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Moorhead KA, Adamovicz LA, Allender MC. Development and analytical validation of a novel quantitative PCR assay for the detection of Trachemys herpesvirus 1. J Virol Methods 2024; 327:114941. [PMID: 38599248 DOI: 10.1016/j.jviromet.2024.114941] [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: 12/21/2023] [Revised: 04/04/2024] [Accepted: 04/07/2024] [Indexed: 04/12/2024]
Abstract
Emerging infectious diseases are a threat that contributes to the decline of global chelonian species. Herpesviruses are among the most impactful pathogens described in chelonians and are frequently associated with a range of presentations across hosts with the potential for severe morbidity and mortality. Trachemys herpesvirus 1 (TrHV1) has been reported in red-eared and yellow-bellied sliders (Trachemys scripta elegans and Trachemys scripta scripta, respectively) but is largely understudied. Invasive red-eared sliders may serve as a reservoir for transmission to sympatric native species. This study aimed to develop a sensitive and specific quantitative real-time PCR (qPCR) assay for the detection of TrHV1 DNA to aid in the characterization of the epidemiology of this virus in aquatic turtles. Two TaqMan-MGB FAM-dye labeled primer-probe sets were designed and evaluated using plasmid dilutions. The higher performing assay was specific for TrHV1 DNA and had a linear dynamic range of 1.0 × 107 to 1.0 × 101 copies per reaction with an R2 of 0.999, slope of -3.386, and efficiency of 97.39%. The limit of detection was 101 copies per reaction, and there was no loss of reaction efficiency in the presence of TrHV1-negative chelonian oral-cloacal DNA. Overall, the Trachemys herpesvirus 1 assay meets established criteria for acceptable qPCR assays and will be a valuable tool in characterizing the epidemiology of Trachemys herpesvirus 1 in chelonians.
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Affiliation(s)
- Kaitlin A Moorhead
- Wildlife Epidemiology Lab, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, IL 61802, USA.
| | - Laura A Adamovicz
- Wildlife Epidemiology Lab, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, IL 61802, USA; Veterinary Diagnostic Lab, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, IL 61802, USA
| | - Matthew C Allender
- Wildlife Epidemiology Lab, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, IL 61802, USA; Veterinary Diagnostic Lab, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, IL 61802, USA; Brookfield Zoo, Chicago Zoological Society, Brookfield, IL 60513, USA
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Leineweber C, Marschang RE. Antibodies against Two Testudinid Herpesviruses in Pet Tortoises in Europe. Animals (Basel) 2022; 12:ani12172298. [PMID: 36078018 PMCID: PMC9454543 DOI: 10.3390/ani12172298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 08/23/2022] [Accepted: 09/01/2022] [Indexed: 11/16/2022] Open
Abstract
Herpesviruses are important pathogens of tortoises, and several serologically and genetically distinct virus types have been described in these animals. Virus neutralization testing is commonly used in Europe to determine previous infection with the two types most often found in pet European tortoises, testudinid herpesvirus (TeHV) 1 and 3. In this retrospective study, the results of serological testing for antibodies against each of these viruses in serum or plasma samples from 1728 tortoises were evaluated, and antibody detection rates were compared based on virus type, host species, year, season, and country of origin. Antibodies (titer 2 or higher) against at least one of the two viruses used were detected in a total of 122 (7.06%; 95% CI 5.95−8.37%) of the animals tested. The antibody detection rates differed significantly depending on the tortoise species (p < 0.0001) and the year of sampling (TeHV1 p = 0.0402; TeHV3 p = 0.0482) for both virus types. For TeHV1, antibody detection rates differed significantly (p = 0.0384) by season. The highest detection rate was in summer (5.59%; 95% CI 4.10−7.58%), and the lowest was in fall (1.25%; CI 0.53−2.87%). TeHV1 antibody detection rates did not differ significantly (p = 0.7805) by country, whereas TeHV3 antibody detection rates did (p = 0.0090). The highest detection rate, 12.94% (95% CI 7.38−21.70%), was found in samples from Italy. These results support previous hypotheses on the species’ susceptibility to TeHV1 and 3 and the use of serology as a diagnostic test for the detection of herpesvirus-infected tortoises.
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Leineweber C, Müller E, Marschang RE. Herpesviruses in Captive Chelonians in Europe Between 2016 and 2020. Front Vet Sci 2021; 8:733299. [PMID: 34722701 PMCID: PMC8549816 DOI: 10.3389/fvets.2021.733299] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 09/16/2021] [Indexed: 11/13/2022] Open
Abstract
Herpesviruses are important pathogens in tortoises and turtles, yet little is known about the epidemiology of these viruses. We analyzed herpesviruses detected by PCR in samples from captive chelonians in Europe according to virus strain, host species, year and season in which the animal was tested, and country in which the animal was kept. A total of 4,797 samples submitted to a diagnostic laboratory in Europe between January 2016 and December 2020 were evaluated. Of these, 312 (6.50%) were positive for herpesviruses. The types most commonly found were testudinid herpesvirus (TeHV)1 (143 positive, 45.83%) and TeHV3 (153 positive, 49.04%), but also included TeHV2 (1 positive, 0.32%), TeHV4 (3 positive, 0.96%), Terrapene herpesvirus 1 (7 positive, 2.24%), Trachemys herpesvirus 1 (2 positive, 0.64%), and three previously undescribed herpesviruses (0.96%). Herpesviruses were detected in chelonians in the families Testudinidae, Emydidae, Geoemydidae, and in the suborder Pleurodira. Among the species for which 100 samples or more were available, the highest proportions of positive samples (positivity rates) were found in samples from Horsfield's tortoises (Testudo horsfieldii) (14.96%), and radiated tortoises (Astrochelys radiata) (14.05%). Among tortoises (Testudinidae), viruses were most often detected in the spring, while in emydid turtles (Emydidae) they were most often detected in the summer. A comparison of the positivity rates according to country showed significant differences, with the highest rate in samples from Italy (16.01%). This study indicated possible differences in herpesvirus positivity rates depending on host species, virus strain, year of sampling, season, and country of origin. It provides useful information in further understanding fluctuations in infection rates as well as in helping to guide decision making for herpesvirus diagnostics in chelonian patients. It also provides evidence for the international dispersal of herpesviruses with their hosts through international trade.
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Schüler L, Picquet P, Leineweber C, Dietz J, Müller E, Marschang RE. A testudinid herpesvirus 1 (TeHV1)-associated disease outbreak in a group of Horsfield's tortoises (Testudo horsfieldii). TIERARZTLICHE PRAXIS. AUSGABE K, KLEINTIERE/HEIMTIERE 2021; 49:462-467. [PMID: 34861723 DOI: 10.1055/a-1666-8378] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
In spring 2020, a severe disease outbreak with high morbidity and mortality was observed in a collection of 15 Horsfield's tortoises (Testudo horsfieldii). Affected tortoises showed upper respiratory- and gastrointestinal tract signs, including rhinitis and stomatitis. Testudinid herpesvirus 1 (TeHV1) and Mycoplasma spp. were detected by PCR in oral swabs of affected animals. Histological examination of one deceased animal showed intranuclear inclusion bodies typical for herpesvirus infections in liver, spleen and oesophagus. The virus was likely introduced into the collection 2 years earlier by a clinically healthy Horsfield's tortoise that was tested positive for TeHV1 by PCR.
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Okoh GR, Horwood PF, Whitmore D, Ariel E. Herpesviruses in Reptiles. Front Vet Sci 2021; 8:642894. [PMID: 34026888 PMCID: PMC8131531 DOI: 10.3389/fvets.2021.642894] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 04/06/2021] [Indexed: 12/31/2022] Open
Abstract
Since the 1970s, several species of herpesviruses have been identified and associated with significant diseases in reptiles. Earlier discoveries placed these viruses into different taxonomic groups on the basis of morphological and biological characteristics, while advancements in molecular methods have led to more recent descriptions of novel reptilian herpesviruses, as well as providing insight into the phylogenetic relationship of these viruses. Herpesvirus infections in reptiles are often characterised by non-pathognomonic signs including stomatitis, encephalitis, conjunctivitis, hepatitis and proliferative lesions. With the exception of fibropapillomatosis in marine turtles, the absence of specific clinical signs has fostered misdiagnosis and underreporting of the actual disease burden in reptilian populations and hampered potential investigations that could lead to the effective control of these diseases. In addition, complex life histories, sampling bias and poor monitoring systems have limited the assessment of the impact of herpesvirus infections in wild populations and captive collections. Here we review the current published knowledge of the taxonomy, pathogenesis, pathology and epidemiology of reptilian herpesviruses.
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Affiliation(s)
- God'spower Richard Okoh
- Division of Tropical Health and Medicine, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, Australia
| | - Paul F Horwood
- Division of Tropical Health and Medicine, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, Australia
| | - David Whitmore
- Division of Tropical Health and Medicine, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, Australia
| | - Ellen Ariel
- Division of Tropical Health and Medicine, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, Australia
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Galosi L, Attili AR, Perrucci S, Origgi FC, Tambella AM, Rossi G, Cuteri V, Napoleoni M, Mandolini NA, Perugini G, Loehr VJT. Health assessment of wild speckled dwarf tortoises, CHERSOBIUS SIGNATUS. BMC Vet Res 2021; 17:102. [PMID: 33663511 PMCID: PMC7934230 DOI: 10.1186/s12917-021-02800-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 02/16/2021] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND In free-ranging reptile populations, bacterial, fungal, viral and parasitic pathogens may affect hosts through impairment in movements, thermoregulation, reproduction, survival, and population dynamics. The speckled dwarf tortoise (Chersobius [Homopus] signatus) is a threatened species that is mostly restricted to the Succulent Karoo biome in South Africa, and little information on pathogens of this species is available yet. We derived baseline parameters for five males and five females that were captured to genetically enhance a conservation breeding program in Europe. Upon collection of the tortoises, ticks were removed and identified. Immediately upon arrival in Europe, ocular, nasal, oral and cloacal swabs were taken for viral, bacteriological and mycological examinations. Fecal samples were collected before and 1 month after fenbendazole treatment, and analyzed for parasites. A panel of PCR, aiming to detect herpesviruses, adenoviruses and iridoviruses, was carried out. RESULTS Samples were negative for viruses, while bacteriological examination yielded detectable growth in 82.5% of the swabs with a mean load of 16 × 107 ± 61 × 108 colony forming units (CFU) per swab, representing 34 bacterial species. Cloacal and oral swabs yielded higher detectable growth loads than nasal and ocular swabs, but no differences between sexes were observed. Fungi and yeasts (mean load 5 × 103 ± 13 × 103 CFU/swab) were detected in 25% of the swabs. All pre-treatment fecal samples were positive for oxyurid eggs, ranging from 200 to 2400 eggs per gram of feces, whereas after the treatment a significantly reduced egg count (90-100% reduction) was found in seven out of 10 individuals. One remaining individual showed 29% reduction, and two others had increased egg counts. In five tortoises, Nycthocterus spp. and coccidian oocysts were also identified. Soft ticks were identified as Ornithodoros savignyi. CONCLUSIONS Our baseline data from clinically healthy individuals will help future studies to interpret prevalences of microorganisms in speckled dwarf tortoise populations. The study population did not appear immediately threatened by current parasite presence.
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Affiliation(s)
- Livio Galosi
- School of Biosciences and Veterinary Medicine, University of Camerino, 62024, Matelica, Italy.
| | - Anna Rita Attili
- School of Biosciences and Veterinary Medicine, University of Camerino, 62024, Matelica, Italy
| | - Stefania Perrucci
- Department of Veterinary Science, University of Pisa, 56126, Pisa, Italy
| | - Francesco C Origgi
- Centre for Fish and Wildlife Health (FIWI), DIP, Vetsuisse Faculty, University of Bern, 3001, Bern, Switzerland
| | - Adolfo Maria Tambella
- School of Biosciences and Veterinary Medicine, University of Camerino, 62024, Matelica, Italy
| | - Giacomo Rossi
- School of Biosciences and Veterinary Medicine, University of Camerino, 62024, Matelica, Italy
| | - Vincenzo Cuteri
- School of Biosciences and Veterinary Medicine, University of Camerino, 62024, Matelica, Italy
| | - Maira Napoleoni
- Experimental Zooprophylactic Institute (IZS) of Umbria and Marche 'Togo Rosati', 06126, Perugia, Italy
| | | | - Gianni Perugini
- Experimental Zooprophylactic Institute (IZS) of Umbria and Marche 'Togo Rosati', 06126, Perugia, Italy
| | - Victor J T Loehr
- Dwarf Tortoise Conservation, Kwikstaartpad 1, 3403ZH, IJsselstein, Netherlands
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Raphael BL, Macey SK, Platt SG, Seimon TA, Ossiboff RJ, Horne BD, Gamarra AL, Barrera MG, Lwin T, Soe MM, Aung SH, New SS, Khaing LL, Platt K. Health Screening of Burmese Star Tortoises (Geochelone platynota) Prior to Introduction to the Wild. CHELONIAN CONSERVATION AND BIOLOGY 2019. [DOI: 10.2744/ccb-1353.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Bonnie L. Raphael
- Wildlife Conservation Society, 2300 Southern Boulevard, Bronx, New York 10460 USA [; ; ]
| | - Suzanne K. Macey
- American Museum of Natural History, Central Park West at 79th Street, New York, New York 10024 USA [; ; ]
| | - Steven G. Platt
- Wildlife Conservation Society, 2300 Southern Boulevard, Bronx, New York 10460 USA [; ; ]
| | - Tracie A. Seimon
- Wildlife Conservation Society, 2300 Southern Boulevard, Bronx, New York 10460 USA [; ; ]
| | - Robert J. Ossiboff
- Wildlife Conservation Society, 2300 Southern Boulevard, Bronx, New York 10460 USA [; ; ]
| | - Brian D. Horne
- Wildlife Conservation Society, 2300 Southern Boulevard, Bronx, New York 10460 USA [; ; ]
| | - Ariana L. Gamarra
- American Museum of Natural History, Central Park West at 79th Street, New York, New York 10024 USA [; ; ]
| | - Michelle G. Barrera
- American Museum of Natural History, Central Park West at 79th Street, New York, New York 10024 USA [; ; ]
| | - Tint Lwin
- Turtle Survival Alliance - Myanmar Program, No. 12, Nanrattaw Street, Kamayut Township, Yangon, Myanmar []
| | - Me Me Soe
- Turtle Survival Alliance - Myanmar Program, No. 12, Nanrattaw Street, Kamayut Township, Yangon, Myanmar []
| | - Shwe Htay Aung
- Myanmar Forest Department, Nature and Wildlife Conservation Division, Lawkanandar Wildlife Sanctuary, Bagan, Myanmar
| | - San San New
- Myanmar Forest Department, Nature and Wildlife Conservation Division, Minzontaung Wildlife Sanctuary, Natowgyi, Myanmar
| | - Lay Lay Khaing
- Myanmar Forest Department, Nature and Wildlife Conservation Division, Minzontaung Wildlife Sanctuary, Natowgyi, Myanmar
| | - Kalyar Platt
- Turtle Survival Alliance - Myanmar Program, No. 12, Nanrattaw Street, Kamayut Township, Yangon, Myanmar []
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