1
|
Miaud C, Arnal V, Poulain M, Valentini A, Dejean T. eDNA Increases the Detectability of Ranavirus Infection in an Alpine Amphibian Population. Viruses 2019; 11:E526. [PMID: 31174349 PMCID: PMC6631829 DOI: 10.3390/v11060526] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 05/23/2019] [Accepted: 06/04/2019] [Indexed: 01/12/2023] Open
Abstract
The early detection and identification of pathogenic microorganisms is essential in order to deploy appropriate mitigation measures. Viruses in the Iridoviridae family, such as those in the Ranavirus genus, can infect amphibian species without resulting in mortality or clinical signs, and they can also infect other hosts than amphibian species. Diagnostic techniques allowing the detection of the pathogen outside the period of host die-off would thus be of particular use. In this study, we tested a method using environmental DNA (eDNA) on a population of common frogs (Rana temporaria) known to be affected by a Ranavirus in the southern Alps in France. In six sampling sessions between June and September (the species' activity period), we collected tissue samples from dead and live frogs (adults and tadpoles), as well as insects (aquatic and terrestrial), sediment, and water. At the beginning of the breeding season in June, one adult was found dead; at the end of July, a mass mortality of tadpoles was observed. The viral DNA was detected in both adults and tadpoles (dead or alive) and in water samples, but it was not detected in insects or sediment. In live frog specimens, the virus was detected from June to September and in water samples from August to September. Dead tadpoles that tested positive for Ranavirus were observed only on one date (at the end of July). Our results indicate that eDNA can be an effective alternative to tissue/specimen sampling and can detect Ranavirus presence outside die-offs. Another advantage is that the collection of water samples can be performed by most field technicians. This study confirms that the use of eDNA can increase the performance and accuracy of wildlife health status monitoring and thus contribute to more effective surveillance programs.
Collapse
Affiliation(s)
- Claude Miaud
- CEFE, EPHE-PSL, CNRS, Univ. Montpellier, Univ Paul Valéry Montpellier 3, IRD, Biogeography and Vertebrate Ecology, 1919 route de Mende, 34293 Montpellier, France.
| | - Véronique Arnal
- CEFE, EPHE-PSL, CNRS, Univ. Montpellier, Univ Paul Valéry Montpellier 3, IRD, Biogeography and Vertebrate Ecology, 1919 route de Mende, 34293 Montpellier, France.
| | - Marie Poulain
- CEFE, EPHE-PSL, CNRS, Univ. Montpellier, Univ Paul Valéry Montpellier 3, IRD, Biogeography and Vertebrate Ecology, 1919 route de Mende, 34293 Montpellier, France.
| | - Alice Valentini
- SPYGEN, 17 Rue du Lac Saint-André, 73370 Le Bourget-du-Lac, France.
| | - Tony Dejean
- SPYGEN, 17 Rue du Lac Saint-André, 73370 Le Bourget-du-Lac, France.
| |
Collapse
|
2
|
GREEN TREE FROG ( HYLA CINEREA) AND GROUND SQUIRREL ( XEROSPERMOPHILUS SPILOSOMA) MORTALITY ATTRIBUTED TO INLAND BREVETOXIN TRANSPORT AT PADRE ISLAND NATIONAL SEASHORE, TEXAS, USA, 2015. J Wildl Dis 2017; 54:142-146. [PMID: 28829928 DOI: 10.7589/2017-01-018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
: On 16 September 2015, a red tide ( Karenia brevis) bloom impacted coastal areas of Padre Island National Seashore Park, Texas, US. Two days later and about 0.9 km inland, 30-40 adult green tree frogs ( Hyla cinerea) were found dead after displaying tremors, weakness, labored breathing, and other signs of neurologic impairment. A rainstorm accompanied by high winds, rough surf, and high tides, which could have aerosolized brevetoxin, occurred on the morning of the mortality event. Frog carcasses were in good body condition but contained significant brevetoxin in tissues. Tissue brevetoxin was also found in two dead or dying spotted ground squirrels ( Xerospermophilus spilosoma) and a coyote ( Canis latrans) found in the area. Rainwater collected from the location of the mortality event contained brevetoxin. Green tree frog and ground squirrel mortality has not been previously attributed to brevetoxin exposure and such mortality suggested that inland toxin transport, possibly through aerosols, rainfall, or insects, may have important implications for coastal species.
Collapse
|
3
|
Landsberg JH, Kiryu Y, Tabuchi M, Waltzek TB, Enge KM, Reintjes-Tolen S, Preston A, Pessier AP. Co-infection by alveolate parasites and frog virus 3-like ranavirus during an amphibian larval mortality event in Florida, USA. DISEASES OF AQUATIC ORGANISMS 2013; 105:89-99. [PMID: 23872853 DOI: 10.3354/dao02625] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A multispecies amphibian larval mortality event, primarily affecting American bullfrogs Lithobates catesbeianus, was investigated during April 2011 at the Mike Roess Gold Head Branch State Park, Clay County, Florida, USA. Freshly dead and moribund tadpoles had hemorrhagic lesions around the vent and on the ventral body surface, with some exhibiting a swollen abdomen. Bullfrogs (100%), southern leopard frogs L. sphenocephalus (33.3%), and gopher frogs L. capito (100%) were infected by alveolate parasites. The intensity of infection in bullfrog livers was high. Tadpoles were evaluated for frog virus 3 (FV3) by histology and PCR. For those southern leopard frog tadpoles (n = 2) whose livers had not been obscured by alveolate spore infection, neither a pathologic response nor intracytoplasmic inclusions typically associated with clinical infections of FV3-like ranavirus were noted. Sequencing of a portion (496 bp) of the viral major capsid protein gene confirmed FV3-like virus in bullfrogs (n = 1, plus n = 6 pooled) and southern leopard frogs (n = 1, plus n = 4 pooled). In July 2011, young-of-the-year bullfrog tadpoles (n = 7) were negative for alveolate parasites, but 1 gopher frog tadpole was positive. To our knowledge, this is the first confirmed mortality event for amphibians in Florida associated with FV3-like virus, but the extent to which the virus played a primary role is uncertain. Larval mortality was most likely caused by a combination of alveolate parasite infections, FV3-like ranavirus, and undetermined etiological factors.
Collapse
Affiliation(s)
- Jan H Landsberg
- Florida Fish and Wildlife Conservation Commission, St. Petersburg, FL 33701, USA.
| | | | | | | | | | | | | | | |
Collapse
|
4
|
Hoverman JT, Gray MJ, Miller DL, Haislip NA. Widespread occurrence of ranavirus in pond-breeding amphibian populations. ECOHEALTH 2012; 9:36-48. [PMID: 22173292 DOI: 10.1007/s10393-011-0731-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2011] [Revised: 10/30/2011] [Accepted: 11/28/2011] [Indexed: 05/31/2023]
Abstract
Ranaviruses are an emerging threat for many amphibian populations, yet their distribution in amphibian communities and the association of infection with possible stressors and species is not fully understood due to historically sparse surveillance. Agricultural practices that reduce the water quality of amphibian breeding habitats (e.g., cattle access to wetlands) and environmental stressors (e.g., lower temperatures) may contribute to ranavirus emergence. We tested larval amphibians for ranavirus infection across four seasons in farm ponds (n = 40) located in Tennessee, USA. Cattle at various densities were allowed access to half of the sampled ponds. Ranavirus infections were detected in nine species and in 33 of the sampled ponds (83%), illustrating widespread occurrence of the pathogen. Species within the family Ranidae were the most frequently infected. In 13 of the ponds containing infected individuals, prevalence exceeded 40% during at least one season. Infections were detected in multiple seasons in 20 of the sampled ponds containing infections, suggesting that ranaviruses are relatively persistent in these systems. Cattle had negative effects on water quality (turbidity and ammonia) and there was a positive association between cattle abundance and ranavirus prevalence in the summer. Counter to previous field studies in North America, we found a significant positive association between water temperature and ranavirus prevalence in the fall sampling events. Despite these findings, the influences of cattle and temperature on ranavirus prevalence were not consistent across seasons. As such, the mechanisms driving high ranavirus prevalence across the landscape and over time remain unclear. Given the widespread occurrence of ranaviruses in wild amphibians, we encourage the implementation of surveillance programs to help identify potential drivers of emergence. Sites with high ranavirus prevalence should be monitored annually for outbreaks, and the long-term effects on population size determined.
Collapse
Affiliation(s)
- Jason T Hoverman
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309, USA.
| | | | | | | |
Collapse
|
5
|
Ecopathology of ranaviruses infecting amphibians. Viruses 2011; 3:2351-2373. [PMID: 22163349 PMCID: PMC3230856 DOI: 10.3390/v3112351] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 11/03/2011] [Accepted: 11/10/2011] [Indexed: 12/19/2022] Open
Abstract
Ranaviruses are capable of infecting amphibians from at least 14 families and over 70 individual species. Ranaviruses infect multiple cell types, often culminating in organ necrosis and massive hemorrhaging. Subclinical infections have been documented, although their role in ranavirus persistence and emergence remains unclear. Water is an effective transmission medium for ranaviruses, and survival outside the host may be for significant duration. In aquatic communities, amphibians, reptiles and fish may serve as reservoirs. Controlled studies have shown that susceptibility to ranavirus infection and disease varies among amphibian species and developmental stages, and likely is impacted by host-pathogen coevolution, as well as, exogenous environmental factors. Field studies have demonstrated that the likelihood of epizootics is increased in areas of cattle grazing, where aquatic vegetation is sparse and water quality is poor. Translocation of infected amphibians through commercial trade (e.g., food, fish bait, pet industry) contributes to the spread of ranaviruses. Such introductions may be of particular concern, as several studies report that ranaviruses isolated from ranaculture, aquaculture, and bait facilities have greater virulence (i.e., ability to cause disease) than wild-type isolates. Future investigations should focus on the genetic basis for pathogen virulence and host susceptibility, ecological and anthropogenic mechanisms contributing to emergence, and vaccine development for use in captive populations and species reintroduction programs.
Collapse
|
6
|
Ohlemeyer S, Holopainen R, Tapiovaara H, Bergmann SM, Schütze H. Major capsid protein gene sequence analysis of the Santee-Cooper ranaviruses DFV, GV6, and LMBV. DISEASES OF AQUATIC ORGANISMS 2011; 96:195-207. [PMID: 22132498 DOI: 10.3354/dao02370] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The Santee-Cooper ranaviruses doctor fish virus (DFV), guppy virus 6 (GV6), and largemouth bass virus (LMBV) are members of the genus Ranavirus within the family Iridoviridae. The major capsid protein (MCP) is a main structural protein of iridoviruses and supports the differentiation and classification of ranaviruses. Presently the complete sequence of the MCP gene is known for most ranaviruses with the exception of the Santee-Cooper ranaviruses. In the present study, the complete nucleotide sequence of the MCP gene of DFV, GV6, and LMBV was determined. DFV and GV6 are identical within the MCP gene sequence. The identity compared to the corresponding sequence in LMBV amounts to 99.21%. The MCP gene of DFV, GV6, and LMBV exhibits only approximately 78% identity compared to the respective gene of other ranaviruses. Based on the sequence data obtained in the present study, a Rana MCP polymerase chain reaction (PCR) and subsequent restriction fragment length polymorphism (RFLP) analysis were developed to identify and differentiate ranaviruses, including DFV, GV6, and LMBV.
Collapse
Affiliation(s)
- S Ohlemeyer
- Institute of Infectology, Federal Research Institute for Animal Health, Friedrich-Loeffler-Institut, Südufer 10, 17493 Greifswald-Insel Riems, Germany.
| | | | | | | | | |
Collapse
|
7
|
Hoverman JT, Gray MJ, Haislip NA, Miller DL. Phylogeny, life history, and ecology contribute to differences in amphibian susceptibility to ranaviruses. ECOHEALTH 2011; 8:301-19. [PMID: 22071720 DOI: 10.1007/s10393-011-0717-7] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2011] [Revised: 09/27/2011] [Accepted: 10/11/2011] [Indexed: 05/23/2023]
Abstract
Research that identifies the potential host range of generalist pathogens as well as variation in host susceptibility is critical for understanding and predicting the dynamics of infectious diseases within ecological communities. Ranaviruses have been linked to amphibian die-off events worldwide with the greatest number of reported mortality events occurring in the United States. While reports of ranavirus-associated mortality events continue to accumulate, few data exist comparing the relative susceptibility of different species. Using a series of laboratory exposure experiments and comparative phylogenetics, we compared the susceptibilities of 19 amphibian species from two salamander families and five anurans families for two ranavirus isolates: frog virus 3 (FV3) and an FV3-like isolate from an American bullfrog culture facility. We discovered that ranaviruses were capable of infecting 17 of the 19 larval amphibian species tested with mortality ranging from 0 to 100%. Phylogenetic comparative methods demonstrated that species within the anuran family Ranidae were generally more susceptible to ranavirus infection compared to species from the other five families. We also found that susceptibility to infection was associated with species that breed in semi-permanent ponds, develop rapidly as larvae, and have limited range sizes. Collectively, these results suggest that phylogeny, life history characteristics, and habitat associations of amphibians have the potential to impact susceptibility to ranaviruses.
Collapse
Affiliation(s)
- Jason T Hoverman
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309, USA.
| | | | | | | |
Collapse
|