| phylogenetic analysis of a frog virus 3-like ranavirus found at a site with recurrent mortality and morbidity events in southeastern ontario, canada: partial major capsid protein sequence alone is not sufficient for fine-scale differentiation. | ranaviruses are emerging pathogens of amphibians. we examined the phylogenetic relationship of ranaviruses from infected lithobates sylvaticus tadpoles 2001-2004 from oliver pond, ontario, canada. the isolates sequenced are primarily frog virus 3-like, but because of sequence convergence, finer-scale analysis based on the major capsid protein was uninformative. | 2013 | 23568931 |
| cellular litaf interacts with frog virus 3 75l protein and alters its subcellular localization. | iridoviruses are a family of large double-stranded dna (dsdna) viruses that are composed of 5 genera, including the lymphocystivirus, ranavirus, megalocytivirus, iridovirus, and chloriridovirus genera. the frog virus 3 (fv3) 75l gene is a nonessential gene that is highly conserved throughout the members of the ranavirus genus but is not found in other iridoviruses. fv3 75l shows high sequence similarity to a conserved domain found in the c terminus of litaf, a small cellular protein with unknown ... | 2013 | 23097445 |
| immune evasion strategies of ranaviruses and innate immune responses to these emerging pathogens. | ranaviruses (rv, iridoviridae) are large double-stranded dna viruses that infect fish, amphibians and reptiles. for ecological and commercial reasons, considerable attention has been drawn to the increasing prevalence of ranaviral infections of wild populations and in aquacultural settings. importantly, rvs appear to be capable of crossing species barriers of numerous poikilotherms, suggesting that these pathogens possess a broad host range and potent immune evasion mechanisms. indeed, while som ... | 2012 | 22852041 |
| susceptibility of xenopus laevis tadpoles to infection by the ranavirus frog-virus 3 correlates with a reduced and delayed innate immune response in comparison with adult frogs. | xenopus laevis adults mount effective immune responses to ranavirus frog virus 3 (fv3) infections and clear the pathogen within 2-3 weeks. in contrast, most tadpoles cannot clear fv3 and succumb to infections within a month. while larval susceptibility has been attributed to ineffective adaptive immunity, the contribution of innate immune components has not been addressed. accordingly, we performed a comprehensive gene expression analysis on fv3-infected tadpoles and adults. in comparison to adu ... | 2012 | 22819836 |
| environmental persistence of amphibian and reptilian ranaviruses. | ranaviruses infect fish, amphibians, and reptiles. the present study was conducted to compare the persistence of amphibian and reptilian ranaviruses in a pond habitat. the 4 viruses used in this study included 2 amphibian ranaviruses, frog virus 3 (fv3, the type species of the genus ranavirus) and an isolate from a frog, and 2 ranaviruses of reptilian origin (from a tortoise and from a gecko). a sandwich germ-carrier technique was used to study the persistence of these viruses in sterile and uns ... | 2012 | 22535867 |
| pathogen richness and abundance predict patterns of adaptive major histocompatibility complex variation in insular amphibians. | the identification of the factors responsible for genetic variation and differentiation at adaptive loci can provide important insights into the evolutionary process and is crucial for the effective management of threatened species. we studied the impact of environmental viral richness and abundance on functional diversity and differentiation of the mhc class ia locus in populations of the black-spotted pond frog (pelophylax nigromaculatus), an iucn-listed species, on 24 land-bridge islands of t ... | 2017 | 28734069 |
| ranavirus phylogenomics: signatures of recombination and inversions among bullfrog ranaculture isolates. | ranaviruses are emerging pathogens of fish, amphibians, and reptiles that threaten aquatic animal industries and wildlife worldwide. our objective was to genetically characterize ranaviruses isolated during separate bullfrog lithobates catesbeianus die-offs that occurred eight years apart on the same north american farm. the earlier outbreak was due to a highly pathogenic strain of common midwife toad virus (cmtv) previously known only from europe and china. the later outbreak was due to a chime ... | 2017 | 28803676 |
| a severe ranavirus outbreak in captive, wild-caught box turtles. | a ranavirus outbreak in a captive population of wild-caught individuals was monitored using clinical evaluations and real-time pcr in 317 wild box turtles held in captivity during translocation. during the 2-year study period, the population experienced 71.6% mortality, suggesting that ranaviruses can rapidly attenuate populations. wide variation in infection rate (7-94% per sampling period) was observed, which may have been driven by clearing and reinfection, adaptive immunity, or imperfect det ... | 2017 | 28766064 |
| ranaviruses and other members of the family iridoviridae: their place in the virosphere. | members of the family iridoviridae, collectively referred to as iridovirids, are large, double-stranded dna-containing viruses that infect invertebrates and cold-blooded (ectothermic) vertebrates. infections in the former often lead to massive levels of virus replication resulting in iridescence of the infected animal and ultimately death. among the latter, infections target a variety of organs and are capable of causing high levels of morbidity and mortality among commercially and ecologically ... | 2017 | 28648249 |
| delineating the roles of cellular and innate antiviral immune parameters mediating ranavirus susceptibility using rainbow trout cell lines. | frog virus 3 is the type species of the ranavirus genus and the causative agent of massive mortalities of aquatic species worldwide. a critical step in limiting virus replication, particularly early in infection, is the innate immune response. presently, little is known regarding what innate immune strategies limit fv3 at the cellular level. to this end, the present study uses two rainbow trout cell lines, rtg-2 and rtgutgc, which demonstrate susceptible and relatively resistant phenotypes to fv ... | 2017 | 28634115 |
| mass mortality of eastern box turtles with upper respiratory disease following atypical cold weather. | emerging infectious diseases cause population declines in many ectotherms, with outbreaks frequently punctuated by periods of mass mortality. it remains unclear, however, whether thermoregulation by ectotherms and variation in environmental temperature is associated with mortality risk and disease progression, especially in wild populations. here, we examined environmental and body temperatures of free-ranging eastern box turtles terrapene carolina during a mass die-off coincident with upper res ... | 2017 | 28425422 |
| effect of imidacloprid on the survival of xenopus tadpoles challenged with wild type frog virus 3. | the sensitivity of amphibians to ranavirus may be increased by exposure to other environmental stressors, including chemical contaminants. neonicotinoid insecticides comprise 27% of the global insecticide market and have been detected in wetlands and other aquatic habitats. the present study focused on the effects of exposure of pre-metamorphic xenopus laevis to the neonicotinoid, imidacloprid (imi) on sensitivity to frog virus 3 (fv3) infection. it was hypothesized that exposure of tadpoles to ... | 0 | 29179150 |
| differentiation-dependent antiviral capacities of amphibian (xenopus laevis) macrophages. | infections by ranaviruses such as frog virus 3 (fv3) are significantly contributing to the worldwide amphibian population declines. notably, amphibian macrophages (mφs) are important to both the fv3 infection strategies and the immune defense against this pathogen. however, the mechanisms underlying amphibian mφ fv3 susceptibility and resistance remain unknown. mφ differentiation is mediated by signaling through the colony-stimulating factor-1 receptor (csf-1r), which is now known to be bound by ... | 2017 | 29259133 |