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Kim MJ, Baek EJ, Kim JO, Hwang JY, Kwon MG, Il Kim K. Application of iron flocculation to concentrate white spot syndrome virus in seawater. J Virol Methods 2022; 306:114554. [PMID: 35623490 DOI: 10.1016/j.jviromet.2022.114554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 05/15/2022] [Accepted: 05/22/2022] [Indexed: 10/18/2022]
Abstract
The iron flocculation method, which comprises the Fe-virus flocculate formation-filtration-resuspension steps, is extensively used to concentrate and precipitate viruses distributed in water. To apply this method to concentrate white spot syndrome virus (WSSV) in seawater, viral genomic and infective recovery yields were compared between polyethylene sulfone (PES) and polycarbonate (PC) membrane filters and two types of resuspension buffers (oxalate and ascorbate). Viral genome quantitation was determined above a 95% limit of detection (11.48 viral DNA copies/μL) using quantitative real-time PCR. From WSSV-spiked seawater (100 to 106 viral DNA copies/mL), the viral genomic recovery yields of the PES-Oxalate, PC-Oxalate, PES-Ascorbate, and PC-Ascorbate conditions were 78.67% ± 12.90%, 84.53% ± 24.30%, 85.59% ± 16.98%, and 93.74% ± 7.44%, respectively. The detectable Fe-virus flocculates collected by the PC membrane were approximately 101 WSSV DNA copies/mL of seawater, a value more than 10-fold higher than that compared to the PES membrane filter (102 WSSV DNA copies/mL), regardless of the resuspension buffer types. WSSV resuspended with oxalate buffer caused mass mortality among whiteleg shrimp (Litopenaeus vannamei), inducing the expression of the virus envelope protein, VP28, similar to that of a native virus, suggesting stable viral activity during the resuspension process. Based on the PES-Ascorbate, WSSV particles could be successfully concentrated in seawater from shrimp farms with white spot disease outbreaks (approximately 102 WSSV DNA copies/mL). Collectively, these findings indicate that the simple and efficient method of iron flocculation is sufficient to concentrate WSSV in seawater and could be used as a non-invasive approach and one of the reasonable diagnostic processes for white spot disease surveillance.
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Affiliation(s)
- Min Jae Kim
- Department of Aquatic Life Medicine, Pukyong National University, Busan, 48513, Republic of Korea
| | - Eun Jin Baek
- 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)
| | - Jee Youn Hwang
- Aquatic Disease Control Division, National Fishery Products Quality Management Service (NFQS)
| | - Mun-Gyeong Kwon
- Aquatic Disease Control Division, National Fishery Products Quality Management Service (NFQS)
| | - Kwang Il Kim
- Department of Aquatic Life Medicine, Pukyong National University, Busan, 48513, Republic of Korea.
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Mai TT, Kayansamruaj P, Soontara C, Kerddee P, Nguyen DH, Senapin S, Costa JZ, del-Pozo J, Thompson KD, Rodkhum C, Dong HT. Immunization of Nile Tilapia ( Oreochromis niloticus) Broodstock with Tilapia Lake Virus (TiLV) Inactivated Vaccines Elicits Protective Antibody and Passive Maternal Antibody Transfer. Vaccines (Basel) 2022; 10:167. [PMID: 35214626 PMCID: PMC8879158 DOI: 10.3390/vaccines10020167] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/17/2022] [Accepted: 01/19/2022] [Indexed: 02/06/2023] Open
Abstract
Tilapia lake virus (TiLV), a major pathogen of farmed tilapia, is known to be vertically transmitted. Here, we hypothesize that Nile tilapia (Oreochromis niloticus) broodstock immunized with a TiLV inactivated vaccine can mount a protective antibody response and passively transfer maternal antibodies to their fertilized eggs and larvae. To test this hypothesis, three groups of tilapia broodstock, each containing four males and eight females, were immunized with either a heat-killed TiLV vaccine (HKV), a formalin-killed TiLV vaccine (FKV) (both administered at 3.6 × 106 TCID50 per fish), or with L15 medium. Booster vaccination with the same vaccines was given 3 weeks later, and mating took place 1 week thereafter. Broodstock blood sera, fertilized eggs and larvae were collected from 6-14 weeks post-primary vaccination for measurement of TiLV-specific antibody (anti-TiLV IgM) levels. In parallel, passive immunization using sera from the immunized female broodstock was administered to naïve tilapia juveniles to assess if antibodies induced in immunized broodstock were protective. The results showed that anti-TiLV IgM was produced in the majority of both male and female broodstock vaccinated with either the HKV or FKV and that these antibodies could be detected in the fertilized eggs and larvae from vaccinated broodstock. Higher levels of maternal antibody were observed in fertilized eggs from broodstock vaccinated with HKV than those vaccinated with FKV. Low levels of TiLV-IgM were detected in some of the 1-3 day old larvae but were undetectable in 7-14 day old larvae from the vaccinated broodstock, indicating a short persistence of TiLV-IgM in larvae. Moreover, passive immunization proved that antibodies elicited by TiLV vaccination were able to confer 85% to 90% protection against TiLV challenge in naïve juvenile tilapia. In conclusion, immunization of tilapia broodstock with TiLV vaccines could be a potential strategy for the prevention of TiLV in tilapia fertilized eggs and larvae, with HKV appearing to be more promising than FKV for maternal vaccination.
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Affiliation(s)
- Thao Thu Mai
- Center of Excellence in Fish Infectious Diseases (CE FID), Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand; (T.T.M.); (D.-H.N.)
- The International Graduate Program of Veterinary Science and Technology (VST), Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand
- Division of Aquacultural Biotechnology, Biotechnology Center of Ho Chi Minh City, Ho Chi Minh 700000, Vietnam
| | - Pattanapon Kayansamruaj
- Center of Excellence in Aquatic Animal Health Management, Faculty of Fisheries, Kasetsart University, Bangkok 10900, Thailand; (P.K.); (C.S.); (P.K.)
| | - Chayanit Soontara
- Center of Excellence in Aquatic Animal Health Management, Faculty of Fisheries, Kasetsart University, Bangkok 10900, Thailand; (P.K.); (C.S.); (P.K.)
| | - Pattarawit Kerddee
- Center of Excellence in Aquatic Animal Health Management, Faculty of Fisheries, Kasetsart University, Bangkok 10900, Thailand; (P.K.); (C.S.); (P.K.)
| | - Dinh-Hung Nguyen
- Center of Excellence in Fish Infectious Diseases (CE FID), Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand; (T.T.M.); (D.-H.N.)
| | - Saengchan Senapin
- Fish Health Platform, Center of Excellence for Shrimp Molecular Biology and Biotechnology (Centex Shrimp), Faculty of Science, Mahidol University, Bangkok 10400, Thailand;
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Khlong Nueng 12120, Thailand
| | - Janina Z. Costa
- Aquaculture Research Group, Moredun Research Institute, Edinburgh EH26 0PZ, UK; (J.Z.C.); (K.D.T.)
| | - Jorge del-Pozo
- Infection and Immunity Division, Roslin Institute, Edinburgh EH25 9RG, UK;
| | - Kim D. Thompson
- Aquaculture Research Group, Moredun Research Institute, Edinburgh EH26 0PZ, UK; (J.Z.C.); (K.D.T.)
| | - Channarong Rodkhum
- Center of Excellence in Fish Infectious Diseases (CE FID), Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand; (T.T.M.); (D.-H.N.)
- The International Graduate Program of Veterinary Science and Technology (VST), Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Ha Thanh Dong
- Aquaculture and Aquatic Resources Program, Department of Food, Agriculture and Bioresources, School of Environment, Resources and Development, Asian Institute of Technology, Khlong Nueng 12120, Thailand
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Debnath PP, Dinh‐Hung N, Taengphu S, Nguyen VV, Delamare‐Deboutteville J, Senapin S, Vishnumurthy Mohan C, Dong HT, Rodkhum C. Tilapia Lake Virus was not detected in non-tilapine species within tilapia polyculture systems of Bangladesh. JOURNAL OF FISH DISEASES 2022; 45:77-87. [PMID: 34580880 PMCID: PMC9293328 DOI: 10.1111/jfd.13537] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 09/13/2021] [Accepted: 09/15/2021] [Indexed: 06/13/2023]
Abstract
Sixteen countries, including Bangladesh, have reported the presence of tilapia lake virus (TiLV), an emerging tilapia pathogen. Fish polyculture is a common farming practice in Bangladesh. Some unusual mortalities reported in species co-cultivated with TiLV-infected tilapia led us to investigate whether any of the co-cultivated species would also test positive for TiLV and whether they were susceptible to TiLV infection under controlled laboratory experiments. Using 183 samples obtained from 15 farms in six districts across Bangladesh, we determined that 20% of the farms tested positive for TiLV in tilapia, while 15 co-cultivated fish species and seven other invertebrates (e.g. insects and crustaceans) considered potential carriers all tested negative. Of the six representative fish species experimentally infected with TiLV, only Nile tilapia showed the typical clinical signs of the disease, with 70% mortality within 12 days. By contrast, four carp species and one catfish species challenged with TiLV showed no signs of TiLV infection. Challenged tilapia were confirmed as TiLV-positive by RT-qPCR, while challenged carp and walking catfish all tested negative. Overall, our field and laboratory findings indicate that species used in polycultures are not susceptible to TiLV. Although current evidence suggests that TiLV is likely host-specific to tilapia, targeted surveillance for TiLV in other fish species in polyculture systems should continue, in order to prepare for a possible future scenario where TiLV mutates and/or adapts to new host(s).
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Affiliation(s)
- Partho Pratim Debnath
- The International Graduate Course of Veterinary Science and Technology (VST)Faculty of Veterinary ScienceChulalongkorn UniversityBangkokThailand
- Department of Veterinary MicrobiologyCenter of Excellent in Fish Infectious Diseases (CE FID)Faculty of Veterinary ScienceChulalongkorn UniversityBangkokThailand
| | - Nguyen Dinh‐Hung
- Department of Veterinary MicrobiologyCenter of Excellent in Fish Infectious Diseases (CE FID)Faculty of Veterinary ScienceChulalongkorn UniversityBangkokThailand
| | - Suwimon Taengphu
- Fish Health PlatformCenter of Excellence for Shrimp Molecular Biology and Biotechnology (Centex Shrimp)Faculty of ScienceMahidol UniversityBangkokThailand
- National Center for Genetic Engineering and Biotechnology (BIOTEC)National Science and Technology Development Agency (NSTDA)Pathum ThaniThailand
| | | | | | - Saengchan Senapin
- Fish Health PlatformCenter of Excellence for Shrimp Molecular Biology and Biotechnology (Centex Shrimp)Faculty of ScienceMahidol UniversityBangkokThailand
- National Center for Genetic Engineering and Biotechnology (BIOTEC)National Science and Technology Development Agency (NSTDA)Pathum ThaniThailand
| | | | - Ha Thanh Dong
- Department of Food, Agriculture and BioresourcesAquaculture and Aquatic Resources Management ProgramAsian Institute of Technology (AIT)School of EnvironmentKlong LuangPathumthaniThailand
| | - Channarong Rodkhum
- The International Graduate Course of Veterinary Science and Technology (VST)Faculty of Veterinary ScienceChulalongkorn UniversityBangkokThailand
- Department of Veterinary MicrobiologyCenter of Excellent in Fish Infectious Diseases (CE FID)Faculty of Veterinary ScienceChulalongkorn UniversityBangkokThailand
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Mai TT, Kayansamruaj P, Taengphu S, Senapin S, Costa JZ, del‐Pozo J, Thompson KD, Rodkhum C, Dong HT. Efficacy of heat-killed and formalin-killed vaccines against Tilapia tilapinevirus in juvenile Nile tilapia (Oreochromis niloticus). JOURNAL OF FISH DISEASES 2021; 44:2097-2109. [PMID: 34477227 PMCID: PMC9291230 DOI: 10.1111/jfd.13523] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 08/03/2021] [Accepted: 08/03/2021] [Indexed: 06/02/2023]
Abstract
Tilapia tilapinevirus (also known as tilapia lake virus, TiLV) is considered to be a new threat to the global tilapia industry. The objective of this study was to develop simple cell culture-based heat-killed (HKV) and formalin-killed (FKV) vaccines for the prevention of disease caused by TiLV. The fish were immunized with 100 µl of either HKV or FKV by intraperitoneal injection with each vaccine containing 1.8 × 106 TCID50- inactivated virus. A booster vaccination was carried out at 21-day post-vaccination (dpv) using the same protocol. The fish were then challenged with a lethal dose of TiLV at 28 dpv. The expression of five immune genes (IgM, IgD, IgT, CD4 and CD8) in the head kidney and spleen of experimental fish was assessed at 14 and 21 dpv and again after the booster vaccination at 28 dpv. TiLV-specific IgM responses were measured by ELISA at the same time points. The results showed that both vaccines conferred significant protection, with relative percentage survival of 71.3% and 79.6% for HKV and FKV, respectively. Significant up-regulation of IgM and IgT was observed in the head kidney of fish vaccinated with HKV at 21 dpv, while IgM, IgD and CD4 expression increased in the head kidney of fish receiving FKV at the same time point. After booster vaccination, IgT and CD8 transcripts were significantly increased in the spleen of fish vaccinated with the HKV, but not with FKV. Both vaccines induced a specific IgM response in both serum and mucus. In summary, this study showed that both HKV and FKV are promising injectable vaccines for the prevention of disease caused by TiLV in Nile tilapia.
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Affiliation(s)
- Thao Thu Mai
- Center of Excellence in Fish Infectious Diseases (CE FID), Department of Veterinary MicrobiologyFaculty of Veterinary ScienceChulalongkorn UniversityBangkokThailand
- The International Graduate Program of Veterinary Science and Technology (VST)Faculty of Veterinary ScienceChulalongkorn UniversityBangkokThailand
- Division of Aquacultural BiotechnologyBiotechnology Center of Ho Chi Minh CityHo Chi MinhVietnam
| | - Pattanapon Kayansamruaj
- Center of Excellence in Aquatic Animal Health ManagementFaculty of FisheriesKasetsart UniversityBangkokThailand
| | - Suwimon Taengphu
- Fish Health PlatformCenter of Excellence for Shrimp Molecular Biology and Biotechnology (Centex Shrimp)Faculty of ScienceMahidol UniversityBangkokThailand
- National Center for Genetic Engineering and Biotechnology (BIOTEC)National Science and Technology Development Agency (NSTDA)Pathum ThaniThailand
| | - Saengchan Senapin
- Fish Health PlatformCenter of Excellence for Shrimp Molecular Biology and Biotechnology (Centex Shrimp)Faculty of ScienceMahidol UniversityBangkokThailand
- National Center for Genetic Engineering and Biotechnology (BIOTEC)National Science and Technology Development Agency (NSTDA)Pathum ThaniThailand
| | - Janina Z. Costa
- Aquaculture Research GroupMoredun Research InstituteEdinburghUK
| | - Jorge del‐Pozo
- Infection and Immunity DivisionRoslin InstituteEdinburghUK
| | - Kim D. Thompson
- Aquaculture Research GroupMoredun Research InstituteEdinburghUK
| | - Channarong Rodkhum
- Center of Excellence in Fish Infectious Diseases (CE FID), Department of Veterinary MicrobiologyFaculty of Veterinary ScienceChulalongkorn UniversityBangkokThailand
- The International Graduate Program of Veterinary Science and Technology (VST)Faculty of Veterinary ScienceChulalongkorn UniversityBangkokThailand
| | - Ha Thanh Dong
- Faculty of Science and TechnologySuan Sunandha Rajabhat UniversityBangkokThailand
- Department of Food, Agriculture and BioresourcesSchool of Environment, Resources and DevelopmentAsian Institute of TechnologyPathum ThaniThailand
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