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treatment of amphibians infected with chytrid fungus: learning from failed trials with itraconazole, antimicrobial peptides, bacteria, and heat therapy.amphibian conservation goals depend on effective disease-treatment protocols. desirable protocols are species, life stage, and context specific, but currently few treatment options exist for amphibians infected with the chytrid fungus batrachochytrium dendrobatidis (bd). treatment options, at present, include antifungal drugs and heat therapy, but risks of toxicity and side-effects make these options untenable in some cases. here, we report on the comparison of several novel treatments with a mo ...201222422126
fast quantitative pcr, locked nucleic acid probes and reduced volume reactions are effective tools for detecting batrachochytrium dendrobatidis dna.the fungal pathogen batrachochytrium dendrobatidis threatens amphibian populations around the world. the ability to detect this pathogen on infected animals and in the environment is critical for understanding and controlling this pandemic. we tested several advances in quantitative pcr (qpcr) techniques to detect b. dendrobatidis dna. we used a fast pcr thermocycler and enzymes that reduced the volume and the duration of the reaction. we also compared a conventional taqman minor groove binding ...201222422095
evaluation of a filtration-based method for detecting batrachochytrium dendrobatidis in natural bodies of water.infectious diseases are emerging as a significant threat to wildlife. the resulting increased effort to monitor wildlife diseases is driving the development of innovative pathogen monitoring techniques, including many polymerase chain reaction (pcr)-based diagnostics. despite the utility of these pcr-based techniques, there is still much to be learned about their ability to accurately detect target pathogens in nature. we assessed the diagnostic sensitivity of a pcr-based water filtration techni ...201222422089
interaction between breeding habitat and elevation affects prevalence but not infection intensity of batrachochytrium dendrobatidis in brazilian anuran assemblages.chytridiomycosis, an infectious disease of amphibians, is caused by the fungus batrachochytrium dendrobatidis (bd) and has been linked to declining amphibian populations worldwide. the susceptibility of amphibians to chytridiomycosis-induced population declines is potentially influenced by many factors, including environmental characteristics, differences among host species and the growth of the pathogen itself. we investigated the effects of elevation and breeding habitat on bd prevalence and i ...201222422088
batrachochytrium dendrobatidis shows high genetic diversity and ecological niche specificity among haplotypes in the maya mountains of belize.the amphibian pathogen batrachochytrium dendrobatidis (bd) has been implicated in amphibian declines around the globe. although it has been found in most countries in central america, its presence has never been assessed in belize. we set out to determine the range, prevalence, and diversity of bd using quantitative pcr (qpcr) and sequencing of a portion of the 5.8 s and its1-2 regions. swabs were collected from 524 amphibians of at least 26 species in the protected areas of the maya mountains o ...201222389681
urinary corticosterone metabolites and chytridiomycosis disease prevalence in a free-living population of male stony creek frogs (litoria wilcoxii).the emerging amphibian disease chytridiomycosis, which is caused by the fungal pathogen (batrachochytrium dendrobatidis, bd), has caused mass mortalities of native amphibian populations globally. there have been no previous studies on the relationships between stress hormones in free-living amphibians and bd infections. in this study, we measured urinary corticosterone metabolite concentrations and bd infections within free-living populations of male stony creek frog (litoria wilcoxii) in queens ...201222387450
only skin deep: shared genetic response to the deadly chytrid fungus in susceptible frog species.amphibian populations around the world are threatened by an emerging infectious pathogen, the chytrid fungus batrachochytrium dendrobatidis (bd). how can a fungal skin infection kill such a broad range of amphibian hosts? and do different host species have a similar response to bd infection? here, we use a genomics approach to understand the genetic response of multiple susceptible frog species to bd infection. we characterize the transcriptomes of two closely related endangered frog species (ra ...201222332717
fluorescent microscopy of viable batrachochytrium dendrobatidis.batrachochytrium dendrobatidis ( bd ), a chytrid fungus, is a causative agent of chytridiomycosis and amphibian population declines worldwide. the sequenced genome of bd provides information necessary for studying the fungus and its molecular biology. fluorescent microscopy is a technique used to image targeted molecules in live or fixed organisms to understand cellular trafficking and localization, but the use of fluorescent microscopy with bd has not yet been demonstrated. two fluorescent stai ...201222257116
the impact of pesticides on the pathogen batrachochytrium dendrobatidis independent of potential hosts.amphibians around the world are experiencing the greatest organismal decline in recent history. xenobiotics, such as pesticides, and pathogenic biotic perturbations, including the fungus batrachochytrium dendrobatidis (bd), have played major roles in amphibian decreases. we conducted laboratory culture studies to determine the effects of three pesticides {carbaryl, glyphosate, and thiophanate-methyl [tm; topsin-m(r) (cerexagri-nisso llc)]} on bd zoospore production and zoosporangia growth. we ap ...201222228138
techniques for minimizing the effects of pcr inhibitors in the chytridiomycosis assay.chytridiomycosis is an amphibian disease of global conservation concern that is caused by the fungal pathogen batrachochytrium dendrobatidis (bd). since the discovery of bd in 1998, several methods have been used for detection of bd; among these polymerase chain reaction (pcr) from skin swabs is accepted as the best method due to its noninvasiveness, high sensitivity and ease of use. however, pcr is not without problems - to be successful, this technique is dependent upon the presence of nondegr ...201323241137
daphnia predation on the amphibian chytrid fungus and its impacts on disease risk in tadpoles.direct predation upon parasites has the potential to reduce infection in host populations. for example, the fungal parasite of amphibians, batrachochytrium dendrobatidis (bd), is commonly transmitted through a free-swimming zoospore stage that may be vulnerable to predation. potential predators of bd include freshwater zooplankton that graze on organisms in the water column. we tested the ability of two species of freshwater crustacean (daphnia magna and d. dentifera) to consume bd and to reduce ...201324324864
elevation, temperature, and aquatic connectivity all influence the infection dynamics of the amphibian chytrid fungus in adult frogs.infectious diseases can cause population declines and even extinctions. the amphibian chytrid fungus, batrachochytrium dendrobatidis (bd), has caused population declines and extinctions in amphibians on most continents. in the tropics, research on the dynamics of this disease has focused on amphibian populations in mountainous areas. in most of these areas, high and low elevation sites are connected by an assemblage of streams that may transport the infectious stage of the pathogen from high to ...201324324786
duplex real-time pcr for rapid simultaneous detection of batrachochytrium dendrobatidis and batrachochytrium salamandrivorans in amphibian samples.chytridiomycosis is a lethal fungal disease contributing to declines and extinctions of amphibian species worldwide. the currently used molecular screening tests for chytridiomycosis fail to detect the recently described species batrachochytrium salamandrivorans. in this study, we present a duplex real-time pcr that allows the simultaneous detection of b. salamandrivorans and batrachochytrium dendrobatidis. with b. dendrobatidis- and b. salamandrivorans-specific primers and probes, detection of ...201324108616
why does amphibian chytrid (batrachochytrium dendrobatidis) not occur everywhere? an exploratory study in missouri ponds.the amphibian chytrid fungus, batrachochytrium dendrobatidis (bd), is a globally emerging pathogen that has caused widespread amphibian population declines, extirpations, and extinctions. however, bd does not occur in all apparently suitable amphibian populations, even within regions where it is widespread, and it is often unclear why bd occurs in some habitats but not others. in this study, we rigorously surveyed the amphibian and invertebrate biodiversity of 29 ponds in missouri, screened resi ...201324086681
a survey for batrachochytrium dendrobatidis in endangered and highly susceptible vietnamese salamanders (tylototriton spp.).until now, asian amphibians appear to have largely escaped declines driven by chytridiomycosis. vietnamese salamanders that belong to the genus tylototriton are rare and have a patchy distribution in mountainous areas, falling within the proposed environmental envelope of chytrid infections, surrounded by batrachochytrium dendrobatidis infected regions. if these salamanders are susceptible to chytridiomycosis, then their populations could be highly vulnerable after the introduction of b. dendrob ...201324063090
prevalence of batrachochytrium dendrobatidis in 120 archived specimens of lithobates catesbeianus (american bullfrog) collected in california, 1924-2007.the chytrid fungus, batrachochytrium dendrobatidis (bd), has been identified as a major cause of the recent worldwide amphibian decline. numerous species in north america alone are under threat or have succumbed to bd-driven population extinctions. the american bullfrog (lithobates catesbeianus) has been reported as a tolerant carrier of bd. in this report, we used a qpcr assay to test 120 archived american bullfrog specimens collected between 1924 and 2007 in california, usa and baja california ...201324419668
the absence of zoonotic agents in invasive bullfrogs (lithobates catesbeianus) in belgium and the netherlands.exotic invasive bullfrogs (lithobates catesbeianus) are considered to exert a considerable negative impact on native amphibian communities. this can be due to competition and predation, but they are also a notorious source of the infectious diseases chytridiomycosis and ranavirosis, affecting amphibian populations globally. little is known regarding their carriage of other microbial agents that might be transferred to humans or other animals. in this study we determined the occurrence of the amp ...201324162797
larval exposure to predator cues alters immune function and response to a fungal pathogen in post-metamorphic wood frogs.for the past several decades, amphibian populations have been decreasing around the globe at an unprecedented rate. batrachochytrium dendrobatidis (bd), the fungal pathogen that causes chytridiomycosis in amphibians, is contributing to amphibian declines. natural and anthropogenic environmental factors are hypothesized to contribute to these declines by reducing the immunocompetence of amphibian hosts, making them more susceptible to infection. antimicrobial peptides (amps) produced in the granu ...201324147415
the invasive chytrid fungus of amphibians paralyzes lymphocyte responses.the chytrid fungus, batrachochytrium dendrobatidis, causes chytridiomycosis and is a major contributor to global amphibian declines. although amphibians have robust immune defenses, clearance of this pathogen is impaired. because inhibition of host immunity is a common survival strategy of pathogenic fungi, we hypothesized that b. dendrobatidis evades clearance by inhibiting immune functions. we found that b. dendrobatidis cells and supernatants impaired lymphocyte proliferation and induced apop ...201324136969
has the time come for big science in wildlife health?the consequences of wildlife emerging diseases are global and profound with increased burden on the public health system, negative impacts on the global economy, declines and extinctions of wildlife species, and subsequent loss of ecological integrity. examples of health threats to wildlife include batrachochytrium dendrobatidis, which causes a cutaneous fungal infection of amphibians and is linked to declines of amphibians globally; and the recently discovered pseudogymnoascus (geomyces) destru ...201324136386
a fungal pathogen of amphibians, batrachochytrium dendrobatidis, attenuates in pathogenicity with in vitro passages.laboratory investigations into the amphibian chytrid fungus, batrachochytrium dendrobatidis (bd), have accelerated recently, given the pathogen's role in causing the global decline and extinction of amphibians. studies in which host animals were exposed to bd have largely assumed that lab-maintained pathogen cultures retained the infective and pathogenic properties of wild isolates. attenuated pathogenicity is common in artificially maintained cultures of other pathogenic fungi, but to date, it ...201324130895
batrachochytrium dendrobatidis in aquatic caecilians (typhlonectes natans): a series of cases from two institutions.infection with the fungal organism batrachochytrium dendrobatidis was documented in two captive populations of aquatic caecilians (typhlonectes natans), including 24 confiscated animals at the bronx zoo's wildlife health center and two captive-born animals at the phoenix zoo. the animals at the bronx zoo were asymptomatic, and infection was discovered during quarantine polymerase chain reaction screening. both animals at the phoenix zoo were clinically ill, and batrachochytrium dendrobatidis inf ...201324450061
is chytridiomycosis driving darwin's frogs to extinction?darwin's frogs (rhinoderma darwinii and r. rufum) are two species of mouth brooding frogs from chile and argentina that have experienced marked population declines. rhinoderma rufum has not been found in the wild since 1980. we investigated historical and current evidence of batrachochytrium dendrobatidis (bd) infection in rhinoderma spp. to determine whether chytridiomycosis is implicated in the population declines of these species. archived and live specimens of rhinoderma spp., sympatric amph ...201324278196
efficacy of common disinfectants and terbinafine in inactivating the growth of batrachochytrium dendrobatidis in culture.use of disinfectants by biologists, veterinarians, and zoological facilities is a standard biosecurity procedure to prevent contamination and the spread of pathogens. we tested the efficacy of 5 disinfectants and 1 anti-fungal treatment, at 1 and 5 min contact durations, in inactivating batrachochytrium dendrobatidis (bd) grown on tryptone media. our study focused on concentrations of disinfectants known to inactivate ranaviruses, which can be found at the same sites as bd and can concurrently i ...201324270026
susceptibility of the endangered frog dendropsophus meridensis to the pathogenic fungus batrachochytrium dendrobatidis.chytridiomycosis is an emerging disease that has driven some amphibian species to extinction while leaving others apparently unharmed. its causative agent, batrachochytrium dendrobatidis (bd), now persists endemically in many amphibian communities. understanding host species response to bd infection is critical for managing chytridiomycosis because the epidemiology of this disease is host-specific. dendropsophus meridensis is an endangered hylid frog endemic to the venezuelan andes. this species ...201324270025
geographic distribution of the chytrid pathogen batrachochytrium dendrobatidis among mountain amphibians along the italian peninsula.the amphibian chytrid pathogen batrachochytrium dendrobatidis (bd) is considered a major cause of amphibian population declines, particularly in montane areas. here, we investigated the presence and distribution of bd among populations of 3 mid- to high-altitude species spanning the entire italian peninsula (486 individuals from 39 sites overall): the stream frog rana italica, the fire salamander salamandra salamandra gigliolii, and the alpine newt mesotriton alpestris apuanus. we found bd in al ...201324270024
batrachochytrium dendrobatidis in germany: distribution, prevalences, and prediction of high risk areas.in germany, the pathogenic fungus batrachochytrium dendrobatidis (bd) was detected in 11 indigenous frog species, 4 newt species, and 1 salamander species in 64 out of the 181 locations (35%) investigated. among the 3450 samples collected between 2003 and 2011, 284 (8.2%) were positive for bd infections. the highest prevalences were observed in alytes obstetricans (17.8% of individuals, 20% of populations), followed by ichthyosaura alpestris (14.7%, 22.2%), bombina variegata (13.9%, 38.5%), and ...201324270023
chytridiomycosis: a global threat to amphibians.chytridiomycosis, which is caused by batrachochytrium dendrobatidis, is an emerging infectious disease of amphibians. the disease is one of the main causes of the global decline in amphibians. the aetiological agent is ubiquitous, with worldwide distribution, and affects a large number of amphibian species in several biomes. in the last decade, scientific research has substantially increased knowledge of the aetiological agent and the associated infection. however, important epidemiological aspe ...201324761737
variation in thermal performance of a widespread pathogen, the amphibian chytrid fungus batrachochytrium dendrobatidis.rates of growth and reproduction of the pathogens that cause emerging infectious diseases can be affected by local environmental conditions; these conditions can thus influence the strength and nature of disease outbreaks. an understanding of these relationships is important for understanding disease ecology and developing mitigation strategies. widespread emergence of the fungal disease chytridiomycosis has had devastating effects on amphibian populations. the causative pathogen, batrachochytri ...201324023908
pathogenesis, diagnosis, and treatment of amphibian chytridiomycosis.chytridiomycosis, caused by the chytridiomycete fungus, batrachochytrium dendrobatidis, is an important pathogen of amphibians in captivity and is a major concern for global conservation of amphibians. the organism infects keratinized epithelial cells of amphibian skin and causes disease and mortality by interfering with important skin functions, especially electrolyte balance. primary treatments are with antifungal medications applied in a topical bath solution, and itraconazole is the most com ...201324018031
context-dependent amphibian host population response to an invading pathogen.amphibian chytridiomycosis, caused by the chytrid fungus batrachochytrium dendrobatidis (bd), is an emerging infectious disease that widely threatens amphibian biodiversity. however, population-level outcomes following the introduction of the pathogen are highly context dependent and are mediated by a broad suite of biotic and abiotic variables. here, we examine the effect of the introduction of bd on native island populations of the iucn red-listed amphibian species alytes muletensis, the mallo ...201324015523
batrachochytrium salamandrivorans sp. nov. causes lethal chytridiomycosis in amphibians.the current biodiversity crisis encompasses a sixth mass extinction event affecting the entire class of amphibians. the infectious disease chytridiomycosis is considered one of the major drivers of global amphibian population decline and extinction and is thought to be caused by a single species of aquatic fungus, batrachochytrium dendrobatidis. however, several amphibian population declines remain unexplained, among them a steep decrease in fire salamander populations (salamandra salamandra) th ...201324003137
bacterial flora on cascades frogs in the klamath mountains of california.amphibians are experiencing global declines due in part to the infectious disease chytridiomycosis. some symbiotic bacteria residents on frog skin have been shown to inhibit the growth of batrachochytrium dendrobatitis (bd) but few studies have attempted to fully describe the resident bacterial flora of frog skin. we cultured and sequenced 130 bacterial isolates from frogs collected from the california klamath range, recovering predominantly gram-negative bacteria from 20 higher order taxa and 3 ...201323969031
chromosomal copy number variation, selection and uneven rates of recombination reveal cryptic genome diversity linked to pathogenicity.pathogenic fungi constitute a growing threat to both plant and animal species on a global scale. despite a clonal mode of reproduction dominating the population genetic structure of many fungi, putatively asexual species are known to adapt rapidly when confronted by efforts to control their growth and transmission. however, the mechanisms by which adaptive diversity is generated across a clonal background are often poorly understood. we sequenced a global panel of the emergent amphibian pathogen ...201323966879
spatial assessment of amphibian chytrid fungus (batrachochytrium dendrobatidis) in south africa confirms endemic and widespread infection.chytridiomycosis has been identified as a major cause of global amphibian declines. despite widespread evidence of batrachochytrium dendrobatidis infection in south african frogs, sampling for this disease has not focused on threatened species, or whether this pathogen poses a disease risk to these species. this study assessed the occurrence of bd-infection in south african red list species. in addition, all known records of infection from south africa were used to model the ecological niche of ...201323894506
experimental evidence for a cost of resistance to the fungal pathogen, batrachochytrium dendrobatidis, for the palmate newt, lissotriton helveticus.batrachochytrium dendrobatidis (bd), the causative agent of chytridiomycosis, is decimating amphibians worldwide. unsurprisingly, the majority of studies have therefore concentrated on documenting morbidity and mortality of susceptible species and projecting population consequences as a consequence of this emerging infectious disease. currently, there is a paucity of studies investigating the sub-lethal costs of bd in apparently asymptomatic species, particularly in controlled experimental condi ...201323866033
do pathogens become more virulent as they spread? evidence from the amphibian declines in central america.the virulence of a pathogen can vary strongly through time. while cyclical variation in virulence is regularly observed, directional shifts in virulence are less commonly observed and are typically associated with decreasing virulence of biological control agents through coevolution. it is increasingly appreciated, however, that spatial effects can lead to evolutionary trajectories that differ from standard expectations. one such possibility is that, as a pathogen spreads through a naive host po ...201323843393
a novel subtilisin-like serine protease of batrachochytrium dendrobatidis is induced by thyroid hormone and degrades antimicrobial peptides.batrachochytrium dendrobatidis (b. dendrobatidis), a chytrid fungus, is one of the major contributors to the global amphibian decline. the fungus infects both tadpoles and adult amphibians. tadpoles are infected in their keratinized mouthparts, and infected adults exhibit hyperkeratosis and loss of righting reflex. infections of adults may result in death from cardiac arrest in susceptible species. thyroid hormone plays a key role in amphibian metamorphosis. the occurrence of b. dendrobatidis in ...201323809655
efficacy of treatment and long-term follow-up of batrachochytrium dendrobatidis pcr-positive anurans following itraconazole bath treatment.all anuran specimens in the wildlife conservation society's collections testing positive for batrachochytrium dendrobatidis (bd) were treated with itraconazole and then studied after treatment to assess the long-term effects of itraconazole and the drug's effectiveness in eliminating bd carriers. twenty-four individuals and eight colonies of 11 different species (75 total specimens) tested positive for bd via polymerase chain reaction (pcr) on multicollection survey. all positive individuals and ...201323805558
genetic evidence for a high diversity and wide distribution of endemic strains of the pathogenic chytrid fungus batrachochytrium dendrobatidis in wild asian amphibians.population declines and extinctions of amphibians have been attributed to the chytrid fungus batrachochytrium dendrobatidis (bd), especially one globally emerging recombinant lineage ('bd-gpl'). we used pcr assays that target the ribosomal internal transcribed spacer region (its) of bd to determine the prevalence and genetic diversity of bd in south korea, where bd is widely distributed but is not known to cause morbidity or mortality in wild populations. we isolated korean bd strains from nativ ...201323802586
nonmonotonic and monotonic effects of pesticides on the pathogenic fungus batrachochytrium dendrobatidis in culture and on tadpoles.pesticides and the pathogenic fungus batrachochytrium dendrobatidis (bd) co-occur and are implicated in the global decline of amphibians, a highly threatened taxon. here, we investigated the effects of ecologically relevant concentrations of chlorothalonil and atrazine, two of the most commonly used, immunomodulatory pesticides in the united states, on tadpole (osteopilus septentrionalis) survival and bd growth. tadpole survival was unaffected by the pesticides but was reduced by bd. atrazine mo ...201323777241
impact of both desiccation and exposure to an emergent skin pathogen on transepidermal water exchange in the palmate newt lissotriton helveticus .amphibians are the vertebrate group most affected by global change. their highly permeable skin is involved in maintaining homeostasis (e.g. water and electrolyte equilibrium), which makes them particularly vulnerable to climate warming and skin pathogens. this study focused on the impacts of both desiccation (as a potential consequence of climate warming) and exposure to batrachochytrium dendrobatidis (bd), an emergent skin pathogen of amphibians. bd causes chytridiomycosis, a lethal skin disea ...201323759559
non-invasive monitoring of glucocorticoid physiology within highland and lowland populations of native australian great barred frog (mixophyes fasciolatus).this study used non-invasive endocrinology to examine baseline corticosterone at different altitudes in a free-living australian amphibian: the great barred frog (mixophyes fasciolatus). an enzyme immunoassay (eia) was performed on urine samples and validated biologically using an adrenocorticotropic hormone (acth) challenge. frogs were injected with acth on day 0 and recaptures occurred 1-10days post injection. urine samples and body condition measurements were collected from lowland (60m) and ...201323727276
infection and co-infection by the amphibian chytrid fungus and ranavirus in wild costa rican frogs.amphibian populations are globally threatened by emerging infectious diseases, and 2 pathogens in particular are recognized as major threats: the amphibian chytrid fungus batrachochytrium dendrobatidis (bd) and ranaviruses. here, we evaluated the prevalence of infection by bd and ranavirus in an assemblage of frogs from a lowland wet forest in costa rica. we found an overall prevalence of 21.3% for bd and 16.6% for ranavirus, and detected both pathogens widely among our 20 sampled species. we fo ...201323709470
resistance to chytridiomycosis in european plethodontid salamanders of the genus speleomantes.north america and the neotropics harbor nearly all species of plethodontid salamanders. in contrast, this family of caudate amphibians is represented in europe and asia by two genera, speleomantes and karsenia, which are confined to small geographic ranges. compared to neotropical and north american plethodontids, mortality attributed to chytridiomycosis caused by batrachochytrium dendrobatidis (bd) has not been reported for european plethodontids, despite the established presence of bd in their ...201323703511
prevalence of batrachochytrium dendrobatidis in xenopus collected in africa (1871-2000) and in california (2001-2010).international trade of the invasive south african clawed frog (xenopus laevis), a subclinical carrier of the fungal pathogen batrachochytrium dendrobatis (bd) has been proposed as a major means of introduction of bd into naïve, susceptible amphibian populations. the historical presence of bd in the indigenous african population of xenopus is well documented. however, there are no reports documenting the presence of bd in wild xenopus populations in the us, particularly in california where introd ...201323691097
chytridiomycosis and seasonal mortality of tropical stream-associated frogs 15 years after introduction of batrachochytrium dendrobatidis.assessing the effects of diseases on wildlife populations can be difficult in the absence of observed mortalities, but it is crucial for threat assessment and conservation. we performed an intensive capture-mark-recapture study across seasons and years to investigate the effect of chytridiomycosis on demographics in 2 populations of the threatened common mist frog (litoria rheocola) in the lowland wet tropics of queensland, australia. infection prevalence was the best predictor for apparent surv ...201323678872
batrachochytrium dendrobatidis infection and lethal chytridiomycosis in caecilian amphibians (gymnophiona).batrachochytrium dendrobatidis (bd) is commonly termed the 'amphibian chytrid fungus' but thus far has been documented to be a pathogen of only batrachian amphibians (anurans and caudatans). it is not proven to infect the limbless, generally poorly known, and mostly soil-dwelling caecilians (gymnophiona). we conducted the largest qpcr survey of bd in caecilians to date, for more than 200 field-swabbed specimens from five countries in africa and south america, representing nearly 20 species, 12 g ...201323677560
re-isolating batrachochytrium dendrobatidis from an amphibian host increases pathogenicity in a subsequent exposure.controlled exposure experiments can be very informative, however, they are based on the assumption that pathogens maintained on artificial media under long-term storage retain the infective and pathogenic properties of the reproducing pathogen as it occurs in a host. we observed that jel284, an in vitro cultured and maintained isolate of batrachochytrium dendrobatidis (bd), was becoming less infectious with successive uses. we hypothesized that passing an isolate propagated on artificial media t ...201323671564
widespread occurrence of batrachochytrium dendrobatidis in contemporary and historical samples of the endangered bombina pachypus along the italian peninsula.batrachochytrium dendrobatidis is considered a main driver of the worldwide declines and extinctions of amphibian populations. nonetheless, fundamental questions about its epidemiology, including whether it acts mainly as a "lone killer" or in conjunction with other factors, remain largely open. in this paper we analysed contemporary and historical samples of the endangered apennine yellow-bellied toad (bombina pachypus) along the italian peninsula, in order to assess the presence of the pathoge ...201323667603
evaluation of the skin peptide defenses of the oregon spotted frog rana pretiosa against infection by the chytrid fungus batrachochytrium dendrobatidis.population declines due to amphibian chytridiomycosis among selected species of ranid frogs from western north america have been severe, but there is evidence that the oregon spotted frog, rana pretiosa baird and girard, 1853, displays resistance to the disease. norepinephrine-stimulated skin secretions were collected from a non-declining population of r. pretiosa that had been exposed to the causative agent batrachochytrium dendrobatidis. peptidomic analysis led to identification and isolation, ...201323653106
complex history of the amphibian-killing chytrid fungus revealed with genome resequencing data.understanding the evolutionary history of microbial pathogens is critical for mitigating the impacts of emerging infectious diseases on economically and ecologically important host species. we used a genome resequencing approach to resolve the evolutionary history of an important microbial pathogen, the chytrid batrachochytrium dendrobatidis (bd), which has been implicated in amphibian declines worldwide. we sequenced the genomes of 29 isolates of bd from around the world, with an emphasis on no ...201323650365
high occupancy of stream salamanders despite high ranavirus prevalence in a southern appalachians watershed.the interactive effects of environmental stressors and emerging infectious disease pose potential threats to stream salamander communities and their headwater stream ecosystems. to begin assessing these threats, we conducted occupancy surveys and pathogen screening of stream salamanders (family plethodontidae) in a protected southern appalachians watershed in georgia and north carolina, usa. of the 101 salamanders screened for both chytrid fungus (batrachochytrium dendrobatidis) and ranavirus, o ...201323645459
body length of hylodes cf. ornatus and lithobates catesbeianus tadpoles, depigmentation of mouthparts, and presence of batrachochytrium dendrobatidis are related.a fungal pathogen batrachochytrium dendrobatidis (bd), which can cause morbidity and death of anurans, has affected amphibian populations on a worldwide basis. availability of pure cultures of bd isolates is essential for experimental studies to understand the ecology of this pathogen. we evaluated the relationships of body length of hylodes cf. ornatus and lithobates catesbeianus tadpoles to depigmentation of mouthparts and determined if dekeratinization indicated an infection by batrachochytri ...201323644802
the interactive effect of an emerging infectious disease and an emerging contaminant on woodhouse's toad (anaxyrus woodhousii) tadpoles.two factors that influence amphibian population declines are infectious diseases and exposure to anthropogenic contaminants. the authors examined an emerging fungal pathogen, batrachochytrium dendrobatidis (bd), and its interaction with an emerging contaminant, the antimicrobial triclosan. they first conducted a 2 × 2 × 4 factorial study to examine the interactive impacts of dragonfly predator cues, bd, and triclosan (0 µg/l, 10 µg/l, 100 µg/l, and 1000 µg/l) on woodhouse's toad (anaxyrus woodho ...201323637083
host stress response is important for the pathogenesis of the deadly amphibian disease, chytridiomycosis, in litoria caerulea.chytridiomycosis, a disease caused by batrachochytrium dendrobatidis, has contributed to worldwide amphibian population declines; however, the pathogenesis of this disease is still somewhat unclear. previous studies suggest that infection disrupts cutaneous sodium transport, which leads to hyponatremia and cardiac failure. however, infection is also correlated with unexplained effects on appetite, skin shedding, and white blood cell profiles. glucocorticoid hormones may be the biochemical connec ...201323630628
parallels in amphibian and bat declines from pathogenic fungi.pathogenic fungi have substantial effects on global biodiversity, and 2 emerging pathogenic species-the chytridiomycete batrachochytrium dendrobatidis, which causes chytridiomycosis in amphibians, and the ascomycete geomyces destructans, which causes white-nose syndrome in hibernating bats-are implicated in the widespread decline of their vertebrate hosts. we synthesized current knowledge for chytridiomycosis and white-nose syndrome regarding disease emergence, environmental reservoirs, life his ...201323622255
whether the weather drives patterns of endemic amphibian chytridiomycosis: a pathogen proliferation approach.the pandemic amphibian disease chytridiomycosis often exhibits strong seasonality in both prevalence and disease-associated mortality once it becomes endemic. one hypothesis that could explain this temporal pattern is that simple weather-driven pathogen proliferation (population growth) is a major driver of chytridiomycosis disease dynamics. despite various elaborations of this hypothesis in the literature for explaining amphibian declines (e.g., the chytrid thermal-optimum hypothesis) it has no ...201323613783
fitness consequences of infection by batrachochytrium dendrobatidis in northern leopard frogs (lithobates pipiens).the amphibian chytrid fungus, batrachochytrium dendrobatidis (bd), has been linked to amphibian declines and extinctions worldwide. the pathogen has been found on amphibians throughout eastern north america, but has not been associated with mass die-offs in this region. in this study, we conducted laboratory experiments on the effects of bd infection in a putative carrier species, lithobates pipiens, using two estimators of fitness: jumping performance and testes morphology. over the 8-week stud ...201323604643
skin peptides protect juvenile leopard frogs (rana pipiens) against chytridiomycosis.one issue of great concern for the scientific community is the continuing loss of diverse amphibian species on a global scale. amphibian populations around the world are experiencing serious losses due to the chytrid fungus, batrachochytrium dendrobatidis. this pathogen colonizes the skin, leading to the disruption of ionic balance and eventual cardiac arrest. in many species, antimicrobial peptides secreted into the mucus are thought to contribute to protection against colonization by skin path ...201323580715
laboratory tests of antifungal agents to treat tadpoles against the pathogen batrachochytrium dendrobatidis .the fungus batrachochytrium dendrobatidis (bd), which is the etiological agent of the disease chytridiomycosis, is threatening both wild and captive amphibians. while there are some methods of treating amphibians in captivity, no method has yet been shown to be a promising treatment for amphibian populations in natural habitats. here we present the results of a laboratory experiment in which we tested 2 antifungal agents that might be used to treat amphibians in the field. as a first step toward ...201323574705
development and infectious disease in hosts with complex life cycles.metamorphosis is often characterized by profound changes in morphology and physiology that can affect the dynamics of species interactions. for example, the interaction between a pathogen and its host may differ depending on the life stage of the host or pathogen. one pathogen that infects hosts with complex life cycles is the emerging fungal pathogen of amphibians, batrachochytrium dendrobatidis (bd). we sought to determine how conditions at the larval stage can affect variation in development ...201323565288
its1 copy number varies among batrachochytrium dendrobatidis strains: implications for qpcr estimates of infection intensity from field-collected amphibian skin swabs.genomic studies of the amphibian-killing fungus (batrachochytrium dendrobatidis, [bd]) identified three highly divergent genetic lineages, only one of which has a global distribution. bd strains within these linages show variable genomic content due to differential loss of heterozygosity and recombination. the current quantitative polymerase chain reaction (qpcr) protocol to detect the fungus from amphibian skin swabs targets the intergenic transcribed spacer 1 (its1) region using a taqman fluor ...201323555682
experimental evidence for american bullfrog (lithobates catesbeianus) susceptibility to chytrid fungus (batrachochytrium dendrobatidis).the emerging fungal pathogen, batrachochytrium dendrobatidis (bd), has been associated with global amphibian population declines and extinctions. american bullfrogs (lithobates catesbeianus) are widely reported to be a tolerant host and a carrier of bd that spreads the pathogen to less tolerant hosts. here, we examined whether bullfrogs raised from eggs to metamorphosis in outdoor mesocosms were susceptible to bd. we experimentally exposed metamorphic juveniles to bd in the laboratory and compar ...201323539129
characterization of the first batrachochytrium dendrobatidis isolate from the colombian andes, an amphibian biodiversity hotspot.the pathogenic chytrid fungus, batrachochytrium dendrobatidis (bd), constitutes a significant threat to more than 790 amphibian species occurring in colombia. to date there is no molecular or morphological description of strains infecting colombian populations. here we report the genetic and morphological characterization of the first colombian isolate of bd (strain ev001). our goals were threefold: (1) to characterize the morphology of ev001 using light and scanning electron microscopy, (2) to ...201323529763
population recovery following decline in an endangered stream-breeding frog (mixophyes fleayi) from subtropical australia.amphibians have undergone dramatic declines and extinctions worldwide. prominent among these have been the stream-breeding frogs in the rainforests of eastern australia. the amphibian chytrid fungus batrachochytrium dendrobatidis (bd) has been postulated as the primary cause of these declines. we conducted a capture-mark-recapture study over a 7-year period on the endangered fleay's barred frog (mixophyes fleayi) at two independent streams (30 km apart) in order to assess the stability of these ...201323516509
evidence for the introduction of lethal chytridiomycosis affecting wild betic midwife toads (alytes dickhilleni).batrachochytrium dendrobatidis is an unpredictable pathogen for european amphibian species, and existing field surveillance studies likely underestimate the scope of its distribution and effects. mass mortality episodes recorded in europe indicate that investigations of unstudied species should focus on members of the frog family alytidae. here, we report the combined results of a field survey and laboratory observations of field collected alytes dickhilleni. our data support the hypothesis that ...201323494771
screening bacterial metabolites for inhibitory effects against batrachochytrium dendrobatidis using a spectrophotometric assay.certain bacteria present on frog skin can prevent infection by the pathogenic fungus batrachochytrium dendrobatidis (bd), conferring disease resistance. previous studies have used agar-based in vitro challenge assays to screen bacteria for bd-inhibitory activity and to identify candidates for bacterial supplementation trials. however, agar-based assays can be difficult to set up and to replicate reliably. to overcome these difficulties, we developed a semi-quantitative spectrophotometric challen ...201323482387
mapping the global emergence of batrachochytrium dendrobatidis, the amphibian chytrid fungus.the rapid worldwide emergence of the amphibian pathogen batrachochytrium dendrobatidis (bd) is having a profound negative impact on biodiversity. however, global research efforts are fragmented and an overarching synthesis of global infection data is lacking. here, we provide results from a community tool for the compilation of worldwide bd presence and report on the analyses of data collated over a four-year period. using this online database, we analysed: 1) spatial and taxonomic patterns of i ...201323463502
combining ethidium monoazide treatment with real-time pcr selectively quantifies viable batrachochytrium dendrobatidis cells.detection of the lethal amphibian fungus batrachochytrium dendrobatidis relies on pcr-based techniques. although highly accurate and sensitive, these methods fail to distinguish between viable and dead cells. in this study a novel approach combining the dna intercalating dye ethidium monoazide (ema) and real-time pcr is presented that allows quantification of viable b. dendrobatidis cells without the need for culturing. the developed method is able to suppress real-time pcr signals of heat-kille ...201323452953
mitigating amphibian chytridiomycosis with bioaugmentation: characteristics of effective probiotics and strategies for their selection and use.probiotic therapy through bioaugmentation is a feasible disease mitigation strategy based on growing evidence that microbes contribute to host defences of plants and animals. amphibians are currently threatened by the rapid global spread of the pathogen, batrachochytrium dendrobatidis (bd), which causes the disease chytridiomycosis. bioaugmentation of locally occurring protective bacteria on amphibians has mitigated this disease effectively in laboratory trials and one recent field trial. areas ...201323452227
prior infection does not improve survival against the amphibian disease chytridiomycosis.many amphibians have declined globally due to introduction of the pathogenic fungus batrachochytrium dendrobatidis (bd). hundreds of species, many in well-protected habitats, remain as small populations at risk of extinction. currently the only proven conservation strategy is to maintain species in captivity to be reintroduced at a later date. however, methods to abate the disease in the wild are urgently needed so that reintroduced and wild animals can survive in the presence of bd. vaccination ...201323451076
chytridiomycosis in endemic amphibians of the mountain tops of the córdoba and san luis ranges, argentina.chytridiomycosis is a major threat to amphibian conservation. in argentina, the pathogenic fungus batrachochytrium dendrobatidis has been recorded in several localities, and recently, it was registered in amphibians inhabiting low-elevation areas of mountain environments in córdoba and san luis provinces. in the present study, we searched for b. dendrobatidis in endemic and non-endemic amphibians on the mountain tops of córdoba and san luis provinces. we collected dead amphibians in the upper ve ...201323446975
batrachochytrium dendrobatidis in amphibians of cameroon, including first records for caecilians.amphibian chytrid fungus batrachochytrium dendrobatidis (bd) has been hypothesised to be an indigenous parasite of african amphibians. in cameroon, however, previous surveys in one region (in the northwest) failed to detect this pathogen, despite the earliest african bd having been recorded from a frog in eastern cameroon, plus one recent record in the far southeast. to reconcile these contrasting results, we present survey data from 12 localities across 6 regions of cameroon from anurans (n = 1 ...201323446968
batrachochytrium dendrobatidis haplotypes on the hellbender cryptobranchus alleganiensis are identical to global strains.to determine whether the chytrid fungus batrachochytrium dendrobatidis (bd) found on the hellbender cryptobranchus alleganiensis in the southern us is endemic or exotic, we identified the genetic type of this fungus using partial dna sequences of the internal transcribed spacer (its) region. we identified 3 genetic types, which are found on japanese amphibians other than the japanese giant salamander andrias japonicus, a species that belongs to the same family (cryptobranchidae) as hellbenders. ...201323446967
first survey for the amphibian chytrid fungus batrachochytrium dendrobatidis in connecticut (usa) finds widespread prevalence.the amphibian chytrid fungus batrachochytrium dendrobatidis (bd) is an emerging infectious fungal pathogen of amphibians and is linked to global population declines. until now, there has only been 1 survey for the fungus in the northeastern usa, which focused primarily on northern new england. we tested for bd in a large number of samples (916 individuals from 116 sites) collected throughout the state of connecticut, representing 18 native amphibian species. in addition, 239 preserved wood frog ...201323446966
optimal digestion theory does not predict the effect of pathogens on intestinal plasticity.one prediction of optimal digestion theory is that organisms will increase the relative length of their digestive tracts when food resources become limited. we used theory of optimal digestion to test whether tadpoles can adjust the relative length of their intestines when challenged with the fungal pathogen batrachochytrium dendrobatidis (bd). the degree of tadpole mouthpart damage, a symptom of bd infections that reduces food consumption, was associated positively with the length of tadpole in ...201323445950
west africa - a safe haven for frogs? a sub-continental assessment of the chytrid fungus (batrachochytrium dendrobatidis).a putative driver of global amphibian decline is the panzootic chytrid fungus batrachochytrium dendrobatidis (bd). while bd has been documented across continental africa, its distribution in west africa remains ambiguous. we tested 793 west african amphibians (one caecilian and 61 anuran species) for the presence of bd. the samples originated from seven west african countries - bénin, burkina faso, côte d'ivoire, ghana, guinea, liberia, sierra leone - and were collected from a variety of habitat ...201323426141
a non-invasive stress assay shows that tadpole populations infected with batrachochytrium dendrobatidis have elevated corticosterone levels.batrachochytrium dendrobatidis (bd) is a fungus that causes the disease chytridiomycosis and is associated with widespread amphibian declines. populations vary in their susceptibility to bd infections, and the virulence of the infecting lineage can also vary. both of these factors may manifest as a differential physiological stress response. in addition, variation in disease susceptibility across amphibian populations may be influenced by immunosuppression caused by chronic stress imposed by env ...201323418508
host identity matters in the amphibian-batrachochytrium dendrobatidis system: fine-scale patterns of variation in responses to a multi-host pathogen.species composition within ecological assemblages can drive disease dynamics including pathogen invasion, spread, and persistence. in multi-host pathogen systems, interspecific variation in responses to infection creates important context dependency when predicting the outcome of disease. here, we examine the responses of three sympatric host species to a single fungal pathogen, batrachochytrium dendrobatidis, which is associated with worldwide amphibian population declines and extinctions. usin ...201323382904
lability in host defenses: terrestrial frogs die from chytridiomycosis under enzootic conditions.chytridiomycosis-induced mortalities often occur upon the emergence of batrachochytrium dendrobatidis (bd) in naïve amphibian populations. we report chytridiomycosis-associated mortalities in the wild of the coqui (eleutherodactylus coqui), a declining direct-developing frog with persistent bd infections. these findings provide additional evidence of decreased host defenses during cool-dry seasons in puerto rico.201323307390
mortality of american bullfrog tadpoles lithobates catesbeianus infected by gyrodactylus jennyae and experimentally exposed to batrachochytrium dendrobatidis.the fungal pathogen batrachochytrium dendrobatidis (bd), which causes the disease chytridiomycosis in postmetamorphic amphibians, has been linked to amphibian population declines. different amphibian species, however, exhibit different susceptibility to bd pathogenicity. at the same time, agricultural pesticides commonly found contaminating aquatic habitats have been reported to increase the susceptibility of amphibians to pathogens. to investigate whether certain pesticides are able to alter th ...201323290030
a new treefrog (hylidae: litoria) from kroombit tops, east australia, and an assessment of conservation status.the litoria phyllochroa species-group are small hylid frogs that occur in wet forests of south-east australia. this group has had a long history of taxonomic confusion and has received little attention in the last decade. a population of this species-group at kroombit tops, several hundred kilometers north of all other populations, has been recognised for some time as being genetically highly distinct. here we describe this population as a new species, l. kroombitensis sp. nov. this species is m ...201326213773
climate, vegetation, introduced hosts and trade shape a global wildlife pandemic.global factors, such as climate change, international trade and introductions of exotic species are often elicited as contributors to the unprecedented rate of disease emergence, but few studies have partitioned these factors for global pandemics. although contemporary correlative species distribution models (sdms) can be useful for predicting the spatial patterns of emerging diseases, they focus mainly on the fundamental niche (fn) predictors (i.e. abiotic climate and habitat factors), neglecti ...201323256195
chytrid fungus batrachochytrium dendrobatidis has nonamphibian hosts and releases chemicals that cause pathology in the absence of infection.batrachochytrium dendrobatidis, a pathogenic chytrid fungus implicated in worldwide amphibian declines, is considered an amphibian specialist. identification of nonamphibian hosts could help explain the virulence, heterogeneous distribution, variable rates of spread, and persistence of b. dendrobatidis in freshwater ecosystems even after amphibian extirpations. here, we test whether mosquitofish (gambusia holbrooki) and crayfish (procambarus spp. and orconectes virilis), which are syntopic with ...201323248288
microbial community dynamics and effect of environmental microbial reservoirs on red-backed salamanders (plethodon cinereus).beneficial cutaneous bacteria on amphibians can protect against the lethal disease chytridiomycosis, which has devastated many amphibian species and is caused by the fungus batrachochytrium dendrobatidis. we describe the diversity of bacteria on red-backed salamanders (plethodon cinereus) in the wild and the stability of these communities through time in captivity using culture-independent illumina 16s rrna gene sequencing. after field sampling, salamanders were housed with soil from the field o ...201324335825
selected emerging diseases of amphibia.this review summarizes the most recent updates on emerging infectious diseases of amphibia. a brief summary of batrachochytrium dendrobatidis history, epidemiology, pathogenesis, life cycle, diagnosis, treatment, and biosecurity is provided. ambystoma tigrinum virus, common midwife toad virus, frog virus 3, rana grylio virus, rana catesbeiana ranavirus, mahaffey road virus, rana esculenta virus, bohle iridovirus, and tiger frog virus ranaviruses are extensively reviewed. emerging bacterial patho ...201323642863
interactions between amphibians' symbiotic bacteria cause the production of emergent anti-fungal metabolites.amphibians possess beneficial skin bacteria that protect against the disease chytridiomycosis by producing secondary metabolites that inhibit the pathogen batrachochytrium dendrobatidis (bd). metabolite production may be a mechanism of competition between bacterial species that results in host protection as a by-product. we expect that some co-cultures of bacterial species or strains will result in greater bd inhibition than mono-cultures. to test this, we cultured four bacterial isolates (bacil ...201425191317
cool temperatures reduce antifungal activity of symbiotic bacteria of threatened amphibians--implications for disease management and patterns of decline.chytridiomycosis, caused by the fungus batrachochytrium dendrobatidis (bd), is a widespread disease of amphibians responsible for population declines and extinctions. some bacteria from amphibians' skins produce antimicrobial substances active against bd. supplementing populations of these cutaneous antifungal bacteria might help manage chytridiomycosis in wild amphibians. however, the activity of protective bacteria may depend upon environmental conditions. biocontrol of bd in nature thus requi ...201424941262
partitioning the net effect of host diversity on an emerging amphibian pathogen.the 'dilution effect' (de) hypothesis predicts that diverse host communities will show reduced disease. the underlying causes of pathogen dilution are complex, because they involve non-additive (driven by host interactions and differential habitat use) and additive (controlled by host species composition) mechanisms. here, we used measures of complementarity and selection traditionally employed in the field of biodiversity-ecosystem function (bef) to quantify the net effect of host diversity on ...201425297867
inhibition of batrachochytrium dendrobatidis caused by bacteria isolated from the skin of boreal toads, anaxyrus (bufo) boreas boreas, from grand teton national park, wyoming, usa.the chytrid fungus batrachochytrium dendrobatidis is a significant cause of the worldwide decline in amphibian populations; however, various amphibian species are capable of coexisting with b. dendrobatidis. among them are boreal toads (anaxyrus (bufo) boreas boreas) located in grand teton national park (gtnp) in wyoming, usa. the purpose of this study was to identify cultivable bacterial isolates from the skin microbiota of boreal toads from gtnp and determine if they were capable of inhibiting ...201424826077
the lethal fungus batrachochytrium dendrobatidis is present in lowland tropical forests of far eastern panamá.the fungal disease chytridiomycosis, caused by batrachochytrium dendrobatidis (bd), is one of the main causes of amphibian population declines and extinctions all over the world. in the neotropics, this fungal disease has caused catastrophic declines in the highlands as it has spread throughout central america down to panamá. in this study, we determined the prevalence and intensity of bd infection in three species of frogs in one highland and four lowland tropical forests, including two lowland ...201424740162
immunomodulation in post-metamorphic northern leopard frogs, lithobates pipiens, following larval exposure to polybrominated diphenyl ether.pollutants and disease are factors implicated in amphibian population declines, and it is hypothesized that these factors exert a synergistic adverse effect, which is mediated by pollutant-induced immunosuppression. polybrominated diphenyl ethers (pbdes) are ubiquitous pollutants that can exert immunotoxicity, making them of interest to test effects on amphibian immune function. we orally exposed lithobates (rana) pipiens tadpoles to environmentally realistic levels (0-634 ng/g wet diet) of a pe ...201424735054
reduced itraconazole concentration and durations are successful in treating batrachochytrium dendrobatidis infection in amphibians.amphibians are experiencing the greatest decline of any vertebrate class and a leading cause of these declines is a fungal pathogen, batrachochytrium dendrobatidis (bd), which causes the disease chytridiomycosis. captive assurance colonies are important worldwide for threatened amphibian species and may be the only lifeline for those in critical threat of extinction. maintaining disease free colonies is a priority of captive managers, yet safe and effective treatments for all species and across ...201424686573
fungal infection intensity and zoospore output of atelopus zeteki, a potential acute chytrid supershedder.amphibians vary in their response to infection by the amphibian-killing chytrid fungus, batrachochytrium dendrobatidis (bd). highly susceptible species are the first to decline and/or disappear once bd arrives at a site. these competent hosts likely facilitate bd proliferation because of ineffective innate and/or acquired immune defenses. we show that atelopus zeteki, a highly susceptible species that has undergone substantial population declines throughout its range, rapidly and exponentially i ...201424675899
over-wintering tadpoles of mixophyes fasciolatus act as reservoir host for batrachochytrium dendrobatidis.batrachochytrium dendrobatidis (bd), a cutaneous amphibian fungus that causes the lethal disease chytridiomycosis, has been implicated as a cause of many amphibian declines. bd can tolerate low temperatures with an optimum thermal range from 17-24°c. it has been shown that bd infection may result in species extinction, avoiding the transmission threshold presented by density dependent transmission theory. prevalence of bd during autumn and winter has been shown to be as low as 0% in some species ...201424647532
environmental determinants of recent endemism of batrachochytrium dendrobatidis infections in amphibian assemblages in the absence of disease outbreaks.the inconsistent distribution of large-scale infection mediated die-offs and the subsequent population declines of several animal species, urges us to understand how, when, and why species are affected by disease. it is often unclear when or under what conditions a pathogen constitutes a threat to a host. often, variation of environmental conditions plays a role. globally batrachochytrium dendrobatidis (bd) causes amphibian declines; however, host responses are inconsistent and this fungus appea ...201424641583
stress and chytridiomycosis: exogenous exposure to corticosterone does not alter amphibian susceptibility to a fungal pathogen.recent emergence and spread of the amphibian fungal pathogen, batrachochytrium dendrobatidis (bd) has been attributed to a number of factors, including environmental stressors that increase host susceptibility to bd. physiological stress can increase circulating levels of the hormone, corticosterone, which can alter a host's physiology and affect its susceptibility to pathogens. we experimentally elevated whole-body levels of corticosterone in both larval and post-metamorphic amphibians, and sub ...201424610865
presence of the amphibian chytrid fungus batrachochytrium dendrobatidis in native amphibians exported from madagascar.the emerging infectious disease chytridiomycosis is driven by the spread of amphibian chytrid fungus (batrachochytrium dendrobatidis, bd), a highly virulent pathogen threatening global amphibian biodiversity. although pandemic in distribution, previous intensive field surveys have failed to detect bd in madagascar, a biodiversity hotspot home to hundreds of endemic amphibian species. due to the presence of bd in nearby continental africa and the ecological crisis that can be expected following e ...201424599336
first evidence of amphibian chytrid fungus (batrachochytrium dendrobatidis) and ranavirus in hong kong amphibian trade.the emerging infectious amphibian diseases caused by amphibian chytrid fungus (batrachochytrium dendrobatidis, bd) and ranaviruses are responsible for global amphibian population declines and extinctions. although likely to have been spread by a variety of activities, transcontinental dispersal appears closely associated with the international trade in live amphibians. the territory of hong kong reports frequent, high volume trade in amphibians, and yet the presence of bd and ranavirus have not ...201424599268
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