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Slape RL, Milic NL. Exploring the most common lesion of Australian farmed saltwater crocodile (Crocodylus porosus) belly skin in the Northern Territory. Vet J 2024; 306:106174. [PMID: 38879075 DOI: 10.1016/j.tvjl.2024.106174] [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: 02/01/2024] [Revised: 06/10/2024] [Accepted: 06/12/2024] [Indexed: 06/20/2024]
Abstract
This is the first descriptive study to characterise and identify the most common lesions on harvested Australian saltwater crocodiles (Crocodylus porosus). 88 skins were examined over a 17-month period as part of normal farming practices, 2901 lesions identified, with scale location, location of the lesion on the scale, and characteristics (contour, keratin normality, translucency and colour) recorded. The study determined that linear lesions accounted for 68.25 % of lesions followed by foci lesions 17.24 %. Lesions were distributed on the upper proportion of the belly skin (77.8 %) and along the midline (72 %). The most common lesion identified was a single translucent linear lesion across the scale that otherwise appeared normal (58.95 %). While there is extensive research into pathogenic agents, further research is recommended to explore further causation of linear lesions, and factors that may contribute to their prevention. Given the subjective nature of crocodile skin grading, it is recommended future research into lesions is required to ensure the sustainability and profitability of the industry.
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Affiliation(s)
- Rhiannon L Slape
- Faculty of Health, Charles Darwin University, Darwin, Northern Territory 0909, Australia.
| | - Natalie L Milic
- Faculty of Health, Charles Darwin University, Darwin, Northern Territory 0909, Australia
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2
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Habarugira G, Harrison JJ, Moran J, Suen WW, Colmant AMG, Hobson-Peters J, Isberg SR, Bielefeldt-Ohmann H, Hall RA. A chimeric vaccine protects farmed saltwater crocodiles from West Nile virus-induced skin lesions. NPJ Vaccines 2023; 8:93. [PMID: 37369653 DOI: 10.1038/s41541-023-00688-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 05/30/2023] [Indexed: 06/29/2023] Open
Abstract
West Nile virus (WNV) causes skin lesions in farmed crocodiles leading to the depreciation of the value of their hides and significant economic losses. However, there is no commercially available vaccine designed for use in crocodilians against WNV. We tested chimeric virus vaccines composed of the non-structural genes of the insect-specific flavivirus Binjari virus (BinJV) and genes encoding the structural proteins of WNV. The BinJV/WNV chimera, is antigenically similar to wild-type WNV but replication-defective in vertebrates. Intramuscular injection of two doses of BinJV/WNV in hatchling saltwater crocodiles (Crocodylus porosus) elicited a robust neutralising antibody response and conferred protection against viremia and skin lesions after challenge with WNV. In contrast, mock-vaccinated crocodiles became viraemic and 22.2% exhibited WNV-induced lesions. This suggests that the BinJV/WNV chimera is a safe and efficacious vaccine for preventing WNV-induced skin lesions in farmed crocodilians.
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Affiliation(s)
- Gervais Habarugira
- School of Veterinary Science, The University of Queensland, Gatton, QLD, Australia
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Australia
| | - Jessica J Harrison
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Australia
| | - Jasmin Moran
- Centre for Crocodile Research, Noonamah, NT, Australia
| | - Willy W Suen
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Australia
- Australian Centre for Disease Preparedness, The Commonwealth Scientific and Industrial Research Organisation, Geelong, VIC, 3219, Australia
| | - Agathe M G Colmant
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, St Lucia, QLD, Australia
- Unité des Virus Émergents (UVE) Aix-Marseille Univ-IRD 190-Inserm 1207, Marseille, France
| | - Jody Hobson-Peters
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Australia
- Australian Infectious Diseases Research Centre, The University of Queensland, St Lucia, QLD, Australia
| | | | - Helle Bielefeldt-Ohmann
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Australia.
- Australian Infectious Diseases Research Centre, The University of Queensland, St Lucia, QLD, Australia.
| | - Roy A Hall
- School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Australia.
- Australian Infectious Diseases Research Centre, The University of Queensland, St Lucia, QLD, Australia.
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Arthropod-Borne Virus Surveillance as a Tool to Study the Australian Mosquito Virome. Viruses 2022; 14:v14091882. [PMID: 36146689 PMCID: PMC9502171 DOI: 10.3390/v14091882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 08/23/2022] [Accepted: 08/24/2022] [Indexed: 12/05/2022] Open
Abstract
Mosquitoes (n = 4381 in 198 pools) were collected in March and April 2018 to survey the presence of West Nile virus Kunjin strain in mosquito populations around crocodile farms in the Darwin region of the Northern Territory (NT) of Australia. While no Kunjin virus was detected in these mosquitoes, we applied our viral replicative intermediates screening system termed monoclonal antibodies to viral RNA intermediates in cells or MAVRIC to this set of samples. This resulted in the detection of 28 pools with virus replicating in C6/36 mosquito cells and the identification of three insect viruses from three distinct virus classes. We demonstrate the persistence of the insect-specific flavivirus Palm Creek virus in Coquillettidia xanthogaster mosquitoes from Darwin over almost a decade, with limited genetic drift. We also detected a novel Hubei macula-like virus 3 strain in samples from two mosquito genera, suggesting the virus, for which the sequence was originally detected in spiders and soybean thrips, might be involved in a horizontal transmission cycle between arthropods and plants. Overall, these data demonstrate the strength of the optimized MAVRIC system and contribute to our general knowledge of the mosquito virome and insect viruses.
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Kurucz N, McMahon JL, Warchot A, Hewitson G, Barcelon J, Moore F, Moran J, Harrison JJ, Colmant AMG, Staunton KM, Ritchie SA, Townsend M, Steiger DM, Hall RA, Isberg SR, Hall-Mendelin S. Nucleic Acid Preservation Card Surveillance Is Effective for Monitoring Arbovirus Transmission on Crocodile Farms and Provides a One Health Benefit to Northern Australia. Viruses 2022; 14:v14061342. [PMID: 35746812 PMCID: PMC9227548 DOI: 10.3390/v14061342] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 06/09/2022] [Accepted: 06/09/2022] [Indexed: 01/15/2023] Open
Abstract
The Kunjin strain of West Nile virus (WNVKUN) is a mosquito-transmitted flavivirus that can infect farmed saltwater crocodiles in Australia and cause skin lesions that devalue the hides of harvested animals. We implemented a surveillance system using honey-baited nucleic acid preservation cards to monitor WNVKUN and another endemic flavivirus pathogen, Murray Valley encephalitis virus (MVEV), on crocodile farms in northern Australia. The traps were set between February 2018 and July 2020 on three crocodile farms in Darwin (Northern Territory) and one in Cairns (North Queensland) at fortnightly intervals with reduced trapping during the winter months. WNVKUN RNA was detected on all three crocodile farms near Darwin, predominantly between March and May of each year. Two of the NT crocodile farms also yielded the detection of MVE viral RNA sporadically spread between April and November in 2018 and 2020. In contrast, no viral RNA was detected on crocodile farms in Cairns during the entire trapping period. The detection of WNVKUN and MVEV transmission by FTATM cards on farms in the Northern Territory generally correlated with the detection of their transmission to sentinel chicken flocks in nearby localities around Darwin as part of a separate public health surveillance program. While no isolates of WNVKUN or MVEV were obtained from mosquitoes collected on Darwin crocodile farms immediately following the FTATM card detections, we did isolate another flavivirus, Kokobera virus (KOKV), from Culex annulirostris mosquitoes. Our studies support the use of the FTATM card system as a sensitive and accurate method to monitor the transmission of WNVKUN and other arboviruses on crocodile farms to enable the timely implementation of mosquito control measures. Our detection of MVEV transmission and isolation of KOKV from mosquitoes also warrants further investigation of their potential role in causing diseases in crocodiles and highlights a “One Health” issue concerning arbovirus transmission to crocodile farm workers. In this context, the introduction of FTATM cards onto crocodile farms appears to provide an additional surveillance tool to detect arbovirus transmission in the Darwin region, allowing for a more timely intervention of vector control by relevant authorities.
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Affiliation(s)
- Nina Kurucz
- Medical Entomology, Centre for Disease Control, Public Health Unit, NT Health, Darwin, NT 0811, Australia; (N.K.); (A.W.)
| | - Jamie Lee McMahon
- Public Health Virology, Forensic and Scientific Services, Queensland Health, Coopers Plains, QLD 4108, Australia; (J.L.M.); (G.H.); (J.B.); (F.M.)
| | - Allan Warchot
- Medical Entomology, Centre for Disease Control, Public Health Unit, NT Health, Darwin, NT 0811, Australia; (N.K.); (A.W.)
| | - Glen Hewitson
- Public Health Virology, Forensic and Scientific Services, Queensland Health, Coopers Plains, QLD 4108, Australia; (J.L.M.); (G.H.); (J.B.); (F.M.)
| | - Jean Barcelon
- Public Health Virology, Forensic and Scientific Services, Queensland Health, Coopers Plains, QLD 4108, Australia; (J.L.M.); (G.H.); (J.B.); (F.M.)
| | - Frederick Moore
- Public Health Virology, Forensic and Scientific Services, Queensland Health, Coopers Plains, QLD 4108, Australia; (J.L.M.); (G.H.); (J.B.); (F.M.)
| | - Jasmin Moran
- Centre for Crocodile Research, Noonamah, NT 0837, Australia;
| | - Jessica J. Harrison
- School of Chemistry and Molecular Biosciences, University of Queensland, St. Lucia, QLD 4072, Australia; (J.J.H.); (A.M.G.C.); (R.A.H.)
| | - Agathe M. G. Colmant
- School of Chemistry and Molecular Biosciences, University of Queensland, St. Lucia, QLD 4072, Australia; (J.J.H.); (A.M.G.C.); (R.A.H.)
| | - Kyran M. Staunton
- Australian Institute of Tropical Health and Medicine, James Cook University, Smithfield, QLD 4878, Australia; (K.M.S.); (S.A.R.); (M.T.); (D.M.S.)
| | - Scott A. Ritchie
- Australian Institute of Tropical Health and Medicine, James Cook University, Smithfield, QLD 4878, Australia; (K.M.S.); (S.A.R.); (M.T.); (D.M.S.)
| | - Michael Townsend
- Australian Institute of Tropical Health and Medicine, James Cook University, Smithfield, QLD 4878, Australia; (K.M.S.); (S.A.R.); (M.T.); (D.M.S.)
| | - Dagmar Meyer Steiger
- Australian Institute of Tropical Health and Medicine, James Cook University, Smithfield, QLD 4878, Australia; (K.M.S.); (S.A.R.); (M.T.); (D.M.S.)
| | - Roy A. Hall
- School of Chemistry and Molecular Biosciences, University of Queensland, St. Lucia, QLD 4072, Australia; (J.J.H.); (A.M.G.C.); (R.A.H.)
- Australian Infectious Diseases Centre, University of Queensland, St. Lucia, QLD 4072, Australia
| | - Sally R. Isberg
- Centre for Crocodile Research, Noonamah, NT 0837, Australia;
- Correspondence: (S.R.I.); (S.H.-M.)
| | - Sonja Hall-Mendelin
- Public Health Virology, Forensic and Scientific Services, Queensland Health, Coopers Plains, QLD 4108, Australia; (J.L.M.); (G.H.); (J.B.); (F.M.)
- Correspondence: (S.R.I.); (S.H.-M.)
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Habarugira G, Moran J, Harrison JJ, Isberg SR, Hobson-Peters J, Hall RA, Bielefeldt-Ohmann H. Evidence of Infection with Zoonotic Mosquito-Borne Flaviviruses in Saltwater Crocodiles (Crocodylus porosus) in Northern Australia. Viruses 2022; 14:v14051106. [PMID: 35632847 PMCID: PMC9144604 DOI: 10.3390/v14051106] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 05/18/2022] [Accepted: 05/19/2022] [Indexed: 11/16/2022] Open
Abstract
The risk of flavivirus infections among the crocodilian species was not recognised until West Nile virus (WNV) was introduced into the Americas. The first outbreaks caused death and substantial economic losses in the alligator farming industry. Several other WNV disease episodes have been reported in crocodilians in other parts of the world, including Australia and Africa. Considering that WNV shares vectors with other flaviviruses, crocodilians are highly likely to also be exposed to flaviviruses other than WNV. A serological survey for flaviviral infections was conducted on saltwater crocodiles (Crocodylus porosus) at farms in the Northern Territory, Australia. Five hundred serum samples, collected from three crocodile farms, were screened using a pan-flavivirus-specific blocking ELISA. The screening revealed that 26% (n = 130/500) of the animals had antibodies to flaviviruses. Of these, 31.5% had neutralising antibodies to WNVKUN (Kunjin strain), while 1.5% had neutralising antibodies to another important flavivirus pathogen, Murray Valley encephalitis virus (MVEV). Of the other flaviviruses tested for, Fitzroy River virus (FRV) was the most frequent (58.5%) in which virus neutralising antibodies were detected. Our data indicate that farmed crocodiles in the Northern Territory are exposed to a range of potentially zoonotic flaviviruses, in addition to WNVKUN. While these flaviviruses do not cause any known diseases in crocodiles, there is a need to investigate whether infected saltwater crocodiles can develop a viremia to sustain the transmission cycle or farmed crocodilians can be used as sentinels to monitor the dynamics of arboviral infections in tropical areas.
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Affiliation(s)
- Gervais Habarugira
- School of Veterinary Science, The University of Queensland, Gatton, QLD 4343, Australia;
| | - Jasmin Moran
- Centre for Crocodile Research, Noonamah, NT 0837, Australia; (J.M.); (S.R.I.)
| | - Jessica J. Harrison
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD 4072, Australia; (J.J.H.); (J.H.-P.); (R.A.H.)
- Australian Infectious Diseases Research Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Sally R. Isberg
- Centre for Crocodile Research, Noonamah, NT 0837, Australia; (J.M.); (S.R.I.)
| | - Jody Hobson-Peters
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD 4072, Australia; (J.J.H.); (J.H.-P.); (R.A.H.)
- Australian Infectious Diseases Research Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Roy A. Hall
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD 4072, Australia; (J.J.H.); (J.H.-P.); (R.A.H.)
- Australian Infectious Diseases Research Centre, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Helle Bielefeldt-Ohmann
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, QLD 4072, Australia; (J.J.H.); (J.H.-P.); (R.A.H.)
- Australian Infectious Diseases Research Centre, The University of Queensland, St Lucia, QLD 4072, Australia
- Correspondence:
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Byas AD, Gallichotte EN, Hartwig AE, Porter SM, Gordy PW, Felix TA, Bowen RA, Ebel GD, Bosco-Lauth AM. American alligators are capable of West Nile virus amplification, mosquito infection and transmission. Virology 2022; 568:49-55. [PMID: 35114499 PMCID: PMC8866202 DOI: 10.1016/j.virol.2022.01.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 01/17/2022] [Accepted: 01/19/2022] [Indexed: 10/19/2022]
Abstract
West Nile virus (WNV) overwintering is poorly understood and likely multifactorial. Interest in alligators as a potential amplifying host arose when it was shown that they develop viremias theoretically sufficient to infect mosquitoes. We examined potential ways in which alligators may contribute to the natural ecology of WNV. We experimentally demonstrated that alligators are capable of WNV amplification with subsequent mosquito infection and transmission capability, that WNV-infected mosquitoes readily infect alligators and that water can serve as a source of infection for alligators but does not easily serve as in intermediate means for transmission between birds and alligators. These findings indicate potential mechanisms for maintenance of WNV outside of the primary bird-mosquito transmission cycle.
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Affiliation(s)
- Alex D. Byas
- Colorado State University, Microbiology, Immunology & Pathology Department, Fort Collins, CO, USA
| | - Emily N. Gallichotte
- Colorado State University, Microbiology, Immunology & Pathology Department, Fort Collins, CO, USA
| | - Airn E. Hartwig
- Colorado State University, Biomedical Sciences Department, Fort Collins, CO, USA
| | - Stephanie M. Porter
- Colorado State University, Microbiology, Immunology & Pathology Department, Fort Collins, CO, USA
| | - Paul W. Gordy
- Colorado State University, Biomedical Sciences Department, Fort Collins, CO, USA
| | - Todd A. Felix
- United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, Lakewood, CO, USA
| | - Richard A. Bowen
- Colorado State University, Biomedical Sciences Department, Fort Collins, CO, USA
| | - Gregory D. Ebel
- Colorado State University, Microbiology, Immunology & Pathology Department, Fort Collins, CO, USA
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West Nile Virus: An Update on Pathobiology, Epidemiology, Diagnostics, Control and "One Health" Implications. Pathogens 2020; 9:pathogens9070589. [PMID: 32707644 PMCID: PMC7400489 DOI: 10.3390/pathogens9070589] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 07/16/2020] [Accepted: 07/16/2020] [Indexed: 02/06/2023] Open
Abstract
West Nile virus (WNV) is an important zoonotic flavivirus responsible for mild fever to severe, lethal neuroinvasive disease in humans, horses, birds, and other wildlife species. Since its discovery, WNV has caused multiple human and animal disease outbreaks in all continents, except Antarctica. Infections are associated with economic losses, mainly due to the cost of treatment of infected patients, control programmes, and loss of animals and animal products. The pathogenesis of WNV has been extensively investigated in natural hosts as well as in several animal models, including rodents, lagomorphs, birds, and reptiles. However, most of the proposed pathogenesis hypotheses remain contentious, and much remains to be elucidated. At the same time, the unavailability of specific antiviral treatment or effective and safe vaccines contribute to the perpetuation of the disease and regular occurrence of outbreaks in both endemic and non-endemic areas. Moreover, globalisation and climate change are also important drivers of the emergence and re-emergence of the virus and disease. Here, we give an update of the pathobiology, epidemiology, diagnostics, control, and “One Health” implications of WNV infection and disease.
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Habarugira G, Moran J, Colmant AM, Davis SS, O’Brien CA, Hall-Mendelin S, McMahon J, Hewitson G, Nair N, Barcelon J, Suen WW, Melville L, Hobson-Peters J, Hall RA, Isberg SR, Bielefeldt-Ohmann H. Mosquito-Independent Transmission of West Nile virus in Farmed Saltwater Crocodiles ( Crocodylus porosus). Viruses 2020; 12:v12020198. [PMID: 32054016 PMCID: PMC7077242 DOI: 10.3390/v12020198] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 02/10/2020] [Indexed: 12/15/2022] Open
Abstract
West Nile virus, Kunjin strain (WNVKUN) is endemic in Northern Australia, but rarely causes clinical disease in humans and horses. Recently, WNVKUN genomic material was detected in cutaneous lesions of farmed saltwater crocodiles (Crocodylus porosus), but live virus could not be isolated, begging the question of the pathogenesis of these lesions. Crocodile hatchlings were experimentally infected with either 105 (n = 10) or 104 (n = 11) TCID50-doses of WNVKUN and each group co-housed with six uninfected hatchlings in a mosquito-free facility. Seven hatchlings were mock-infected and housed separately. Each crocodile was rotationally examined and blood-sampled every third day over a 3-week period. Eleven animals, including three crocodiles developing typical skin lesions, were culled and sampled 21 days post-infection (dpi). The remaining hatchlings were blood-sampled fortnightly until experimental endpoint 87 dpi. All hatchlings remained free of overt clinical disease, apart from skin lesions, throughout the experiment. Viremia was detected by qRT-PCR in infected animals during 2–17 dpi and in-contact animals 11–21 dpi, indicating horizontal mosquito-independent transmission. Detection of viral genome in tank-water as well as oral and cloacal swabs, collected on multiple days, suggests that shedding into pen-water and subsequent mucosal infection is the most likely route. All inoculated animals and some in-contact animals developed virus-neutralizing antibodies detectable from 17 dpi. Virus-neutralizing antibody titers continued to increase in exposed animals until the experimental endpoint, suggestive of persisting viral antigen. However, no viral antigen was detected by immunohistochemistry in any tissue sample, including from skin and intestine. While this study confirmed that infection of saltwater crocodiles with WNVKUN was associated with the formation of skin lesions, we were unable to elucidate the pathogenesis of these lesions or the nidus of viral persistence. Our results nevertheless suggest that prevention of WNVKUN infection and induction of skin lesions in farmed crocodiles may require management of both mosquito-borne and water-borne viral transmission in addition to vaccination strategies.
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Affiliation(s)
- Gervais Habarugira
- School of Veterinary Science, University of Queensland, Gatton, Qld 4343, Australia;
| | - Jasmin Moran
- Centre for Crocodile Research, Noonamah, NT 0837, Australia;
| | - Agathe M.G. Colmant
- School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, Qld 4072, Australia (C.A.O.); (W.W.S.); (J.H.-P.)
- Australian Infectious Diseases Centre, University of Queensland, St Lucia, Qld 4072, Australia
| | - Steven S. Davis
- Berrimah Veterinary Laboratories, NT 0828, Australia; (S.S.D.); (L.M.)
| | - Caitlin A. O’Brien
- School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, Qld 4072, Australia (C.A.O.); (W.W.S.); (J.H.-P.)
- Australian Infectious Diseases Centre, University of Queensland, St Lucia, Qld 4072, Australia
| | - Sonja Hall-Mendelin
- Queensland Health, Forensic and Scientific Services, Public Health Virology, Coopers Plains, Qld 4108, Australia; (S.H.-M.); (J.M.); (G.H.); (N.N.); (J.B.)
| | - Jamie McMahon
- Queensland Health, Forensic and Scientific Services, Public Health Virology, Coopers Plains, Qld 4108, Australia; (S.H.-M.); (J.M.); (G.H.); (N.N.); (J.B.)
| | - Glen Hewitson
- Queensland Health, Forensic and Scientific Services, Public Health Virology, Coopers Plains, Qld 4108, Australia; (S.H.-M.); (J.M.); (G.H.); (N.N.); (J.B.)
| | - Neelima Nair
- Queensland Health, Forensic and Scientific Services, Public Health Virology, Coopers Plains, Qld 4108, Australia; (S.H.-M.); (J.M.); (G.H.); (N.N.); (J.B.)
| | - Jean Barcelon
- Queensland Health, Forensic and Scientific Services, Public Health Virology, Coopers Plains, Qld 4108, Australia; (S.H.-M.); (J.M.); (G.H.); (N.N.); (J.B.)
| | - Willy W. Suen
- School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, Qld 4072, Australia (C.A.O.); (W.W.S.); (J.H.-P.)
| | - Lorna Melville
- Berrimah Veterinary Laboratories, NT 0828, Australia; (S.S.D.); (L.M.)
| | - Jody Hobson-Peters
- School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, Qld 4072, Australia (C.A.O.); (W.W.S.); (J.H.-P.)
- Australian Infectious Diseases Centre, University of Queensland, St Lucia, Qld 4072, Australia
| | - Roy A. Hall
- School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, Qld 4072, Australia (C.A.O.); (W.W.S.); (J.H.-P.)
- Australian Infectious Diseases Centre, University of Queensland, St Lucia, Qld 4072, Australia
- Correspondence: (R.A.H.); (S.R.I.); (H.B.-O.)
| | - Sally R. Isberg
- Centre for Crocodile Research, Noonamah, NT 0837, Australia;
- Correspondence: (R.A.H.); (S.R.I.); (H.B.-O.)
| | - Helle Bielefeldt-Ohmann
- School of Veterinary Science, University of Queensland, Gatton, Qld 4343, Australia;
- School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, Qld 4072, Australia (C.A.O.); (W.W.S.); (J.H.-P.)
- Australian Infectious Diseases Centre, University of Queensland, St Lucia, Qld 4072, Australia
- Correspondence: (R.A.H.); (S.R.I.); (H.B.-O.)
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Crocodilepox Virus Evolutionary Genomics Supports Observed Poxvirus Infection Dynamics on Saltwater Crocodile ( Crocodylus porosus). Viruses 2019; 11:v11121116. [PMID: 31810339 PMCID: PMC6950651 DOI: 10.3390/v11121116] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 11/04/2019] [Accepted: 11/29/2019] [Indexed: 12/18/2022] Open
Abstract
Saltwater crocodilepox virus (SwCRV), belonging to the genus Crocodylidpoxvirus, are large DNA viruses posing an economic risk to Australian saltwater crocodile (Crocodylus porosus) farms by extending production times. Although poxvirus-like particles and sequences have been confirmed, their infection dynamics, inter-farm genetic variability and evolutionary relationships remain largely unknown. In this study, a poxvirus infection dynamics study was conducted on two C. porosus farms. One farm (Farm 2) showed twice the infection rate, and more concerningly, an increase in the number of early- to late-stage poxvirus lesions as crocodiles approached harvest size, reflecting the extended production periods observed on this farm. To determine if there was a genetic basis for this difference, 14 complete SwCRV genomes were isolated from lesions sourced from five Australian farms. They encompassed all the conserved genes when compared to the two previously reported SwCRV genomes and fell within three major clades. Farm 2′s SwCRV sequences were distributed across all three clades, highlighting the likely mode of inter-farm transmission. Twenty-four recombination events were detected, with one recombination event resulting in consistent fragmentation of the P4c gene in the majority of the Farm 2 SwCRV isolates. Further investigation into the evolution of poxvirus infection in farmed crocodiles may offer valuable insights in evolution of this viral family and afford the opportunity to obtain crucial information into natural viral selection processes in an in vivo setting.
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