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Koh EY, Ong J, Wang Y, Toh X, Fernandez CJ, Huangfu T, Hall RN, Toh S, Lim K, Sng W, Lim HP, Ho K, Chang SF, Yap HH. Rabbit haemorrhagic disease virus 2 from Singapore 2020 outbreak revealed an Australian recombinant variant. Virus Evol 2023; 9:vead029. [PMID: 37207001 PMCID: PMC10190043 DOI: 10.1093/ve/vead029] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Revised: 03/25/2023] [Accepted: 04/27/2023] [Indexed: 05/21/2023] Open
Abstract
Rabbit haemorrhagic disease (RHD) is a significant and debilitating viral disease affecting lagomorphs. In September 2020, Singapore reported its first cases of RHD virus (RHDV) infection in domesticated rabbits. The initial findings reported that the outbreak strain belonged to genotype GI.2 (RHDV2/RHDVb), and epidemiological investigations could not identify the definitive source of the virus origin. Further recombination detection and phylogenetic analyses of the Singapore outbreak strain revealed that the RHDV was a GI.2 structural (S)/GI.4 non-structural (NS) recombinant variant. Sequence analyses on the National Centre for Biotechnology Information (NCBI) database showed high homology to recently emerged Australian variants, which were prevalent in local Australian lagomorph populations since 2017. Time-structured and phylogeographic analyses for the S and NS genes revealed a close genetic relationship between the Singapore RHDV strain and the Australian RHDV variants. More thorough epidemiological inquiries are necessary to ascertain how an Australian RHDV was introduced into the Singapore rabbit population, and opportune development of RHDV diagnostics and vaccines will be important to safeguard lagomorphs from future RHDV infection and disease management.
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Affiliation(s)
| | - Jasmine Ong
- Centre for Animal & Veterinary Sciences, Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), 1 Cluny Road, Singapore Botanic Gardens 259569, Singapore
| | - Yifan Wang
- Centre for Animal & Veterinary Sciences, Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), 1 Cluny Road, Singapore Botanic Gardens 259569, Singapore
| | - Xinyu Toh
- Centre for Animal & Veterinary Sciences, Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), 1 Cluny Road, Singapore Botanic Gardens 259569, Singapore
| | - Charlene Judith Fernandez
- Centre for Animal & Veterinary Sciences, Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), 1 Cluny Road, Singapore Botanic Gardens 259569, Singapore
| | - Taoqi Huangfu
- Centre for Animal & Veterinary Sciences, Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), 1 Cluny Road, Singapore Botanic Gardens 259569, Singapore
| | | | - Steffie Toh
- Centre for Animal & Veterinary Sciences, Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), 1 Cluny Road, Singapore Botanic Gardens 259569, Singapore
| | - Kelvin Lim
- Veterinary Health Management, Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), 1 Cluny Road, Singapore Botanic Gardens 259569, Singapore
| | - Wendy Sng
- Veterinary Health Management, Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), 1 Cluny Road, Singapore Botanic Gardens 259569, Singapore
| | - Hwee Ping Lim
- Veterinary Health Management, Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), 1 Cluny Road, Singapore Botanic Gardens 259569, Singapore
| | - Kelvin Ho
- Veterinary Health Management, Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), 1 Cluny Road, Singapore Botanic Gardens 259569, Singapore
| | - Siow Foong Chang
- Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), 1 Cluny Road, Singapore Botanic Gardens 259569, Singapore
| | - Him Hoo Yap
- Animal and Veterinary Service, National Parks Board (NParks), 1 Cluny Road, Singapore Botanic Gardens 259569, Singapore
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Lim K, Tan A, Ho K, Sng W, Lim HP, Chan C, Toh X, Ong J, Chang SF, Fernandez CJ. Resolution of rabbit haemorrhagic disease virus 2 (RHDV2; Lagovirus europeus GI.2) outbreak in Singapore. Transbound Emerg Dis 2021; 69:3077-3083. [PMID: 34480780 DOI: 10.1111/tbed.14312] [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: 06/14/2021] [Revised: 08/30/2021] [Accepted: 09/02/2021] [Indexed: 11/29/2022]
Abstract
Rabbit haemorrhagic disease (RHD) is a highly contagious viral disease affecting lagomorphs. The first documented cases of RHD in Singapore occurred in adult pet European rabbits in September 2020. Singapore subsequently declared the outbreak resolved in December 2020. Epidemiological investigations ruled out introductions via importation of infected rabbits and contaminated feed. The source could not be definitively determined. However, the findings suggested that the incident involved both inter- and intra-household transmission and veterinary clinic-household transmission. This incident demonstrated the importance of sustained application of biosecurity measures, epidemiological investigations including active case finding, control measures such as expedient vaccine dissemination and risk communications. It showed that even without a wild lagomorph population, an urbanized city-state like Singapore could still encounter emerging diseases such as RHD. Given its social impact on rabbit owners, the National Parks Board, Singapore and private veterinarians worked together to communicate with rabbit owners in order to urge them to adopt biosecurity measures and to address their concerns.
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Affiliation(s)
- Kelvin Lim
- Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), Botanic Gardens, Singapore, Singapore
| | - Alwyn Tan
- Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), Botanic Gardens, Singapore, Singapore
| | - Kelvin Ho
- Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), Botanic Gardens, Singapore, Singapore
| | - Wendy Sng
- Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), Botanic Gardens, Singapore, Singapore
| | - Hwee Ping Lim
- Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), Botanic Gardens, Singapore, Singapore
| | - Cathy Chan
- The Animal Doctors Pte Ltd (Singapore), Singapore, Singapore
| | - Xinyu Toh
- Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), Botanic Gardens, Singapore, Singapore
| | - Jasmine Ong
- Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), Botanic Gardens, Singapore, Singapore
| | - Siow Foong Chang
- Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), Botanic Gardens, Singapore, Singapore
| | - Charlene Judith Fernandez
- Professional and Scientific Services, Animal and Veterinary Service, National Parks Board (NParks), Botanic Gardens, Singapore, Singapore
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