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Parrish K, Kirkland P, Horwood P, Chessman B, Ruming S, McGilvray G, Rose K, Hall J, Skerratt L. Delving into the Aftermath of a Disease-Associated Near-Extinction Event: A Five-Year Study of a Serpentovirus (Nidovirus) in a Critically Endangered Turtle Population. Viruses 2024; 16:653. [PMID: 38675993 PMCID: PMC11055124 DOI: 10.3390/v16040653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 04/17/2024] [Accepted: 04/20/2024] [Indexed: 04/28/2024] Open
Abstract
Bellinger River virus (BRV) is a serpentovirus (nidovirus) that was likely responsible for the catastrophic mortality of the Australian freshwater turtle Myuchelys georgesi in February 2015. From November 2015 to November 2020, swabs were collected from turtles during repeated river surveys to estimate the prevalence of BRV RNA, identify risk factors associated with BRV infection, and refine sample collection. BRV RNA prevalence at first capture was significantly higher in M. georgesi (10.8%) than in a coexisting turtle, Emydura macquarii (1.0%). For M. georgesi, various risk factors were identified depending on the analysis method, but a positive BRV result was consistently associated with a larger body size. All turtles were asymptomatic when sampled and conjunctival swabs were inferred to be optimal for ongoing monitoring. Although the absence of disease and recent BRV detections suggests a reduced ongoing threat, the potential for the virus to persist in an endemic focus or resurge in cyclical epidemics cannot be excluded. Therefore, BRV is an ongoing potential threat to the conservation of M. georgesi, and strict adherence to biosecurity principles is essential to minimise the risk of reintroduction or spread of BRV or other pathogens.
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Affiliation(s)
- Kate Parrish
- Virology Laboratory, Elizabeth Macarthur Agriculture Institute, Department of Primary Industries, Menangle, NSW 2568, Australia
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD 4810, Australia
| | - Peter Kirkland
- Virology Laboratory, Elizabeth Macarthur Agriculture Institute, Department of Primary Industries, Menangle, NSW 2568, Australia
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD 4810, Australia
| | - Paul Horwood
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD 4810, Australia
| | | | - Shane Ruming
- Biodiversity Conservation and Science, New South Wales Department of Climate Change, Energy, the Environment and Water, Coffs Harbour, NSW 2450, Australia
| | - Gerry McGilvray
- Biodiversity Conservation and Science, New South Wales Department of Climate Change, Energy, the Environment and Water, Coffs Harbour, NSW 2450, Australia
| | - Karrie Rose
- Australian Registry of Wildlife Health, Taronga Conservation Society Australia, Mosman, NSW 2088, Australia
| | - Jane Hall
- Australian Registry of Wildlife Health, Taronga Conservation Society Australia, Mosman, NSW 2088, Australia
| | - Lee Skerratt
- Melbourne Veterinary School, Faculty of Science, University of Melbourne, Werribee, VIC 3030, Australia
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Tillis SB, Ossiboff RJ, Wellehan JFX. Serpentoviruses Exhibit Diverse Organization and ORF Composition with Evidence of Recombination. Viruses 2024; 16:310. [PMID: 38400085 PMCID: PMC10892116 DOI: 10.3390/v16020310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 02/14/2024] [Accepted: 02/15/2024] [Indexed: 02/25/2024] Open
Abstract
Serpentoviruses are a subfamily of positive sense RNA viruses in the order Nidovirales, family Tobaniviridae, associated with respiratory disease in multiple clades of reptiles. While the broadest viral diversity is reported from captive pythons, other reptiles, including colubrid snakes, turtles, and lizards of captive and free-ranging origin are also known hosts. To better define serpentoviral diversity, eleven novel serpentovirus genomes were sequenced with an Illumina MiSeq and, when necessary, completed with other Sanger sequencing methods. The novel serpentoviral genomes, along with 57 other previously published serpentovirus genomes, were analyzed alongside four outgroup genomes. Genomic analyses included identifying unique genome templates for each serpentovirus clade, as well as analysis of coded protein composition, potential protein function, protein glycosylation sites, differences in phylogenetic history between open-reading frames, and recombination. Serpentoviral genomes contained diverse protein compositions. In addition to the fundamental structural spike, matrix, and nucleoprotein proteins required for virion formation, serpentovirus genomes also included 20 previously uncharacterized proteins. The uncharacterized proteins were homologous to a number of previously characterized proteins, including enzymes, transcription factors, scaffolding, viral resistance, and apoptosis-related proteins. Evidence for recombination was detected in multiple instances in genomes from both captive and free-ranging snakes. These results show serpentovirus as a diverse clade of viruses with genomes that code for a wide diversity of proteins potentially enhanced by recombination events.
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Affiliation(s)
- Steven B. Tillis
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL 32608, USA; (R.J.O.); (J.F.X.W.J.)
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Flies AS, Flies EJ, Fountain-Jones NM, Musgrove RE, Hamede RK, Philips A, Perrott MRF, Dunowska M. Wildlife nidoviruses: biology, epidemiology, and disease associations of selected nidoviruses of mammals and reptiles. mBio 2023; 14:e0071523. [PMID: 37439571 PMCID: PMC10470586 DOI: 10.1128/mbio.00715-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2023] Open
Abstract
Wildlife is the source of many emerging infectious diseases. Several viruses from the order Nidovirales have recently emerged in wildlife, sometimes with severe consequences for endangered species. The order Nidovirales is currently classified into eight suborders, three of which contain viruses of vertebrates. Vertebrate coronaviruses (suborder Cornidovirineae) have been extensively studied, yet the other major suborders have received less attention. The aim of this minireview was to summarize the key findings from the published literature on nidoviruses of vertebrate wildlife from two suborders: Arnidovirineae and Tornidovirineae. These viruses were identified either during investigations of disease outbreaks or through molecular surveys of wildlife viromes, and include pathogens of reptiles and mammals. The available data on key biological features, disease associations, and pathology are presented, in addition to data on the frequency of infections among various host populations, and putative routes of transmission. While nidoviruses discussed here appear to have a restricted in vivo host range, little is known about their natural life cycle. Observational field-based studies outside of the mortality events are needed to facilitate an understanding of the virus-host-environment interactions that lead to the outbreaks. Laboratory-based studies are needed to understand the pathogenesis of diseases caused by novel nidoviruses and their evolutionary histories. Barriers preventing research progress include limited funding and the unavailability of virus- and host-specific reagents. To reduce mortalities in wildlife and further population declines, proactive development of expertise, technologies, and networks should be developed. These steps would enable effective management of future outbreaks and support wildlife conservation.
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Affiliation(s)
- Andrew S. Flies
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia
| | - Emily J. Flies
- School of Natural Sciences, University of Tasmania, Hobart, Tasmania, Australia
- Healthy Landscapes Research Group, University of Tasmania, Hobart, Tasmania, Australia
| | | | - Ruth E. Musgrove
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia
| | - Rodrigo K. Hamede
- School of Natural Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | - Annie Philips
- Natural Resources and Environment Tasmania, Hobart, Tasmania, Australia
| | | | - Magdalena Dunowska
- School of Veterinary Science, Massey University, Palmerston North, New Zealand
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Tillis SB, Holt C, Havens S, Logan TD, Julander JG, Ossiboff RJ. In Vitro Characterization and Antiviral Susceptibility of Ophidian Serpentoviruses. Microorganisms 2023; 11:1371. [PMID: 37374873 DOI: 10.3390/microorganisms11061371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 05/09/2023] [Accepted: 05/20/2023] [Indexed: 06/29/2023] Open
Abstract
Ophidian serpentoviruses, positive-sense RNA viruses in the order Nidovirales, are important infectious agents of both captive and free-ranging reptiles. Although the clinical significance of these viruses can be variable, some serpentoviruses are pathogenic and potentially fatal in captive snakes. While serpentoviral diversity and disease potential are well documented, little is known about the fundamental properties of these viruses, including their potential host ranges, kinetics of growth, environmental stability, and susceptibility to common disinfectants and viricides. To address this, three serpentoviruses were isolated in culture from three unique PCR-positive python species: Ball python (Python regius), green tree python (Morelia viridis), and Stimson's python (Antaresia stimsoni). A median tissue culture infectious dose (TCID50) was established to characterize viral stability, growth, and susceptibility. All isolates showed an environmental stability of 10-12 days at room temperature (20 °C). While all three viruses produced variable peak titers on three different cell lines when incubated at 32 °C, none of the viruses detectably replicated at 35 °C. All viruses demonstrated a wide susceptibility to sanitizers, with 10% bleach, 2% chlorhexidine, and 70% ethanol inactivating the virus in one minute and 7% peroxide and a quaternary ammonium solution within three minutes. Of seven tested antiviral agents, remdesivir, ribavirin, and NITD-008, showed potent antiviral activity against the three viruses. Finally, the three isolates successfully infected 32 unique tissue culture cell lines representing different diverse reptile taxa and select mammals and birds as detected by epifluorescent immunostaining. This study represents the first characterization of in vitro properties of growth, stability, host range, and inactivation for a serpentovirus. The reported results provide the basis for procedures to mitigate the spread of serpentoviruses in captive snake colonies as well as identify potential non-pharmacologic and pharmacologic treatment options for ophidian serpentoviral infections.
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Affiliation(s)
- Steven B Tillis
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL 32608, USA
| | - Camille Holt
- Animal, Dairy, and Veterinary Sciences, College of Agriculture and Applied Sciences, Utah State University, Logan, UT 84322, USA
| | - Spencer Havens
- Animal, Dairy, and Veterinary Sciences, College of Agriculture and Applied Sciences, Utah State University, Logan, UT 84322, USA
| | - Tracey D Logan
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL 32608, USA
| | - Justin G Julander
- Animal, Dairy, and Veterinary Sciences, College of Agriculture and Applied Sciences, Utah State University, Logan, UT 84322, USA
| | - Robert J Ossiboff
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL 32608, USA
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Leineweber C, Marschang RE. Detection of nidoviruses in samples collected from captive snakes in Europe between 2016 and 2021. Vet Rec 2023; 192:e2588. [PMID: 36719283 DOI: 10.1002/vetr.2588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/14/2022] [Accepted: 12/23/2022] [Indexed: 02/01/2023]
Abstract
BACKGROUND Nidoviruses are increasingly detected in various snake species worldwide, but much remains to be learned about their distribution and the factors influencing their epidemiology. METHODS This retrospective study evaluated the results of routine nidovirus testing, by PCR, of 5210 swab samples from pet snakes from various European countries that were submitted to a commercial veterinary laboratory in Germany between 2016 and 2021. RESULTS The overall detection rate was 19.96%. However, the detection rate varied significantly depending on the snake species (p < 0.0001), with the highest rate in Indian pythons (Python molurus) (42.24%). Rates also varied depending on the season of sample collection (p < 0.0001), with the highest rate in winter (24.46%), and the country of sample origin (p < 0.0001), with the highest rate in Austria (36.69%). The detection rate also decreased significantly (p = 0.0003) over the 6-year observation period, from 26.43% to 17.64%. LIMITATION No information on clinical signs was available for most of the sampled snakes. CONCLUSION The present study supplies new information on the distribution of python nidoviruses (subgenus Roypretovirus) in pet snakes in Europe and indicates a dynamic situation with possible changes in prevalence over time.
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Guzy JC, Falk BG, Smith BJ, Willson JD, Reed RN, Aumen NG, Avery ML, Bartoszek IA, Campbell E, Cherkiss MS, Claunch NM, Currylow AF, Dean T, Dixon J, Engeman R, Funck S, Gibble R, Hengstebeck KC, Humphrey JS, Hunter ME, Josimovich JM, Ketterlin J, Kirkland M, Mazzotti FJ, McCleery R, Miller MA, McCollister M, Parker MR, Pittman SE, Rochford M, Romagosa C, Roybal A, Snow RW, Spencer MM, Waddle JH, Yackel Adams AA, Hart KM. Burmese pythons in Florida: A synthesis of biology, impacts, and management tools. NEOBIOTA 2023. [DOI: 10.3897/neobiota.80.90439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Burmese pythons (Python molurus bivittatus) are native to southeastern Asia, however, there is an established invasive population inhabiting much of southern Florida throughout the Greater Everglades Ecosystem. Pythons have severely impacted native species and ecosystems in Florida and represent one of the most intractable invasive-species management issues across the globe. The difficulty stems from a unique combination of inaccessible habitat and the cryptic and resilient nature of pythons that thrive in the subtropical environment of southern Florida, rendering them extremely challenging to detect. Here we provide a comprehensive review and synthesis of the science relevant to managing invasive Burmese pythons. We describe existing control tools and review challenges to productive research, identifying key knowledge gaps that would improve future research and decision making for python control.
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Tillis SB, Josimovich JM, Miller MA, Hoon-Hanks LL, Hartmann AM, Claunch NM, Iredale ME, Logan TD, Yackel Adams AA, Bartoszek IA, Humphrey JS, Kluever BM, Stenglein MD, Reed RN, Romagosa CM, Wellehan JFX, Ossiboff RJ. Divergent Serpentoviruses in Free-Ranging Invasive Pythons and Native Colubrids in Southern Florida, United States. Viruses 2022; 14:v14122726. [PMID: 36560729 PMCID: PMC9782103 DOI: 10.3390/v14122726] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/29/2022] [Accepted: 11/30/2022] [Indexed: 12/13/2022] Open
Abstract
Burmese python (Python bivittatus) is an invasive snake that has significantly affected ecosystems in southern Florida, United States. Aside from direct predation and competition, invasive species can also introduce nonnative pathogens that can adversely affect native species. The subfamily Serpentovirinae (order Nidovirales) is composed of positive-sense RNA viruses primarily found in reptiles. Some serpentoviruses, such as shingleback nidovirus, are associated with mortalities in wild populations, while others, including ball python nidovirus and green tree python nidovirus can be a major cause of disease and mortality in captive animals. To determine if serpentoviruses were present in invasive Burmese pythons in southern Florida, oral swabs were collected from both free-ranging and long-term captive snakes. Swabs were screened for the presence of serpentovirus by reverse transcription PCR and sequenced. A total serpentovirus prevalence of 27.8% was detected in 318 python samples. Of the initial swabs from 172 free-ranging pythons, 42 (24.4%) were positive for multiple divergent viral sequences comprising four clades across the sampling range. Both sex and snout-vent length were statistically significant factors in virus prevalence, with larger male snakes having the highest prevalence. Sampling location was statistically significant in circulating virus sequence. Mild clinical signs and lesions consistent with serpentovirus infection were observed in a subset of sampled pythons. Testing of native snakes (n = 219, 18 species) in part of the python range found no evidence of python virus spillover; however, five individual native snakes (2.3%) representing three species were PCR positive for unique, divergent serpentoviruses. Calculated pairwise uncorrected distance analysis indicated the newly discovered virus sequences likely represent three novel genera in the subfamily Serpentovirinae. This study is the first to characterize serpentovirus in wild free-ranging pythons or in any free-ranging North America reptile. Though the risk these viruses pose to the invasive and native species is unknown, the potential for spillover to native herpetofauna warrants further investigation.
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Affiliation(s)
- Steven B. Tillis
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL 32608, USA
| | - Jillian M. Josimovich
- U.S. Geological Survey, Fort Collins Science Center-South Florida Field Station in Everglades National Park, 40001 SR 9336, Homestead, FL 33034, USA
| | - Melissa A. Miller
- Florida Fish and Wildlife Conservation Commission, Davie, FL 33314, USA
| | - Laura L. Hoon-Hanks
- Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80521, USA
| | - Arik M. Hartmann
- Department of Biology, University of Florida, Gainesville, FL 32608, USA
| | - Natalie M. Claunch
- Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL 32608, USA
- School of Natural Resources and Environment, University of Florida, Gainesville, FL 32608, USA
| | - Marley E. Iredale
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL 32608, USA
| | - Tracey D. Logan
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL 32608, USA
| | - Amy A. Yackel Adams
- U.S. Geological Survey, Fort Collins Science Center, Fort Collins, CO 80526, USA
| | - Ian A. Bartoszek
- Conservancy of Southwest Florida, Environmental Science Department, Naples, FL 34102, USA
| | - John S. Humphrey
- U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center, Gainesville, FL 32641, USA
| | - Bryan M. Kluever
- U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, National Wildlife Research Center, Gainesville, FL 32641, USA
| | - Mark D. Stenglein
- Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80521, USA
| | - Robert N. Reed
- U.S. Geological Survey, Fort Collins Science Center, Fort Collins, CO 80526, USA
| | - Christina M. Romagosa
- Department of Wildlife Ecology and Conservation, University of Florida, Gainesville, FL 32608, USA
| | - James F. X. Wellehan
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL 32608, USA
| | - Robert J. Ossiboff
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL 32608, USA
- Correspondence:
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