: Introductionmentioning

confidence: 99%

Identification and comparative analysis of the Eriocheir sinensis microRNA transcriptome response to Spiroplasma eriocheiris infection using a deep sequencing approach

Meng

et al. 2012

Fish & Shellfish Immunology

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“…The grid was air‐dried before examination with a transmission electron microscope (Hitachi H‐7650) (Liang et al . ).…”

Section: Methodsmentioning

confidence: 97%

Development of In situ hybridization and real‐time PCR assays for the detection of Hepatospora eriocheir, a microsporidian pathogen in the Chinese mitten crab Eriocheir sinensis

Ding

Chen

Lin

et al. 2016

Journal of Fish Diseases

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A microsporidian parasite, Hepatospora eriocheir, is an emerging pathogen for the Chinese mitten crab Eriocheir sinensis. Currently, there is scant information about the way it transmits infection in the crustacean of commercial importance, including its pathogenesis, propagation and infection route in vivo. In this study, chromogenic in situ hybridization (ISH) and quantitative real-time PCR (qPCR) assays were developed to address this pressing need, and we provided an advance in the detection methods available. Pathogens can be seen in situ with associated lesions using ISH. Positive hybridization signals were noted inside the epithelial cells of the hepatopancreas, and putative free parasite spores were observed within the tubule lumen, which were associated with lesions detected by electron microscopy and haematoxylin and eosin (H&E) analysis. qPCR allows the determination of parasite loads in infected tissues, which is important for understanding disease progression and transmission. The hepatopancreas displayed the biggest statistical copy numbers among different tissues of infected crabs, confirming a tissue-specific pathogen infection characteristic. The qPCR assay also proved to be suitable for the diagnosis of asymptomatic carrier crabs. Combination of the two methods could facilitate the study of H. eriocheir infection mechanism in E. sinensis, enhance the early diagnosis of the pathogen and improve the management of microsporidian diseases in commercial crustaceans.

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Identification and isolation of a spiroplasma pathogen from diseased freshwater prawns, Macrobrachium rosenbergii, in China: A new freshwater crustacean host

Cited by 56 publications

References 28 publications

First case of hepatopancreatic necrosis disease in pond‐reared Chinese mitten crab, Eriocheir sinensis, associated with microsporidian

First case of hepatopancreatic necrosis disease in pond‐reared Chinese mitten crab, Eriocheir sinensis, associated with microsporidian

Identification and comparative analysis of the Eriocheir sinensis microRNA transcriptome response to Spiroplasma eriocheiris infection using a deep sequencing approach

Development of In situ hybridization and real‐time PCR assays for the detection of Hepatospora eriocheir, a microsporidian pathogen in the Chinese mitten crab Eriocheir sinensis

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