Microsporidian Infection in the Trunk Muscle of Hatchery-bred Juvenile Spotted Halibut Verasper variegatus

Yokoyama, Hiroshi; Yokoyama, Fumihiko; Zhang, Jinyong; Tsuruoka, Kouta; Ogawa, Kazuo

doi:10.3147/jsfp.43.137

Cited by 6 publications

(7 citation statements)

References 9 publications

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“…RSB, and Microsporidium sp. SH (see also Yokoyama et al [25]). An unidentified microsporidian has been reported from Atlantic bluefin tuna (Thunnus thynnus) [26] that is distinguishable from Microsporidium sp.…”

Section: Discussionmentioning

confidence: 90%

Myxosporean and microsporidian infections in cultured Pacific bluefin tuna Thunnus orientalis in Japan

et al. 2010

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During the parasitological survey of cultured juvenile Pacific bluefin tuna (PBT) Thunnus orientalis in 2007 and 2008, two myxosporeans and one microsporidian were found. Morphological and molecular analysis showed that the heart-infecting and brain-infecting myxosporeans are identified as Kudoa shiomitsui and K. yasunagai, respectively. This is a new host record for both species. High prevalence of infection (77-100%) with K. shiomitsui was observed in October to December (1-2 months posttransfer to sea cages), whereas only a few fish were infected with K. yasunagai. A microsporidian observed as white ''cysts'' in the trunk muscle of PBT had a resemblance to Microsporidium seriolae, the causative parasite of beko disease in yellowtail. Phylogenetic analysis showed that the microsporidian from PBT is closely related to but distinct from several other muscle-infecting species such as M. seriolae, Microsporidium sp. RSB, and Microsporidium sp. SH. Additionally, the spore dimension (2.7 9 1.5 lm on average) was remarkably smaller than the others. These results suggest that the present microsporidian is an undescribed species and designated Microsporidium sp. PBT. Prevalence and intensity of infection with Microsporidium sp. PBT reached a maximum of 100% and 20 cysts/fish, respectively. Although pathogenic effects of the two Kudoa species on fish health remain unknown, the microsporidian could be of concern to PBT aquaculture due to unsightly cysts in the musculature, reducing the market value of the fish.

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Section: Discussionmentioning

confidence: 90%

Myxosporean and microsporidian infections in cultured Pacific bluefin tuna Thunnus orientalis in Japan

et al. 2010

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“…Several microsporidians that cause similar symptoms and show high genetic similarity with M. seriolae have been reported in other fish species such as red sea bream (Pagrus major), spotted halibut (Verasper variegatus), and Pacific bluefin tuna (Thunnus orientalis) (Bell et al, 2001;Yokoyama et al, 2008;Zhang et al, 2010). The sequences of ribosomal RNA (rRNA) operons of these microsporidians and M. seriolae shows slight differences in the internal transcribed spacer (ITS) regions, while the small and large subunit rRNA sequences are highly conserved.…”

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confidence: 74%

“…The genus Microsporidium is tentatively used for unclassified Microsporidia (Sprague, 1977). Close phylogenetic groups of M. seriolae are the genus Kabatana, Glugea, and Spraguea among others (Yokoyama et al, 2008).…”

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confidence: 99%

Development of Quantitative Real-time PCR and Loop-mediated Isothermal Amplification (LAMP) Assays for Detection of <i>Microsporidium seriolae</i>

et al. 2021

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Beko disease, caused by the Microsporidium seriolae infection, has been a problem in yellowtail aquaculture in western Japan. In recent years, severe cases of this disease have been confirmed, resulting in a significant decrease in product value due to mass mortality and residual cysts. Only polymerase chain reaction (PCR) assays have been reported so far as a detection method for the disease. In this study, quantitative real-time PCR (qPCR) and loop-mediated isothermal amplification (LAMP) methods have been optimized for M. seriolae detection in order to establish a more sensitive and rapid diagnosis. Target regions for each detection method were selected based on the nucleotide sequences obtained by the gene analysis of cysts in diseased fish. Primer sets for the qPCR and LAMP methods were designed, and the gene amplification efficiency of each method was evaluated. The results showed that the newly developed qPCR method could detect 1.4 copies of the target gene, and the LAMP method detected 100 copies within 15 minutes. In this study, the newly developed qPCR and LAMP assays were shown to be rapid and highly sensitive methods for quantitative detection of M. seriolae.

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“…A recent increase in parasitic diseases in Japanese aquaculture has been recognized as one of the most serious problems for the industry (Yanagida, Palenzuela, Hirae, Tanaka, Yokoyama & Ogawa 2008; Yokoyama, Yokoyama, Zhang, Tsuruoka & Ogawa 2008). Encephalomyelitis of cultured yellowtail, Seriola quinqueradiata Temminck & Schlegel, associated with an unidentified parasitic organism, has recently occurred in western Japan.…”

Section: Introductionmentioning

confidence: 99%

Molecular diagnosis of Myxobolus spirosulcatus associated with encephalomyelitis of cultured yellowtail, Seriola quinqueradiata Temminck & Schlegel

Yokoyama

Yanagida

Freeman

et al. 2010

Journal of Fish Diseases

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Mass mortality of cultured yellowtail, Seriola quinqueradiata, has recently been reported from fish farms in western Japan. Previous studies revealed that diseased fish were characterized by encephalomyelitis and presporogonic stages of a myxosporean-like parasite in the spinal cord. However, the parasite has remained unidentified because of the lack of mature stages being present. Thus, in the present study, analysis of the small subunit ribosomal DNA (18S rDNA) of the parasite as well as in situ hybridization (ISH) studies using histological sections of the infected tissue was conducted. The 18S rDNA of the myxosporean had higher sequence similarities with those of bile-duct-infecting myxosporeans rather than those infecting nervous tissues and was identified as Myxobolus spirosulcatus. The ISH using specific probes demonstrated that the DNA amplified was derived from the multinuclear organisms found in histological sections. A highly sensitive and specific PCR-based assay for M. spirosulcatus was developed, which revealed a high prevalence of infection in cultured yellowtail that exhibited the clinical signs of encephalomyelitis.

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Microsporidian Infection in the Trunk Muscle of Hatchery-bred Juvenile Spotted Halibut Verasper variegatus

Cited by 6 publications

References 9 publications

Myxosporean and microsporidian infections in cultured Pacific bluefin tuna Thunnus orientalis in Japan

Myxosporean and microsporidian infections in cultured Pacific bluefin tuna Thunnus orientalis in Japan

Development of Quantitative Real-time PCR and Loop-mediated Isothermal Amplification (LAMP) Assays for Detection of <i>Microsporidium seriolae</i>

Molecular diagnosis of Myxobolus spirosulcatus associated with encephalomyelitis of cultured yellowtail, Seriola quinqueradiata Temminck & Schlegel

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