• Journal of fish pathology
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• v.35 no.2
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• pp.231-239
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• 2022

In this study, imported ornamental goldfish (Oranda and black moor) with high mortality was investigated with histopathological analysis. Fishes showed clinical symptoms characterized by gill necrosis and cumulative mortality ranging from 60% to 90% within a month after import from Thailand and China in 2021. CyHV-2 was detected in gill, kidney, spleen and liver of goldfishes. Histopathological analysis revealed epithelial necrosis, intranuclear inclusion bodies associated with viral symptoms in epithelial cell, macrophage infiltration and vacuolation in secondary lamella. In addition, disseminated granuloma formation was observed in various organs such as kidney, heart and mesenchymal membranes. These lesions refer to coinfections with CyHV-2 and other pathogens that cause chronic inflammation, which leads to mortality. Therefore, early disease monitoring needs to reduce the mortality when ornamental goldfish is imported.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.4
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• pp.383-388
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• 2018

Goldfish hematopoietic necrosis (GHN) affects hematopoietic organs and causes high mortality in goldfish. The causative agent of GHN is cyprinid herpesvirus 2 (CyHV-2). The purpose of this study was to detect CyHV-2 in ornamental cyprinid fish. CyHV-2 monitoring was conducted on a monthly basis for 1 year using goldfish Carassius auratus and pearlscale goldfish Carassius auratus that had been cultured at a domestic aquafarm and imported from Singapore, respectively. The results of polymerase chain reaction (PCR) assays using specific primers for the CyHV-2 helicase gene showed that 27.8% of goldfish and 33.3% of pearlscale goldfish were positive for CyHV-2. No cytophatic effects were detected in koi fin or common carp brain cells inoculated with tissue homogenates from either fish. Our data provides the useful data for establishing future quarantine and disinfection policies.

• Fisheries and Aquatic Sciences
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• v.22 no.2
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• pp.5.1-5.9
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• 2019

Background: Live fish import may lead to the unintended introduction of pathogens. We examined the monthly distribution of microbial pathogens in ornamental finfish imported into South Korea over a 6-month period. Results: Vibrio alginolyticus was detected in one lemon damsel in June and July; V. vulnificus was detected in one lemon damsel, one caerulean damsel, and one pearl-spot chromis and one ocellaris clownfish in July, April, and May, respectively; Photobacterium damselae was detected in one ocellaris clownfish and one caerulean damsel in June and July, respectively; V. anguillarum was detected in one pearl-spot chromis in February; V. harveyi was detected in one ocellaris clownfish and two mandarin fish in February and April, respectively; Yersinia ruckeri was detected in a pearlscale goldfish group in June and July and in two colored carp groups in July; and Lactococcus garvieae was detected in a lemon damsel group and a sutchi catfish group in July and May, respectively. European catfish virus, the only viral pathogen detected, was found in two sutchi catfish groups in May. Conclusion: This study is the first to identify pathogenic species and the presence or absence of pathogens (non-quarantine diseases) in imported ornamental finfish. These results demonstrate that various pathogens with the potential to harm indigenous fish populations can accompany ornamental finfish imported into South Korea.

• Fisheries and Aquatic Sciences
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• v.26 no.7
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• pp.437-446
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• 2023

Cyprinids are popular species for aquaculture worldwide, with Asia being a significant contributor to their production. In Korea, common carp (Cyprinus carpio), koi carp (Cyprinus rubrofuscus), and goldfish (Carassius auratus) are cultivated domestically and imported for ornamental or human consumption purposes. Among the viruses that infect cyprinids, cyprinid herpesvirus-2 (CyHV-2), koi herpesvirus (KHV, also known as cyprinid herpesvirus-3), and carp edema virus (CEV) are of particular concern as they cause substantial economic losses to the aquaculture industry. In this study, we investigated these viruses in both of domestic and imported cyprinids. Our results revealed that CyHV-2 was only detected in imported goldfish from Thailand. To further investigate the genetic characteristics of them, the marker A region was analyzed. Despite belonging to the same cluster with isolates from China, France, Poland, and Israel, CyHV-2 detected in this study showed distinct differences in their repetitive sequence sizes. Furthermore, two different forms of KHV/CEV coinfection were identified from domestic koi carp, both of which exhibited typical symptoms. Phylogenetic analysis showed that one KHV isolate (ScKc-2105-K) was of the Asian type and closely related to isolates from Japan, Indonesia, Belgium, Taiwan, and China. Two CEV isolates (ScKc-2105-CE and GhKc-2207-CE) be- longed to the IIa type and showed high similarity with isolates from the USA, France, and Korea. Notably, koi carp injected with cultured KHV (ScKc-2105-K) showed 78.0% cumulative mortality within 14 days post-injection (dpi). Our findings support the importance of regular surveillance of viral diseases in cyprinids.

• Journal of fish pathology
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• v.30 no.2
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• pp.89-96
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• 2017

The majority of freshwater ornamental fish are imported and distributed domestically, causing high risk of exposure to exotic pathogens and drug resistant bacteria in Korea. Aeromonas hydrophila is known as a common species of fresh water bacteria and opportunistic fish pathogen, as well as a species causing zoonotic infection. In this study, we isolated motile aeromonads from various imported freshwater ornamental fish and studied the characters of the isolates. Imported freshwater ornamental fish were purchased on day 1 after the fish were deposited in the aquarium. Bacteria were isolated from the liver, kidney and spleen of fish using 0.5% NaCl containing tryptic soy agar medium. Bacteria were grouped on the basis of their morphological characteristics. The colonies with clear zone on starch-ampicillin agar (SA agar) were tentatively identified as Aeromonas spp. Two hundred and twenty-six strains, about 70% of total isolates were assumed to be Aeromonas spp. Nine isolates were further identified based on the result of the API 20E test and PCR using primers specific for A. hydrophila 16S rRNA gene. The isolates were identified as A. hydrophila and the API 20E test showed differences in trisodium citrate, D-sucrose, D-melibiose, amygdalin and L-arabinose availability between the nine isolates and standard A. hydrophila. The susceptibilities of the isolated bacteria to 10 antibacterial agents were confirmed by the disk diffusion method. Isolated strains were found to be resistant to amoxicillin and ampicillin and sensitive to florfenicol. However, 7 isolates showed multiple drug resistances to erythromycin, oxytetracycline, nalidixic acid etc. Pathogenicity of the isolates was determined by the artificial challenge test on goldfish (Carassius auratus). Three isolates caused 60 ~ 80% mortality in goldfish within 5 days after the initiation of challenge. These results indicate that multiple drug resistant, highly pathogenic and exotic A. hydrophila can spread to domestic aquarium and the preventive treatment of fish before sale is necessary.