Publications

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survey for the pathogenic chytrid fungus batrachochytrium dendrobatidis in southwestern north carolina salamander populations.batrachochytrium dendrobatidis is a fungal pathogen responsible for a potentially fatal disease of amphibians. we conducted a survey for b. dendrobatidis in the appalachian mountains of southwestern north carolina, usa, from 10 june to 23 july 23 2009. ventral skin swabs were collected from plethodontid salamanders (n=278) and real-time pcr was performed to test for the presence of b. dendrobatidis. we found no evidence of b. dendrobatidis, suggesting that b. dendrobatidis is absent or present i ...201121441199
effects of atrazine, agricultural runoff, and selected effluents on antimicrobial activity of skin peptides in xenopus laevis.atrazine (technical and formulation), agricultural runoff containing atrazine, and treated sewage and landfill effluents were evaluated for their potential to modulate antimicrobial activity of xenopus laevis skin secretions against the chytrid fungus, batrachochytrium dendrobatidis. this chytrid fungus is implicated in several localized mass mortality events, yet the cause of the susceptibility of amphibians to this newly emergent pathogen is unknown. antimicrobial peptides secreted from dermal ...201121453969
mitigating amphibian disease: strategies to maintain wild populations and control chytridiomycosis.abstract:201121496358
microbial pathogens in the fungal kingdom.the fungal kingdom is vast, spanning ~1.5 to as many as 5 million species diverse as unicellular yeasts, filamentous fungi, mushrooms, lichens, and both plant and animal pathogens. the fungi are closely aligned with animals in one of the six to eight supergroups of eukaryotes, the opisthokonts. the animal and fungal kingdoms last shared a common ancestor ~1 billion years ago, more recently than other groups of eukaryotes. as a consequence of their close evolutionary history and shared cellular m ...201121528015
exposure of juvenile green frogs (lithobates clamitans) in littoral enclosures to a glyphosate-based herbicide.the majority of studies on the toxicity of glyphosate-based herbicides to amphibians have focused on larval life stages exposed in aqueous media. however, adult and juvenile amphibians may also be exposed directly or indirectly to herbicides. the potential for such exposures is of particular interest in the littoral zone surrounding wetlands as this is preferred habitat for many amphibian species. moreover, it may be argued that potential herbicide effects on juvenile or adult amphibians could h ...201121536331
first record of batrachochytrium dendrobatidis infecting four frog families from peninsular malaysia.the fungal pathogen batrachochytrium dendrobatidis (bd) infects amphibians on every continent where they occur and is linked to the decline of over 200 amphibian species worldwide. at present, only three published bd surveys exist for mainland asia, and bd has been detected in south korea alone. in this article, we report the first survey for bd in peninsular malaysia. we swabbed 127 individuals from the six amphibian families that occur on peninsular malaysia, including two orders, 27 genera, a ...201121541819
coincident mass extirpation of neotropical amphibians with the emergence of the infectious fungal pathogen batrachochytrium dendrobatidis.amphibians highlight the global biodiversity crisis because ∼40% of all amphibian species are currently in decline. species have disappeared even in protected habitats (e.g., the enigmatic extinction of the golden toad, bufo periglenes, from costa rica). the emergence of a fungal pathogen, batrachochytrium dendrobatidis (bd), has been implicated in a number of declines that have occurred in the last decade, but few studies have been able to test retroactively whether bd emergence was linked to e ...201121543713
tropical amphibian populations experience higher disease risk in natural habitats.habitat loss and disease are main drivers of global amphibian declines, yet the interaction between them remains largely unexplored. here we show that paradoxically, habitat loss is negatively associated with occurrence, prevalence, and infection intensity of the chytrid fungus batrachochytrium dendrobatidis (bd) in amphibian populations in the tropics. at a large spatial scale, increased habitat loss predicted lower disease risk in amphibian populations across costa rica and eastern australia, ...201121628560
comparison of sensitivity between real-time detection of a taqman assay for batrachochytrium dendrobatidis and conventional detection.a sensitive and quantitative taqman assay for the causative agent of chytridiomycosis in amphibians (batrachochytrium dendrobatidis) has been developed and is routinely used in diagnostic laboratories. we assessed whether the real time detection of the taqman assay was as sensitive as the detection of the pcr product by agarose gel electrophoresis and ethidium bromide staining. we found, for practical purposes, that gel-based detection of the diagnostic fragment produced by means of the taqman a ...201121648238
do frogs get their kicks on route 66? continental u.s. transect reveals spatial and temporal patterns of batrachochytrium dendrobatidis infection.the chytrid fungus batrachochytrium dendrobatidis (bd) has been devastating amphibians globally. two general scenarios have been proposed for the nature and spread of this pathogen: bd is an epidemic, spreading as a wave and wiping out individuals, populations, and species in its path; and bd is endemic, widespread throughout many geographic regions on every continent except antarctica. to explore these hypotheses, we conducted a transcontinental transect of united states department of defense ( ...201121811576
temperature, hydric environment, and prior pathogen exposure alter the experimental severity of chytridiomycosis in boreal toads.prevalence of the pathogen batrachochytrium dendrobatidis (bd), implicated in amphibian population declines worldwide, is associated with habitat moisture and temperature, but few studies have varied these factors and measured the response to infection in amphibian hosts. we evaluated how varying humidity, contact with water, and temperature affected the manifestation of chytridiomycosis in boreal toads anaxyrus (bufo) boreas boreas and how prior exposure to bd affects the likelihood of survival ...201121797033
elevated temperature as a treatment for batrachochytrium dendrobatidis infection in captive frogs.the amphibian chytrid fungus batrachochytrium dendrobatidis (bd) has been implicated in amphibian declines worldwide. in vitro laboratory studies and those done on wild populations indicate that bd grows best at cool temperatures between 17 and 25 degrees c. in the present study, we tested whether moderately elevating the ambient temperature to 30 degrees c could be an effective treatment for frogs infected with bd. we acquired 35 bullfrogs rana catesbeiana from breeding facilities and 36 northe ...201121790070
motile zoospores of batrachochytrium dendrobatidis move away from antifungal metabolites produced by amphibian skin bacteria.chytridiomycosis is an amphibian skin disease that threatens amphibian biodiversity worldwide. the fungal agent of chytridiomycosis is batrachochytrium dendrobatidis. there is considerable variation in disease outcomes such that some individuals and populations co-exist with the fungus and others quickly succumb to disease. amphibians in populations that co-exist with the b. dendrobatidis have sublethal infections on their skins. symbiotic skin bacteria have been shown in experiments and surveys ...201121769695
evidence for acquisition of virulence effectors in pathogenic chytrids.abstract:201121740557
examining the evidence for chytridiomycosis in threatened amphibian species.extinction risks are increasing for amphibians due to rising threats and minimal conservation efforts. nearly one quarter of all threatened/extinct amphibians in the iucn red list is purportedly at risk from the disease chytridiomycosis. however, a closer look at the data reveals that batrachochytrium dendrobatidis (the causal agent) has been identified and confirmed to cause clinical disease in only 14% of these species. primary literature surveys confirm these findings; ruling out major discre ...201121826233
amphibian immune defenses against chytridiomycosis: impacts of changing environments.eco-immunology is the field of study that attempts to understand the functions of the immune system in the context of the host's environment. amphibians are currently suffering devastating declines and extinctions in nearly all parts of the world due to the emerging infectious disease chytridiomycosis caused by the chytrid fungus, batrachochytrium dendrobatidis. because chytridiomycosis is a skin infection and remains confined to the skin, immune defenses of the skin are critical for survival. s ...201121816807
ambient ultraviolet b radiation and prevalence of infection by batrachochytrium dendrobatidis in two amphibian species.ôçé chytridiomycosis, the emerging disease caused by the chytrid fungus batrachochytrium dendrobatidis (bd) is responsible for declines and extirpations of amphibian populations worldwide. environmental covariates modify the host-bd interaction and thus affect the ongoing spread of the pathogen. one such covariate may be the intensity of ultraviolet b (uv-b) radiation. in a field experiment conducted in laguna grande de pe+¦alara (central spain), a mountainous region where the presence of bd has ...201121676032
prevalence of batrachochytrium dendrobatidis in agalychnis moreletii (hylidae) of el salvador and association with larval jaw sheath depigmentation.amphibian populations around the world have been declining at an alarming rate due to factors such as habitat destruction, pollution, and infectious diseases. between may and july 2008, we investigated a fungal pathogen in the critically endangered morelet's treefrog (agalychnis moreletii) at sites in el salvador. larvae were screened with a hand lens for indications of infection with batrachochytrium dendrobatidis (bd), a fungus that can cause lethal chytridiomycosis in amphibians. subsets of i ...201121719819
high prevalence of the amphibian chytrid pathogen in gabon.amphibian chytridiomycosis is an infectious disease caused by the fungus batrachochytrium dendrobatidis (bd) that is implicated in the worldwide decline and extinction of amphibians. africa has been proposed as a potential source for the global expansion of bd, yet the distribution of bd across the continent remains largely unexplored. using quantitative polymerase chain reaction (qpcr), we screened for the presence of bd in 166 adult anurans from two national parks in gabon (monts de cristal an ...201121210295
ubiquity of the pathogenic chytrid fungus, batrachochytrium dendrobatidis, in anuran communities in panamá.the pathogenic chytrid fungus, batrachochytrium dendrobatidis, has been implicated as the main driver of many enigmatic amphibian declines in neotropical sites at high elevation. batrachochytrium dendrobatidis is thought to be a waterborne pathogen limited by temperature, and the extent to which it persists and causes disease in amphibians at lower elevations in the neotropics is not known. it also is unclear by what mechanism(s) b. dendrobatidis has emerged as a pathogenic organism. to test whe ...201121225313
differential host susceptibility toôçébatrachochytrium dendrobatidis, an emerging amphibian pathogen.ôçé the amphibian fungal pathogenôçébatrachochytrium dendrobatidisôçé(bd) has received considerable attention due to its role in amphibian population declines worldwide. although many amphibian species appear to be affected by bd, there is little information on species-specific differences in susceptibility to this pathogen. we used a comparative experimental approach to examine bd susceptibility in 6 amphibian species from the united states. we exposed postmetamorphic animals to bd for 30 days ...201121732979
Growth of the amphibian pathogen, Batrachochytrium dendrobatidis, in response to chemical properties of the aquatic environment.Water samples from two of 17 field sites in Arizona (USA) inhibited growth of the amphibian pathogen, Batrachochytrium dendrobatidis. Chemical analyses of samples revealed statistically significant facilitating or inhibitory activity of certain elements. Although low levels of copper were found in environmental samples demonstrating facilitated growth, growth was inhibited at concentrations of copper sulfate (CuSO(4)) at or greater than 100 ppm.201121719835
new records of batrachochytrium dendrobatidis in chilean frogs.we used molecular techniques to examine 11 species of frogs in 6 localities in southern chile to ascertain the incidence of the chytrid fungus batrachochytrium dendrobatidis (bd). we detected the fungus in 2 localities (coñaripe and raúl marín balmaceda) in 3 species: batrachyla leptopus, pleurodema thaul and rhinoderma darwinii. our findings expand the list of bd hosts to include b. leptopus and p. thaul and extend the spatial distribution in chile to include the southernmost bd record at raúl ...201121932539
varying responses of northeastern north american amphibians to the chytrid pathogen batrachochytrium dendrobatidis.chytridiomycosis, caused by batrachochytrium dendrobatidis (bd), is widespread among amphibians in northeastern north america. it is unknown, however, whether bd has the potential to cause extensive amphibian mortalities in northeastern north america as have occurred elsewhere. in the laboratory, we exposed seven common northeastern north american amphibian species to bd to assess the likelihood of population-level effects from the disease. we exposed larval wood frogs (lithobates sylvaticus) an ...201122181933
historic occurrence of the amphibian chytrid fungus batrachochytrium dendrobatidis in hellbender cryptobranchus alleganiensis populations from missouri.the pathogenic fungus batrachochytrium dendrobatidis (bd) was recently detected in missouri hellbender cryptobranchus alleganiensis populations that have declined precipitously for unclear reasons. the objective of this study was to determine whether bd occurred historically in missouri hellbender populations or is a relatively novel occurrence. epidermal tissue was removed from 216 archived hellbenders collected from 7 missouri streams between 1896 and 1994. histological techniques and an immun ...201121991660
Is chytridiomycosis an emerging infectious disease in Asia?The disease chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd), has caused dramatic amphibian population declines and extinctions in Australia, Central and North America, and Europe. Bd is associated with >200 species extinctions of amphibians, but not all species that become infected are susceptible to the disease. Specifically, Bd has rapidly emerged in some areas of the world, such as in Australia, USA, and throughout Central and South America, causing population and s ...201121887238
dietary protein restriction impairs growth, immunity, and disease resistance in southern leopard frog tadpoles.the immune system is a necessary, but potentially costly, defense against infectious diseases. when nutrition is limited, immune activity may consume a significant amount of an organism's energy budget. levels of dietary protein affect immune system function; high levels can enhance disease resistance. we exposed southern leopard frog [lithobates sphenocephalus (=rana sphenocephala)] tadpoles to high and low protein diets crossed with the presence or absence of the pathogenic amphibian chytrid f ...201122038058
Detection of Batrachochytrium dendrobatidis in Mexican Bolitoglossine Salamanders Using an Optimal Sampling Protocol.The role of the chytrid fungus Batrachochytrium dendrobatidis (Bd), which is the causal agent of chytridiomycosis, in the declines of Central American bolitoglossine salamanders is unknown. Here we establish a swabbing protocol to maximize the detection probability of Bd in salamanders. We then used this protocol to examine captive and wild Mexican bolitoglossine salamanders of 14 different species for the presence of Bd. Of the seven body parts sampled, the pelvic region, hindlimbs, forelimbs, ...201121912986
MHC genotypes associate with resistance to a frog-killing fungus.The emerging amphibian disease chytridiomycosis is caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd). Amphibian populations and species differ in susceptibility to Bd, yet we know surprisingly little about the genetic basis of this natural variation. MHC loci encode peptides that initiate acquired immunity in vertebrates, making them likely candidates for determining disease susceptibility. However, MHC genes have never been characterized in the context of chytridiomycosis. Here, ...201121949385
Fluorescent probes as a tool for labelling and tracking the amphibian chytrid fungus Batrachochytrium dendrobatidis.The dissemination of the virulent pathogen Batrachochytrium dendrobatidis (Bd) has contributed to the decline and extinction of many amphibian species worldwide. Several different strains have been identified, some of which are sympatric. Interactions between co-infecting strains of a pathogen can have significant influences on disease epidemiology and evolution; therefore the dynamics of multi-strain infections is an important area of research. We stained Bd cells with 2 fluorescent BODIPY fatt ...201122013756
nothing a hot bath won't cure: infection rates of amphibian chytrid fungus correlate negatively with water temperature under natural field settings.dramatic declines and extinctions of amphibian populations throughout the world have been associated with chytridiomycosis, an infectious disease caused by the pathogenic chytrid fungus batrachochytrium dendrobatidis (bd). previous studies indicated that bd prevalence correlates with cooler temperatures in the field, and laboratory experiments have demonstrated that bd ceases growth at temperatures above 28°c. here we investigate how small-scale variations in water temperature correlate with bd ...201122205950
frog skin epithelium: electrolyte transport and chytridiomycosis.one unique physiological characteristic of frogs is that their main route for intake of water is across the skin. in these animals, the skin acts in concert with the kidney and urinary bladder to maintain electrolyte homeostasis. water absorption across the skin is driven by the osmotic gradient that develops as a consequence of solute transport. our recent study demonstrated that chytridiomycosis, an infection of amphibian skin by the fungal pathogen, batrachochytrium dendrobatidis, inhibits ep ...201122182598
environmental refuge from disease-driven amphibian extinction.species that are tolerant of broad environmental gradients may be less vulnerable to epizootic outbreaks of disease. chytridriomycosis, caused by the fungus batrachochytrium dendrobatidis, has been linked to extirpations and extinctions of amphibian species in many regions. the pathogen thrives in cool, moist environments, and high amphibian mortality rates have commonly occurred during chytridiomycosis outbreaks in amphibian populations in high-elevation tropical rainforests. in australia sever ...201121902719
a dilution effect in the emerging amphibian pathogen batrachochytrium dendrobatidis.global declines in biodiversity are altering disease dynamics in complex and multifaceted ways. changes in biodiversity can have several outcomes on disease risk, including dilution and amplification effects, both of which can have a profound influence on the effects of disease in a community. the dilution effect occurs when biodiversity and disease risk are inversely related, whereas the amplification effect is a positive relationship between biodiversity and disease risk. we tested these effec ...201121930900
can differences in host behavior drive patterns of disease prevalence in tadpoles?differences in host behavior and resistance to disease can influence the outcome of host-pathogen interactions. we capitalized on the variation in aggregation behavior of fowler's toads (anaxyrus [ = bufo] fowleri) and grey treefrogs (hyla versicolor) tadpoles and tested for differences in transmission of batrachochytrium dendrobatidis (bd) and host-specific fitness consequences (i.e., life history traits that imply fitness) of infection in single-species amphibian mesocosms. on average, a. fowl ...201121949824
Short-term exposure to warm microhabitats could explain amphibian persistence with Batrachochytrium dendrobatidis.Environmental conditions can alter the outcomes of symbiotic interactions. Many amphibian species have declined due to chytridiomycosis, caused by the pathogenic fungus Batrachochytrium dendrobatidis (Bd), but many others persist despite high Bd infection prevalence. This indicates that Bd's virulence is lower, or it may even be a commensal, in some hosts. In the Australian Wet Tropics, chytridiomycosis extirpated Litoria nannotis from high-elevation rain forests in the early 1990 s. Although th ...201122028834
health and habitat quality assessment for the eastern hellbender (cryptobranchus alleganiensis alleganiensis) in indiana, usa.the eastern hellbender (cryptobranchus alleganiensis alleganiensis) has experienced precipitous population declines throughout its range. numerous factors are speculated to be involved, but no empirical evidence has been presented for any. we implemented a population-wide health assessment in indiana, usa, examining both the physical well-being of individuals and the quality of their habitat. physicochemical parameters were analyzed directly in the field and later in the laboratory, when appropr ...201122102654
batrachochytrium dendrobatidis can infect and cause mortality in the nematode caenorhabditis elegans.batrachochytrium dendrobatidis (bd) has been identified as a causative agent in the precipitous decline of amphibians worldwide. studies on the fungus including its ability to infect and kill the host require use of frogs, a precious resource. therefore, the development of an alternate host model to study the virulence of the fungus would be useful. here, we show that bd can cause mortality in the nematode caenorhabditis elegans. incubation of bd with c. elegans resulted ...201122002554
Genomic transition to pathogenicity in chytrid fungi.Understanding the molecular mechanisms of pathogen emergence is central to mitigating the impacts of novel infectious disease agents. The chytrid fungus Batrachochytrium dendrobatidis (Bd) is an emerging pathogen of amphibians that has been implicated in amphibian declines worldwide. Bd is the only member of its clade known to attack vertebrates. However, little is known about the molecular determinants of - or evolutionary transition to - pathogenicity in Bd. Here we sequence the genome of Bd's ...201122072962
Multiple emergences of genetically diverse amphibian-infecting chytrids include a globalized hypervirulent recombinant lineage.Batrachochytrium dendrobatidis (Bd) is a globally ubiquitous fungal infection that has emerged to become a primary driver of amphibian biodiversity loss. Despite widespread effort to understand the emergence of this panzootic, the origins of the infection, its patterns of global spread, and principle mode of evolution remain largely unknown. Using comparative population genomics, we discovered three deeply diverged lineages of Bd associated with amphibians. Two of these lineages were found in mu ...201122065772
polymorphic repetitive loci of the amphibian pathogen batrachochytrium dendrobatidis.batrachochytrium dendrobatidis (bd), the cause of a fatal fungal skin disease of amphibians that has led to massive die-offs, global declines and extinctions, has spread internationally as a pandemic clone with low genetic diversity. a need exists to develop highly polymorphic markers to determine centers of origin and patterns of spread to assist in the development of management strategies. comparison of paralogous sequences, obtained from the 2 sequenced bd genomes, indicates useful levels of ...201122235589
norepinephrine depletion of antimicrobial peptides from the skin glands of xenopus laevis.the dermal granular glands of the south african clawed frog, xenopus laevis, contain antimicrobial peptides (amps) that are secreted following local nerve stimulation. these natural antibiotics are active against bacteria and fungi including batrachochytrium dendrobatidis, a fungal pathogen that causes the skin disease chytridiomycosis. granular gland secretion can be stimulated in the laboratory by norepinephrine injection. we found that two injections of 80nmol/g norepinephrine were necessary ...201122227319
towards a better understanding of the use of probiotics for preventing chytridiomycosis in panamanian golden frogs.populations of native panamanian golden frogs (atelopus zeteki) have collapsed due to a recent chytridiomycosis epidemic. reintroduction efforts from captive assurance colonies are unlikely to be successful without the development of methods to control chytridiomycosis in the wild. in an effort to develop a protective treatment regimen, we treated golden frogs with janthinobacterium lividum, a skin bacterium that has been used to experimentally prevent chytridiomycosis in north american amphibia ...201122328095
reptiles as potential vectors and hosts of the amphibian pathogen batrachochytrium dendrobatidis in panama.chytridiomycosis, the disease caused by batrachochytrium dendrobatidis, is considered to be a disease exclusively of amphibians. however, b. dendrobatidis may also be capable of persisting in the environment, and non-amphibian vectors or hosts may contribute to disease transmission. reptiles living in close proximity to amphibians and sharing similar ecological traits could serve as vectors or reservoir hosts for b. dendrobatidis, harbouring the organism on their skin without succumbing to disea ...201122303629
stability and permanence in gender- and stage-structured models for the boreal toad.the boreal toad bufo boreas boreas, once common in the western usa, is listed as an endangered species in colorado and new mexico, and protected in wyoming. populations have dramatically declined due to the presence of the fungal pathogen batrachochytrium dendrobatidis (bd). a gender- and stage-structured model for the boreal toad is formulated which depends on its life cycle and breeding strategies. in addition, an epizootic model for the spread of bd is formulated. analysis of these models pro ...201122877227
the contribution of skin antimicrobial peptides to the system of innate immunity in anurans.cationic peptides with the propensity to adopt an amphipathic α-helical conformation in a membrane-mimetic environment are synthesized in the skins of many species of anurans (frogs and toads). these peptides frequently display cytolytic activities against a range of pathogenic bacteria and fungi consistent with the idea that they play a role in the host's system of innate immunity. however, the importance of the peptides in the survival strategy of the animal is not clearly understood. it is a ...201120640445
host defense peptides in skin secretions of the oregon spotted frog rana pretiosa: implications for species resistance to chytridiomycosis.population declines due to chytridiomycosis among frogs belonging to the amerana (rana boylii) species group from western north america have been particularly severe. norepinephrine-stimulated skin secretions from the oregon spotted frog rana pretiosa baird and girard, 1853 were collected from individuals that had been previously infected with the causative agent batrachochytrium dendrobatidis but had proved resistant to developing chytridiomycosis. these secretions contained a more diverse arra ...201121295070
effects of an infectious fungus, batrachochytrium dendrobatidis, on amphibian predator-prey interactions.the effects of parasites and pathogens on host behaviors may be particularly important in predator-prey contexts, since few animal behaviors are more crucial for ensuring immediate survival than the avoidance of lethal predators in nature. we examined the effects of an emerging fungal pathogen of amphibians, batrachochytrium dendrobatidis, on anti-predator behaviors of tadpoles of four frog species. we also investigated whether amphibian predators consumed infected prey, and whether b. dendrobat ...201121311771
regional decline of an iconic amphibian associated with elevation, land-use change, and invasive species.ecological theory predicts that species with restricted geographic ranges will have the highest probability of extinction, but species with extensive distributions and high population densities can also exhibit widespread population losses. in the western united states populations of northern leopard frogs (lithobates pipiens)-historically one of the most widespread frogs in north america-have declined dramatically in abundance and geographic distribution. to assess the status of leopard frogs i ...201121342266
developing a safe antifungal treatment protocol to eliminate batrachochytrium dendrobatidis from amphibians.batrachochytrium dendrobatidis is one of the most pathogenic microorganisms affecting amphibians in both captivity and in nature. the establishment of b. dendrobatidis free, stable, amphibian captive breeding colonies is one of the emergency measures that is being taken to save threatened amphibian species from extinction. for this purpose, in vitro antifungal susceptibility testing and the development of efficient and safe treatment protocols are required. in this study, we evaluated the use of ...201120718611
treatment of spontaneous chytridiomycosis in captive amphibians using itraconazole.we performed this study in order to establish an effective, simple and safe treatment for chytridiomycosis. the subjects were 12 amphibians (11 anurans of 4 different species and 1 urodela) diagnosed with chytridiomycosis by clinical signs and a pcr test. a 0.01% aqueous solution of the antifungal agent itraconazole was used to treat the subjects, and we evaluated the efficacy of treatment by 3 methods: clinical signs, direct microscopy and a nested pcr test. a 10-min immersion in a 0.01% aqueou ...201120847538
amphibian pathogens in southeast asian frog trade.amphibian trade is known to facilitate the geographic spread of pathogens. here we assess the health of amphibians traded in southeast asia for food or as pets, focusing on batrachochytrium dendrobatidis (bd), ranavirus and general clinical condition. samples were collected from 2,389 individual animals at 51 sites in lao pdr, cambodia, vietnam and singapore for bd screening, and 74 animals in cambodia and vietnam for ranavirus screening. bd was found in one frog (n = 347) in cambodia and 13 in ...201223404036
changes in cutaneous microbial abundance with sloughing: possible implications for infection and disease in amphibians.the emergence of disease as a significant global threat to amphibian diversity has generated considerable interest in amphibian defenses against cutaneous microbial infection and disease. to date, however, the influence of sloughing on the susceptibility of amphibians to infection and disease has been largely overlooked. to investigate the potential for sloughing to regulate topical microbial loads, the abundance of cultivable cutaneous bacteria and fungi in the cane toad rhinella marina were co ...201223324420
there is no evidence for a temporal link between pathogen arrival and frog extinctions in north-eastern australia.pathogen spread can cause population declines and even species extinctions. nonetheless, in the absence of tailored monitoring schemes, documenting pathogen spread can be difficult. in the case of worldwide amphibian declines the best present understanding is that the chytrid fungus batrachochytrium dendrobatidis (bd) has recently spread, causing amphibian declines and extinction in the process. however, good evidence demonstrating pathogen arrival followed by amphibian decline is rare, and anal ...201223300687
laboratory and field exposure of two species of juvenile amphibians to a glyphosate-based herbicide and batrachochytrium dendrobatidis.herbicides are commonly used in agriculture and silviculture to reduce interspecific competition among plants and thereby enhance crop growth, quality, and volume. internationally, formulations of glyphosate-based herbicides are the most widely used herbicides in both these sectors. a large amount of work has focused on the effects of these herbicides on amphibians. several laboratory and mesocosm studies have demonstrated that various formulations of glyphosate herbicides can be acutely toxic t ...201223262329
surviving chytridiomycosis: differential anti-batrachochytrium dendrobatidis activity in bacterial isolates from three lowland species of atelopus.in the neotropics, almost every species of the stream-dwelling harlequin toads (genus atelopus) have experienced catastrophic declines. the persistence of lowland species of atelopus could be explained by the lower growth rate of batrachochytrium dendrobatidis (bd) at temperatures above 25 °c. we tested the complementary hypothesis that the toads' skin bacterial microbiota acts as a protective barrier against the pathogen, perhaps delaying or impeding the symptomatic phase of chytridiomycosis. w ...201222970314
immune evasion or avoidance: fungal skin infection linked to reduced defence peptides in australian green-eyed treefrogs, litoria serrata.many parasites and pathogens suppress host immunity to maintain infection or initiate disease. on the skin of many amphibians, defensive peptides are active against the fungus batrachochytrium dendrobatidis (bd), the causative agent of the emerging infectious disease chytridiomycosis. we tested the hypothesis that infection with the fungus may be linked to lower levels of defensive peptides. we sampled both ambient (or constitutive) skin peptides on the ventral surface immediately upon capture, ...201223245614
substrate-specific gene expression in batrachochytrium dendrobatidis, the chytrid pathogen of amphibians.determining the mechanisms of host-pathogen interaction is critical for understanding and mitigating infectious disease. mechanisms of fungal pathogenicity are of particular interest given the recent outbreaks of fungal diseases in wildlife populations. our study focuses on batrachochytrium dendrobatidis (bd), the chytrid pathogen responsible for amphibian declines around the world. previous studies have hypothesized a role for several specific families of secreted proteases as pathogenicity fac ...201223185485
higher temperature variability increases the impact of batrachochytrium dendrobatidis and shifts interspecific interactions in tadpole mesocosms.the emergence of amphibian chytridiomycosis, caused by the fungus batrachochytrium dendrobatidis (bd) has led to the decline and extinction of numerous amphibian species. multiple studies have observed links between climatic factors and amphibian declines apparently caused by bd. using outdoor experimental mesocosms, we tested the response of red-legged frog (rana aurora) tadpoles to increased variation in temperature, a component of climate linked to amphibian declines, and bd exposure. we incl ...201223145331
temperature alters reproductive life history patterns in batrachochytrium dendrobatidis, a lethal pathogen associated with the global loss of amphibians.understanding how pathogens respond to changing environmental conditions is a central challenge in disease ecology. the environmentally sensitive fungal pathogen batrachochytrium dendrobatidis (bd), which causes the amphibian disease chytridiomycosis, has spread globally causing amphibian extirpations in a wide variety of climatic regions. to gain an in-depth understanding of bd's responses to temperature, we used an integrative approach, combining empirical laboratory experiments with mathemati ...201223139882
clinical trials with itraconazole as a treatment for chytrid fungal infections in amphibians.due in large part to recent global declines and extinctions, amphibians are the most threatened vertebrate group. captive assurance colonies may be the only lifeline for some rapidly disappearing species. maintaining these colonies free of disease represents a challenge to effective amphibian conservation. the fungal disease chytridiomycosis, caused by the fungus batrachochytrium dendrobatidis (bd), is one of the major contributors to global amphibian declines and also poses a serious threat to ...201223135136
potential influence of plant chemicals on infectivity of batrachochytrium dendrobatidis.we explored whether extracts of trees frequently found associated with amphibian habitats in australia and arizona, usa, may be inhibitory to the fungal pathogen batrachochytrium dendrobatidis (bd), which has been associated with global amphibian declines. we used salamanders ambystoma tigrinum as the model system. salamanders acquired significantly lower loads of bd when exposed on leaves and extracts from the river red gum eucalyptus camaldulensis, and loads were also low in some animals expos ...201223135135
disease risk in temperate amphibian populations is higher at closed-canopy sites.habitat loss and chytridiomycosis (a disease caused by the chytrid fungus batrachochytrium dendrobatidis - bd) are major drivers of amphibian declines worldwide. habitat loss regulates host-pathogen interactions by altering biotic and abiotic factors directly linked to both host and pathogen fitness. therefore, studies investigating the links between natural vegetation and chytridiomycosis require integrative approaches to control for the multitude of possible interactions of biological and envi ...201223118953
concurrent ranavirus and batrachochytrium dendrobatidis infection in captive frogs (phyllobates and dendrobates species), the netherlands, 2012: a first report.a ranavirus infection with concurrent batrachochytrium dendrobatidis infection and mortality in captive phyllobates and dendrobates species is reported. greyish skin with hepato- and reno-megaly were evident. microscopically, batrachochytrium dendrobatidis was present in the stratum corneum of the hyperkeratotic skin. intracytoplasmic inclusion bodies were present in erythrocytes and multiple organs. all samples examined tested positive using pcr for the major capsid protein (mcp) gene of ranavi ...201223102620
tolerance of fungal infection in european water frogs exposed to batrachochytrium dendrobatidis after experimental reduction of innate immune defenses.while emerging diseases are affecting many populations of amphibians, some populations are resistant. determining the relative contributions of factors influencing disease resistance is critical for effective conservation management. innate immune defenses in amphibian skin are vital host factors against a number of emerging pathogens such as ranaviruses and the amphibian chytrid fungus batrachochytrium dendrobatidis (bd). adult water frogs from switzerland (pelophylax esculentus and p. lessonae ...201223088169
pathogen pollution and the emergence of a deadly amphibian pathogen.imagine a single pathogen that is responsible for mass mortality of over a third of an entire vertebrate class. for example, if a single pathogen were causing the death, decline and extinction of 30% of mammal species (including humans), the entire world would be paying attention. this is what has been happening to the world's amphibians - the frogs, toads and salamanders that are affected by the chytrid fungal pathogen, batrachochytrium dendrobatidis (referred to as bd), which are consequently ...201223075064
antibacterial therapeutics for the treatment of chytrid infection in amphibians: columbus's egg?the establishment of safe and effective protocols to treat chytridiomycosis in amphibians is urgently required. in this study, the usefulness of antibacterial agents to clear chytridiomycosis from infected amphibians was evaluated.201223009707
the amphibian chytrid fungus, batrachochytrium dendrobatidis, in fully aquatic salamanders from southeastern north america.little is known about the impact that the pathogenic amphibian chytrid fungus, batrachochytrium dendrobatidis (bd), has on fully aquatic salamander species of the eastern united states. as a first step in determining the impacts of bd on these species, we aimed to determine the prevalence of bd in wild populations of fully aquatic salamanders in the genera amphiuma, necturus, pseudobranchus, and siren. we sampled a total of 98 salamanders, representing nine species from sites in florida, mississ ...201222984569
host invasion by batrachochytrium dendrobatidis: fungal and epidermal ultrastructure in model anurans.the chytridiomycete fungus batrachochytrium dendrobatidis (bd) colonizes mouthparts of amphibian larvae and superficial epidermis of post-metamorphic amphibians, causing the disease chytridiomycosis. fungal growth within host cells has been documented by light and transmission electron microscopy; however, entry of the fungus into host cells has not. our objective was to document how bd enters host cells in the wood frog lithobates sylvaticus, a species at high mortality risk for chytridiomycosi ...201222968788
prevalence of batrachochytrium dendrobatidis infection is extremely low in direct-developing australian microhylids.the emerging infectious disease chytridiomycosis has been implicated in declines and disappearances of amphibian populations around the world. however, susceptibility to infection and the extent of pathological effects of infection vary among hosts, and species with life histories that include parental care of direct-developing terrestrial eggs may tend to be less susceptible. we examined samples from a total of 595 individuals of 9 species of direct-developing australian frogs in the family mic ...201222968787
hybrid advantage in skin peptide immune defenses of water frogs (pelophylax esculentus) at risk from emerging pathogens.heterogeneity in immune defense effectors can benefit hosts encountering a variety of parasites and pathogens. antimicrobial peptides (amps) are a diverse set of immune defense effectors in many amphibians, and are secreted from dermal granular glands to protect the skin from infection. over 50 different skin peptides have been reported from the european water frog hybridogenic complex (pelophylax esculentus complex), consisting of the hybrid p. esculentus, and the parent species pelophylax less ...201222940461
getting under—and through—the skin: ecological genomics of chytridiomycosis infection in frogs.amphibian species around the world are currently becoming endangered or lost at a rate that outstrips other vertebrates—victims of a combination of habitat loss, climate change and susceptibility to emerging infectious disease (stuart et al. 2004). one of the most devastating such diseases is caused by the chytrid fungus batrachochytrium dendrobatidis (bd), which infects hundreds of amphibian species on multiple continents. while bd itself has been characterized for some time, we still know litt ...201222916344
synergistic inhibition of the lethal fungal pathogen batrachochytrium dendrobatidis: the combined effect of symbiotic bacterial metabolites and antimicrobial peptides of the frog rana muscosa.a powerful mechanism for protection against disease in animals is synergy between metabolites present in the natural microbiota of the host and antimicrobial peptides (amps) produced by the host. we studied this method of protection in amphibians in regard to the lethal disease chytridiomycosis, which is caused by batrachochytrium dendrobatidis (bd). in this study, we show that the amps of rana muscosa, as well as the metabolite 2,4-diacetylphloroglucinol (2,4-dapg) from pseudomonas fluorescens, ...201222914957
unlikely remedy: fungicide clears infection from pathogenic fungus in larval southern leopard frogs (lithobates sphenocephalus).amphibians are often exposed to a wide variety of perturbations. two of these, pesticides and pathogens, are linked to declines in both amphibian health and population viability. many studies have examined the separate effects of such perturbations; however, few have examined the effects of simultaneous exposure of both to amphibians. in this study, we exposed larval southern leopard frog tadpoles (lithobates sphenocephalus) to the chytrid fungus batrachochytrium dendrobatidis and the fungicide ...201222912890
germ tube mediated invasion of batrachochytrium dendrobatidis in amphibian skin is host dependent.batrachochytrium dendrobatidis (bd) is the causative agent of chytridiomycosis, a fungal skin disease in amphibians and driver of worldwide amphibian declines.we focussed on the early stages of infection by bd in 3 amphibian species with a differential susceptibility to chytridiomycosis. skin explants of alytes muletensis, litoria caerulea and xenopus leavis were exposed to bd in an ussing chamber for 3 to 5 days. early interactions of bd with amphibian skin were observed using light microscopy ...201222911798
batrachochytrium dendrobatidis zoospore secretions rapidly disturb intercellular junctions in frog skin.global amphibian declines are in part driven by the chytrid fungus batrachochytrium dendrobatidis, causing superficial dermatomycosis with epidermal hyperplasia and hyperkeratosis in infected amphibians. the susceptibility to chytridiomycosis and the severity of epidermal lesions in amphibians with chytridiomycosis are not consistent across species or even among individuals. severe infections cause death of the animal most likely through disturbance of ion homeostasis. the mechanism by which thi ...201222903040
novel, panzootic and hybrid genotypes of amphibian chytridiomycosis associated with the bullfrog trade.global amphibian declines are linked with the presence of specific, highly virulent genotypes of the emerging fungal disease chytridiomycosis caused by batrachochytrium dendrobatidis (bd) known as the global panzootic lineage (bd-gpl). the global trade in amphibians for human consumption is suspected to have facilitated emergence of the disease, but evidence to support this is largely lacking. here, we investigated the role the lithobates catesbeianus (north american bullfrog) trade in spreading ...201222857789
treatment of chytridiomycosis with reduced-dose itraconazole.effective treatment methods to eliminate infection with batrachochytrium dendrobatidis (bd) are required for development of sustainable captive survival assurance populations of amphibians and to reduce the risk of introducing bd to new locations as part of amphibian trade or reintroduction programs. treatment with itraconazole baths at 100 mg l-1 is commonly used in captive amphibians, but side effects are observed in some amphibian species and life stages. naturally occurring outbreaks of chyt ...201222832723
selecting for tolerance against pathogens and herbivores to enhance success of reintroduction and translocation.some species have insufficient defenses against climate change, emerging infectious diseases, and non-native species because they have not been exposed to these factors over their evolutionary history, and this can decrease their likelihood of persistence. captive breeding programs are sometimes used to reintroduce individuals back into the wild; however, successful captive breeding and reintroduction can be difficult because species or populations often cannot coexist with non-native pathogens ...201222809350
chloramphenicol with fluid and electrolyte therapy cures terminally ill green tree frogs (litoria caerulea) with chytridiomycosis.terminal changes in frogs infected with the amphibian fungal pathogen batrachochytrium dendrobatidis (bd) include epidermal degeneration leading to inhibited epidermal electrolyte transport, systemic electrolyte disturbances, and asystolic cardiac arrest. there are few reports of successful treatment of chytridiomycosis and none that include curing amphibians with severe disease. three terminally ill green tree frogs (litoria caerulea) with heavy bd infections were cured using a combination of c ...201222779237
widespread co-occurrence of virulent pathogens within california amphibian communities.the chytrid fungus batrachochytrium dendrobatidis, ranaviruses, and trematodes (ribeiroia ondatrae and echinostomes) are highly virulent pathogens known to infect amphibians, yet the extent to which they co-occur within amphibian communities remains poorly understood. using field surveillance of 85 wetlands in the east bay region of california, usa, we found that 68% of wetlands had ≥2 pathogens and 36% had ≥3 pathogens. wetlands with high pathogen species richness also tended to cluster spatial ...201222766887
road-killed common toads (bufo bufo) in flanders (belgium) reveal low prevalence of ranaviruses and batrachochytrium dendrobatidis. 201222740561
transmission of batrachochytrium dendrobatidis to wood frogs (lithobates sylvaticus) via a bullfrog (l. catesbeianus) vector.chytridiomycosis, an emerging infectious disease caused by the chytrid fungus batrachochytrium dendrobatidis, threatens anuran populations worldwide. effects of b. dendrobatidis on frog species are variable. some species typically develop nonlethal infections and may function as carriers; others typically develop lethal infections that can lead to population declines. nonlethal infections in the bullfrog (lithobates catesbeianus) are well-documented. in contrast, recently metamorphosed wood frog ...201222740523
prevalence of infection by batrachochytrium dendrobatidis and ranavirus in eastern hellbenders (cryptobranchus alleganiensis alleganiensis) in eastern tennessee.hellbenders (n=97) were collected from the little and hiwassee rivers in eastern tennessee, usa, during 2009 and 2010. location and morphometrics for each animal were recorded, and nonlethal tissue samples were collected to estimate the prevalence of infection with batrachochytrium dendrobatidis (bd) and ranavirus in each watershed and year. real-time polymerase chain reaction was performed on skin swabs for bd and on tail clips for ranaviruses. overall prevalences of dna of bd, ranavirus, and c ...201222740521
species-specific chitin-binding module 18 expansion in the amphibian pathogen batrachochytrium dendrobatidis.batrachochytrium dendrobatidis is the causative agent of chytridiomycosis, which is considered one of the driving forces behind the worldwide decline in populations of amphibians. as a member of the phylum chytridiomycota, b. dendrobatidis has diverged significantly to emerge as the only pathogen of adult vertebrates. such shifts in lifestyle are generally accompanied by various degrees of genomic modifications, yet neither its mode of pathogenicity nor any factors associated with it have ever b ...201222718849
controlling wildlife fungal disease spread: in vitro efficacy of disinfectants against batrachochytrium dendrobatidis and mucor amphibiorum.chytridiomycosis in amphibians, and mucormycosis in the platypus ornithorhynchus anatinus and amphibians, are serious fungal diseases affecting these aquatic taxa. in tasmania, australia, the fungi that cause these diseases overlap in range along with phytophthora cinnamomi (pc), an invasive fungal plant pathogen. to identify disinfectants that may be useful to reduce anthropogenic spread of these fungi to uninfected wilderness areas, for example by bush walkers and forestry or fire-fighting ope ...201222691980
field and laboratory studies of the susceptibility of the green treefrog (hyla cinerea) to batrachochytrium dendrobatidis infection.amphibians worldwide are experiencing devastating declines, some of which are due to the amphibian chytrid fungus (batrachochytrium dendrobatidis, bd). populations in the southeastern united states, however, have not been noticeably affected by the pathogen. the green treefrog (hyla cinerea) is abundant and widespread in the southeastern united states, but has not been documented to harbor bd infection. this study examined the susceptibility of h. cinerea to two strains of bd in the lab and the ...201222685572
genetic erosion in wild populations makes resistance to a pathogen more costly.populations that have suffered from genetic erosion are expected to exhibit reduced average trait values or decreased variation in adaptive traits when experiencing periodic or emergent stressors such as infectious disease. genetic erosion may consequentially modify the ability of a potential host population to cope with infectious disease emergence. we experimentally investigate this relationship between genetic variability and host response to exposure to an infectious agent both in terms of s ...201222671558
bd on the beach: high prevalence of batrachochytrium dendrobatidis in the lowland forests of gorgona island (colombia, south america).the amphibian chytrid fungus, batrachochytrium dendrobatidis, bd, has been implicated in the decimation and extinction of many amphibian populations worldwide, especially at mid and high elevations. recent studies have demonstrated the presence of the pathogen in the lowlands from australia and central america. we extend here its elevational range by demonstrating its presence at the sea level, in the lowland forests of gorgona island, off the pacific coast of colombia. we conducted two field su ...201222669408
sodium chloride inhibits the growth and infective capacity of the amphibian chytrid fungus and increases host survival rates.the amphibian chytrid fungus batrachochytrium dendrobatidis is a recently emerged pathogen that causes the infectious disease chytridiomycosis and has been implicated as a contributing factor in the global amphibian decline. since its discovery, research has been focused on developing various methods of mitigating the impact of chytridiomycosis on amphibian hosts but little attention has been given to the role of antifungal agents that could be added to the host's environment. sodium chloride is ...201222590639
magnetic capture hybridization of batrachochytrium dendrobatidis genomic dna.we hybridized biotinylated probes that anneal at multiple locations throughout the batrachochytrium dendrobatidis (bd) genome to selectively capture bd genomic dna (gdna) by binding the probe-gdna complex to streptavidin coated magnetic beads. we then whole genome amplified the captured gdna. this method extends the usefulness of field-collected swabs for downstream pcr-based genomic applications.201222579582
pathophysiology in mountain yellow-legged frogs (rana muscosa) during a chytridiomycosis outbreak.the disease chytridiomycosis is responsible for declines and extirpations of amphibians worldwide. chytridiomycosis is caused by a fungal pathogen (batrachochytrium dendrobatidis) that infects amphibian skin. although we have a basic understanding of the pathophysiology from laboratory experiments, many mechanistic details remain unresolved and it is unknown if disease development is similar in wild amphibian populations. to gain a better understanding of chytridiomycosis pathophysiology in wild ...201222558145
eradication of the chytrid fungus batrachochytrium dendrobatidis in the japanese giant salamander andrias japonicus.the purpose of this study was to establish a method for eradicating a chytrid fungus (batrachochytrium dendrobatidis; bd) from the japanese giant salamander andrias japonicus. the emerging agent (bd) has a high rate of detection in this endangered amphibian species, which is designated as a special natural monument in japan. four japanese giant salamanders with bd confirmed by pcr assay were bathed in 0.01% itraconazole for 5 min d-1 over 10 successive days. pcr assays were conducted prior to tr ...201222535874
effects of herbicides and the chytrid fungus batrachochytrium dendrobatidis on the health of post-metamorphic northern leopard frogs (lithobates pipiens).effects of exposure to contaminants such as pesticides along with exposure to pathogens have been listed as two major contributors to the global crisis of declining amphibian populations. these two factors have also been linked in explanations of the causes of these population declines. we conducted a combined exposure experiment to test the hypothesis that exposure to two agricultural herbicides would increase the susceptibility of post-metamorphic northern leopard frogs (lithobates pipiens) to ...201222520452
waterfowl: potential environmental reservoirs of the chytrid fungus batrachochytrium dendrobatidis.infections with batrachochytrium dendrobatidis (b. dendrobatidis), the causal agent of chytridiomycosis, have been shown to play an important role in the decline of amphibians worldwide. spread of the fungus is poorly understood. bird movement might possibly contribute to the spread of b. dendrobatidis in the environment. therefore, 397 wild geese in belgium were screened for presence of b. dendrobatidis on their toes using real-time quantitative pcr (qpcr). in addition, chemotaxis towards, adhe ...201222514705
populations of a susceptible amphibian species can grow despite the presence of a pathogenic chytrid fungus.disease can be an important driver of host population dynamics and epizootics can cause severe host population declines. batrachochytrium dendrobatidis (bd), the pathogen causing amphibian chytridiomycosis, may occur epizootically or enzootically and can harm amphibian populations in many ways. while effects of bd epizootics are well documented, the effects of enzootic bd have rarely been described. we used a state-space model that accounts for observation error to test whether population trends ...201222496836
batrachochytrium dendrobatidis in amphibians confiscated from illegal wildlife trade and used in an ex situ breeding program in brazil.this paper describes an outbreak of chytridiomycosis affecting a group of dendrobates tinctorius, a neotropical anuran species, confiscated from the illegal wildlife trade and housed in a private zoo in brazil as part of an ex situ breeding program. we examined histological sections of the skin of 30 d. tinctorius and 20 adelphobates galactonotus individuals. twenty d. tinctorius (66.7%) and none of the a. galactonotus were positive for batrachochytrium dendrobatidis (bd). multiple development s ...201222436465
batrachochytrium dendrobatidis infection of amphibians in the doñana national park, spain.amphibian chytridiomycosis, caused by infection with the non-hyphal, zoosporic chytrid fungus batrachochytrium dendrobatidis (bd), is an emerging infectious disease recognised as a cause of recent amphibian population declines and extinctions worldwide. the doñana national park (dnp) is located in southwestern spain, a country with widespread bd infection. this protected area has a great diversity of aquatic habitats that constitute important breeding habitats for 11 native amphibian species. we ...201222436459
qualitative risk analysis of introducing batrachochytrium dendrobatidis to the uk through the importation of live amphibians.the international amphibian trade is implicated in the emergence and spread of the amphibian fungal disease chytridiomycosis, which has resulted in amphibian declines and extinctions globally. the establishment of the causal pathogen, batrachochytrium dendrobatidis (bd), in the uk could negatively affect the survival of native amphibian populations. in recognition of the ongoing threat that it poses to amphibians, bd was recently included in the world organisation for animal health aquatic anima ...201222436458
a reservoir species for the emerging amphibian pathogen batrachochytrium dendrobatidis thrives in a landscape decimated by disease.chytridiomycosis, a disease caused by the fungal pathogen batrachochytrium dendrobatidis (bd), is driving amphibian declines and extinctions in protected areas globally. the introduction of invasive reservoir species has been implicated in the spread of bd but does not explain the appearance of the pathogen in remote protected areas. in the high elevation (>1500 m) sierra nevada of california, the native pacific chorus frog, pseudacris regilla, appears unaffected by chytridiomycosis while sympat ...201222428071
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