Molecular epidemiology of Megalocytivirus in freshwater angelfish (Pterophyllum scalare) from Johor, Malaysia
Background and Aim: Malaysia has more than 630 culturists who are involved in the ornamental fish industry and culture 250 species, including local and exotic species. Among these viruses, megalocytiviruses have been associated with severe systemic diseases and economic losses in ornamental fish. Th...
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| Format: | Article |
| Language: | English |
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Veterinary World
2023-09-01
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| Series: | Veterinary World |
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| Online Access: | https://www.veterinaryworld.org/Vol.16/October-2023/19.pdf |
| _version_ | 1797653839518629888 |
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| author | Che Azarulzaman Che Johan Muhd Danish Daniel Abdullah Sharifah Noor Emilia Sandra Catherine Zainathan |
| author_facet | Che Azarulzaman Che Johan Muhd Danish Daniel Abdullah Sharifah Noor Emilia Sandra Catherine Zainathan |
| author_sort | Che Azarulzaman Che Johan |
| collection | DOAJ |
| description | Background and Aim: Malaysia has more than 630 culturists who are involved in the ornamental fish industry and culture 250 species, including local and exotic species. Among these viruses, megalocytiviruses have been associated with severe systemic diseases and economic losses in ornamental fish. The intensity of Megalocytivirus infection in Pterophyllum scalare in Malaysia remains unknown. Thus, this study aimed to investigate the occurrence of Megalocytivirus while discovering its associated risk factors and the genotypes of its causative agents in an ornamental fish farm in Malaysia.
Materials and Methods: Seven broodstock pairs of P. scalare were used in this study to follow the life stages of fish, from egg to market size. Water samples and other samples, such as mucus swabs, gill swabs, P. scalare eggs, fries, juveniles, snails, snail eggs, live feed (Tubifex worms and Moina spp.), sediment samples, and wild fish, were collected periodically for initial environmental sampling from day 0 to day 60. Nested polymerase chain reaction amplifications were performed for megalocytivirus-related sequences. The phylogenetic tree, including the sampled causative agents of megalocytiviruses, was inferred from the major capsid protein genes of all known Iridoviridae species. Pearson’s correlation coefficients were calculated to determine the strength of the correlation between the presence of megalocytiviruses in P. scalare samples and the associated risk factors.
Results: A total of 312 out of 935 pooled and individual samples tested positive for the presence of Megalocytivirus-related sequences, except snail eggs and wild fish (Poecilia reticulata). No clinical symptoms were observed in any fish samples. Megalocytivirus-associated viruses detected in water samples indicate horizontal transmission of the virus. All the nucleotide sequences found in this study had high nucleotide identities of 95%–99 % and were closely related to Megalocytivirus genotype I infectious spleen and kidney necrosis virus. Risk factors associated with Megalocytivirus include water temperature, dissolved oxygen (DO), pH, ammonia, nitrate, nitrite, and the life stages of P. scalare. High Megalocytivirus infection was detected when the water temperature, DO, and pH were high in P. scalare, high water temperature and nitrate in the water samples, and the same rate of Megalocytivirus infection in P. scalare fry and juveniles.
Conclusion: This is the first study to confirm the existence of different possible routes of megalocytivirus distribution in ornamental fish farms in Malaysia. Nevertheless, the connection between the mode of transmission and the risk factors for this virus needs to be explored further to recognize the evolution and potential new host species. |
| first_indexed | 2024-03-11T16:50:36Z |
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| language | English |
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| spelling | doaj.art-a37c9070327c4856b82cddedd1fcf95f2023-10-21T14:10:09ZengVeterinary WorldVeterinary World0972-89882231-09162023-09-0116102158217210.14202/vetworld.2023.2158-2172Molecular epidemiology of Megalocytivirus in freshwater angelfish (Pterophyllum scalare) from Johor, MalaysiaChe Azarulzaman Che Johan0https://orcid.org/0000-0002-2212-7833Muhd Danish Daniel Abdullah1https://orcid.org/0000-0001-9438-0128Sharifah Noor Emilia2https://orcid.org/0000-0002-9355-5085Sandra Catherine Zainathan3https://orcid.org/0000-0002-2138-2533Department of Aquaculture, Faculty of Fisheries and Food Science, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia.Department of Aquaculture, Faculty of Fisheries and Food Science, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia; Institute of Climate Adaptation and Marine Biotechnology, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia.Department of Aquaculture, Faculty of Fisheries and Food Science, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia.Department of Aquaculture, Faculty of Fisheries and Food Science, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia; Institute of Climate Adaptation and Marine Biotechnology, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia.Background and Aim: Malaysia has more than 630 culturists who are involved in the ornamental fish industry and culture 250 species, including local and exotic species. Among these viruses, megalocytiviruses have been associated with severe systemic diseases and economic losses in ornamental fish. The intensity of Megalocytivirus infection in Pterophyllum scalare in Malaysia remains unknown. Thus, this study aimed to investigate the occurrence of Megalocytivirus while discovering its associated risk factors and the genotypes of its causative agents in an ornamental fish farm in Malaysia. Materials and Methods: Seven broodstock pairs of P. scalare were used in this study to follow the life stages of fish, from egg to market size. Water samples and other samples, such as mucus swabs, gill swabs, P. scalare eggs, fries, juveniles, snails, snail eggs, live feed (Tubifex worms and Moina spp.), sediment samples, and wild fish, were collected periodically for initial environmental sampling from day 0 to day 60. Nested polymerase chain reaction amplifications were performed for megalocytivirus-related sequences. The phylogenetic tree, including the sampled causative agents of megalocytiviruses, was inferred from the major capsid protein genes of all known Iridoviridae species. Pearson’s correlation coefficients were calculated to determine the strength of the correlation between the presence of megalocytiviruses in P. scalare samples and the associated risk factors. Results: A total of 312 out of 935 pooled and individual samples tested positive for the presence of Megalocytivirus-related sequences, except snail eggs and wild fish (Poecilia reticulata). No clinical symptoms were observed in any fish samples. Megalocytivirus-associated viruses detected in water samples indicate horizontal transmission of the virus. All the nucleotide sequences found in this study had high nucleotide identities of 95%–99 % and were closely related to Megalocytivirus genotype I infectious spleen and kidney necrosis virus. Risk factors associated with Megalocytivirus include water temperature, dissolved oxygen (DO), pH, ammonia, nitrate, nitrite, and the life stages of P. scalare. High Megalocytivirus infection was detected when the water temperature, DO, and pH were high in P. scalare, high water temperature and nitrate in the water samples, and the same rate of Megalocytivirus infection in P. scalare fry and juveniles. Conclusion: This is the first study to confirm the existence of different possible routes of megalocytivirus distribution in ornamental fish farms in Malaysia. Nevertheless, the connection between the mode of transmission and the risk factors for this virus needs to be explored further to recognize the evolution and potential new host species.https://www.veterinaryworld.org/Vol.16/October-2023/19.pdfepidemiologygenotype iinfectious spleen and kidney necrosis virusmegalocytivirusornamental fishrisk factors |
| spellingShingle | Che Azarulzaman Che Johan Muhd Danish Daniel Abdullah Sharifah Noor Emilia Sandra Catherine Zainathan Molecular epidemiology of Megalocytivirus in freshwater angelfish (Pterophyllum scalare) from Johor, Malaysia Veterinary World epidemiology genotype i infectious spleen and kidney necrosis virus megalocytivirus ornamental fish risk factors |
| title | Molecular epidemiology of Megalocytivirus in freshwater angelfish (Pterophyllum scalare) from Johor, Malaysia |
| title_full | Molecular epidemiology of Megalocytivirus in freshwater angelfish (Pterophyllum scalare) from Johor, Malaysia |
| title_fullStr | Molecular epidemiology of Megalocytivirus in freshwater angelfish (Pterophyllum scalare) from Johor, Malaysia |
| title_full_unstemmed | Molecular epidemiology of Megalocytivirus in freshwater angelfish (Pterophyllum scalare) from Johor, Malaysia |
| title_short | Molecular epidemiology of Megalocytivirus in freshwater angelfish (Pterophyllum scalare) from Johor, Malaysia |
| title_sort | molecular epidemiology of megalocytivirus in freshwater angelfish pterophyllum scalare from johor malaysia |
| topic | epidemiology genotype i infectious spleen and kidney necrosis virus megalocytivirus ornamental fish risk factors |
| url | https://www.veterinaryworld.org/Vol.16/October-2023/19.pdf |
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