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Cho YG, Kim JH, Choi HJ, Jang GI, Oh YK, Lee SJ, Hong SY, Kwon MG, Choi KS. First report of Perkinsus olseni infections in blood cockles Tegillarca granosa on the south coast of Korea. Dis Aquat Organ 2023; 156:39-45. [PMID: 38078797 DOI: 10.3354/dao03758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
The protozoan parasite Perkinsus olseni has become a focus of attention since it has been responsible for mass mortalities and economic losses in a wide range of bivalve hosts globally. The P. olseni host range along the south coast of Korea may extend beyond what was previously understood, and blood cockles in the Family Arcidae are also suggested to be potential hosts of P. olseni. In the present study, we applied histology and molecular techniques to identify Perkinsus sp. infections in the blood cockles Tegillarca granosa, which have been commercially exploited on the south coast of Korea for several decades. Histology and molecular techniques, including genus-specific immunofluorescence assay, species-specific fluorescence in situ hybridization, and phylogeny based on the ribosomal DNA internal transcribed spacer region revealed that T. granosa is infected by P. olseni, although the prevalence was low (0.5%). Histology revealed massive hemocyte infiltrations in the mantle, gill, and digestive gland connective tissues, indicating that the infection exerts negative impacts on the host cockles.
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Affiliation(s)
- Young-Ghan Cho
- Department of Marine Life Science (BK21 FOUR) and Marine Science Institute, Jeju National University, 102 Jejudaehakno, Jeju 63243, Republic of Korea
- Tidal Flat Research Center, National Institute of Fisheries and Science, Gunsan 54001, Republic of Korea
| | - Jeong-Hwa Kim
- Department of Marine Life Science (BK21 FOUR) and Marine Science Institute, Jeju National University, 102 Jejudaehakno, Jeju 63243, Republic of Korea
| | - Hee Jung Choi
- Aquatic Disease Control Division, National Fishery Products Quality Management Service, Busan 46083, Republic of Korea
| | - Gwang-Il Jang
- Aquatic Disease Control Division, National Fishery Products Quality Management Service, Busan 46083, Republic of Korea
| | - Yun-Kyeong Oh
- Aquatic Disease Control Division, National Fishery Products Quality Management Service, Busan 46083, Republic of Korea
| | - Soon-Jeong Lee
- Aquatic Disease Control Division, National Fishery Products Quality Management Service, Busan 46083, Republic of Korea
| | - Sung-Youl Hong
- Aquatic Disease Control Division, National Fishery Products Quality Management Service, Busan 46083, Republic of Korea
| | - Mun-Gyeong Kwon
- Aquatic Disease Control Division, National Fishery Products Quality Management Service, Busan 46083, Republic of Korea
| | - Kwang-Sik Choi
- Department of Marine Life Science (BK21 FOUR) and Marine Science Institute, Jeju National University, 102 Jejudaehakno, Jeju 63243, Republic of Korea
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Kim MJ, Kim JO, Jang GI, Kwon MG, Kim KI. Diagnostic validity of molecular diagnostic assays for white spot syndrome virus at different severity grades. Heliyon 2023; 9:e19351. [PMID: 37662749 PMCID: PMC10474407 DOI: 10.1016/j.heliyon.2023.e19351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 08/08/2023] [Accepted: 08/19/2023] [Indexed: 09/05/2023] Open
Abstract
The high virulence of the white spot syndrome virus (WSSV) in acute infections and the lack of effective treatments underscore the necessity for a rapid, accurate, and efficient diagnostic process to control white spot disease. The analytical sensitivity of diagnostic assays (polymerase chain reactions; PCRs and rapid diagnostic kit) at different severity grades of WSSV infection were determined using the 95% limit of detection (LOD95%). The LOD95% of nested, real-time, and one-step PCRs and rapid diagnostic kit were 0.70, 4.67, 1.19, and 79,434.65 viral genome copies/reactions, respectively. From the intramuscular challenge tests conducted under different dose and temperature conditions, the WSSV severity grades of time-course collected whiteleg shrimp (Litopenaeus vannamei) and dead or live shrimps were determined based on the viral loads of the pleopod. By applying the WSSV severity grades, a total of 92 shrimps were classified as G0. Furthermore, 92, 66, 199, and 79 shrimps were classified as G1, G2, G3, and G4, respectively. Additionally, 222 shrimps were classified as negative as WSSV was not confirmed in the nested PCR assay. Diagnostic sensitivity (DSe) and specificity (DSp) values of molecular diagnostic assays were compared with those of nested PCR in artificial WSSV-infected shrimp to evaluate diagnostic performance. The real-time and one-step PCRs exhibited a DSe >92.4% for G0 grade (approximately 101-102 copies/mg), indicating WSSV detection at low copy numbers. The rapid diagnostic kit presented a DSe >92.4% for G2 grade (approximately 104-105 copies/mg), suggesting the detection of WSSV-infected shrimp with clinical signs during the endemic period. These results suggest that the strategy of presumptive diagnosis using one-step PCR and rapid diagnostic kit at different seasonal periods followed by confirmatory diagnosis using real-time PCR assay could aid in controlling WSD with rapidity, accuracy, and cost-effectiveness.
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Affiliation(s)
- Min-Jae Kim
- Department of Aquatic Life Medicine, Pukyong National University, Busan, 48513, Republic of Korea
| | - Jae-Ok Kim
- Tongyeong Regional Office, National Fishery Products Quality Management Service (NFQS), Republic of Korea
| | - Gwang-Il Jang
- Aquatic Disease Control Division, National Fishery Products Quality Management Service (NFQS) , Republic of Korea
| | - Mun-Gyeong Kwon
- Aquatic Disease Control Division, National Fishery Products Quality Management Service (NFQS) , Republic of Korea
| | - Kwang-Il Kim
- Department of Aquatic Life Medicine, Pukyong National University, Busan, 48513, Republic of Korea
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Kim MJ, Kim JO, Jang GI, Kwon MG, Kim KI. Evaluation of the Horizontal Transmission of White Spot Syndrome Virus for Whiteleg Shrimp ( Litopenaeus vannamei) Based on the Disease Severity Grade and Viral Shedding Rate. Animals (Basel) 2023; 13:ani13101676. [PMID: 37238106 DOI: 10.3390/ani13101676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Revised: 05/13/2023] [Accepted: 05/16/2023] [Indexed: 05/28/2023] Open
Abstract
White spot syndrome virus (WSSV) is the most problematic pathogen in crustaceans. In this study, we investigated the horizontal transmission model of WSSV based on the correlation between the disease severity grade and viral shedding rate and determined the minimum infective dose of WSSV via the waterborne route. Intramuscular injection challenges at different doses and water temperatures revealed that the thresholds of viral shedding and mortality were G1 (3.1 × 103 copies/mg) and G2 (8.5 × 104 copies/mg), respectively. Furthermore, a positive linear correlation was observed between viral copies of pleopods and viral shedding rate (y = 0.7076x + 1.414; p < 0.001). Minimum infective doses of WSSV were determined via an immersion challenge. Infection was observed within 1, 3, and 7 d in 105-, 103-, and 101 copies/mL of seawater, respectively. In the cohabitation challenge, infection was observed within six days with viral loads of 101 to 102 copies/mL of seawater, which further increased in the recipient group. Our results indicate a positive correlation between disease severity grade and viral shedding rate of infected shrimp and suggest that the waterborne transmission of WSSV depends on the viral load and exposure period.
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Affiliation(s)
- Min-Jae Kim
- Department of Aquatic Life Medicine, Pukyong National University, Busan 48513, Republic of Korea
| | - Jae-Ok Kim
- Tongyeong Regional Office, National Fishery Products Quality Management Service (NFQS), Tongyeong 53019, Republic of Korea
| | - Gwang-Il Jang
- Aquatic Disease Control Division, National Fishery Products Quality Management Service (NFQS), Busan 49111, Republic of Korea
| | - Mun-Gyeong Kwon
- Aquatic Disease Control Division, National Fishery Products Quality Management Service (NFQS), Busan 49111, Republic of Korea
| | - Kwang-Il Kim
- Department of Aquatic Life Medicine, Pukyong National University, Busan 48513, Republic of Korea
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Jang GI, Kim SM, Oh YK, Lee SJ, Hong SY, Lee HE, Kwon MG, Kim BS. First Report of Enterocytozoon hepatopenaei Infection in Giant Freshwater Prawn ( Macrobrachium rosenbergii de Man) Cultured in the Republic of Korea. Animals (Basel) 2022; 12:ani12223149. [PMID: 36428377 PMCID: PMC9686700 DOI: 10.3390/ani12223149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 11/14/2022] [Accepted: 11/14/2022] [Indexed: 11/16/2022] Open
Abstract
In the Republic of Korea, Enterocytozoon hepatopenaei (EHP) was first isolated from Pacific whiteleg shrimp in April 2020; however, there are no existing reports of EHP infection in other shrimp or prawns. Here, we aimed to investigate EHP infection and its prevalence in giant freshwater prawn farms in the Republic of Korea. We tested prawns from 22 farms for EHP infection, and samples from eight farms showed positive EHP infection results in 2021. In EHP-infected prawn farms, the prevalence ranged from 4.9% to 18.2%. The prevalence of EHP infection in the Republic of Korea, derived from the prevalence in prawn farms, was estimated to be 0.8% in 2021. The proliferation of EHP was observed within the hepatopancreatic epithelial cells of prawns using H&E and Giemsa staining. Mature EHP was observed in the sinus between epithelial cells of the digestive tubules. Phylogenetic analysis revealed a clade distinct from the previously reported EHP in Pacific whiteleg shrimps. This is the first report of EHP infection in a giant freshwater prawn in the Republic of Korea, where the prevalence of EHP infection is not high, but it is recognized as an emerging disease that requires periodic monitoring and quarantine management in giant freshwater prawns.
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Affiliation(s)
- Gwang-Il Jang
- Aquatic Disease Control Division, National Fishery Products Quality Management Service, Busan 46083, Republic of Korea
| | - Su-Mi Kim
- Aquatic Disease Control Division, National Fishery Products Quality Management Service, Busan 46083, Republic of Korea
| | - Yun-Kyeong Oh
- Aquatic Disease Control Division, National Fishery Products Quality Management Service, Busan 46083, Republic of Korea
| | - Soon-Jeong Lee
- Aquatic Disease Control Division, National Fishery Products Quality Management Service, Busan 46083, Republic of Korea
| | - Sung-Youl Hong
- Aquatic Disease Control Division, National Fishery Products Quality Management Service, Busan 46083, Republic of Korea
| | - Hyo-Eun Lee
- Aquatic Disease Control Division, National Fishery Products Quality Management Service, Busan 46083, Republic of Korea
| | - Mun-Gyeong Kwon
- Aquatic Disease Control Division, National Fishery Products Quality Management Service, Busan 46083, Republic of Korea
| | - Bo-Seong Kim
- Department of Aquatic Life Medicine, College of Ocean Science and Technology, Kunsan National University, Gunsan 54150, Republic of Korea
- Correspondence: ; Tel.: +82-(0)63-469-1884
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Kim BS, Jang GI, Kim SM, Kim YS, Jeon YG, Oh YK, Hwang JY, Kwon MG. First Report of Enterocytozoon hepatopenaei Infection in Pacific Whiteleg Shrimp ( Litopenaeus vannamei) Cultured in Korea. Animals (Basel) 2021; 11:ani11113150. [PMID: 34827883 PMCID: PMC8614486 DOI: 10.3390/ani11113150] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 11/02/2021] [Accepted: 11/03/2021] [Indexed: 11/16/2022] Open
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.
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