| rapid extirpation of a north american frog coincides with an increase in fungal pathogen prevalence: historical analysis and implications for reintroduction. | as extinctions continue across the globe, conservation biologists are turning to species reintroduction programs as one optimistic tool for addressing the biodiversity crisis. for repatriation to become a viable strategy, fundamental prerequisites include determining the causes of declines and assessing whether the causes persist in the environment. invasive species-especially pathogens-are an increasingly significant factor contributing to biodiversity loss. we hypothesized that batrachochytriu ... | 2017 | 29238549 |
| using environmental dna for early detection of amphibian chytrid fungus batrachochytrium dendrobatidis prior to a ranid die-off. | amphibian chytridiomycosis caused by the fungus batrachochytrium dendrobatidis (bd) is an emerging infectious disease that has been associated with mass mortality and extinctions of amphibians worldwide. environmental dna (edna) techniques have been used to detect the presence of bd in the environment, but not to detect bd prior to an amphibian die-off. we collected edna using filtered water samples from 13 lakes across sequoia kings canyon national park. seven of those sites had populations of ... | 2017 | 29256431 |
| 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 ... | 2012 | 22558145 |
| 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 ... | 2012 | 22916344 |
| mountain yellow-legged frogs (rana muscosa) did not produce detectable antibodies in immunization experiments with batrachochytrium dendrobatidis. | chytridiomycosis is a devastating infectious disease of amphibians caused by the fungal pathogen batrachochytrium dendrobatidis (bd). a growing number of studies have examined the role of amphibian adaptive immunity in response to this pathogen, with varying degrees of immune activation reported. here we present immunologic data for the mountain yellow-legged frog, rana muscosa, and the sierra nevada yellow-legged frog, rana sierrae, which are two endangered and ecologically important species ex ... | 2016 | 26540180 |
| citizen scientists monitor a deadly fungus threatening amphibian communities in northern coastal california, usa. | ecoclub youth and supervising family members conducted citizen science to assess regional prevalence and distribution of batrachochytrium dendrobatidis (bd) among amphibians at humboldt bay national wildlife refuge (refuge) and redwood national and state parks (parks), humboldt county, california, us, may 2013 through december 2014. using quantitative real-time pcr, 26 (17%) of 155 samples were positive for bd. positive samples occurred in four frog and toad species: foothill yellow-legged frog ... | 2016 | 27195681 |
| integral projection models for host-parasite systems with an application to amphibian chytrid fungus. | host parasite models are typically constructed under either a microparasite or macroparasite paradigm. however, this has long been recognized as a false dichotomy because many infectious disease agents, including most fungal pathogens, have attributes of both microparasites and macroparasites.we illustrate how integral projection models (ipm)s provide a novel, elegant modeling framework to represent both types of pathogens. we build a simple host-parasite ipm that tracks both the number of susce ... | 2016 | 28239442 |
| 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 ... | 2011 | 21295070 |
| cutaneous bacteria of the redback salamander prevent morbidity associated with a lethal disease. | chytridiomycosis, caused by the fungal pathogen batrachochytrium dendrobatidis (bd), is an infectious disease that causes population declines of many amphibians. cutaneous bacteria isolated from redback salamanders, plethodon cinereus, and mountain yellow-legged frogs, rana muscosa, inhibit the growth of bd in vitro. in this study, the bacterial community present on the skin of p. cinereus individuals was investigated to determine if it provides protection to salamanders from the lethal and sub- ... | 2010 | 20532032 |
| dynamics of an emerging disease drive large-scale amphibian population extinctions. | epidemiological theory generally suggests that pathogens will not cause host extinctions because the pathogen should fade out when the host population is driven below some threshold density. an emerging infectious disease, chytridiomycosis, caused by the fungal pathogen batrachochytrium dendrobatidis (bd) is directly linked to the recent extinction or serious decline of hundreds of amphibian species. despite continued spread of this pathogen into uninfected areas, the dynamics of the host-pathog ... | 2010 | 20457913 |
| immunization is ineffective at preventing infection and mortality due to the amphibian chytrid fungus batrachochytrium dendrobatidis. | the fungal pathogen batrachochytrium dendrobatidis (bd), the causative agent of chytridiomycosis, has been implicated in amphibian declines worldwide. it has been hypothesized that low inherent immunogenicity in bd may be related to the high rates of morbidity and mortality that are associated with bd-infected anuran populations. to test this idea, juvenile rana muscosa (mountain yellow-legged frogs) were immunized with adjuvants in combination with a formalin-killed bd culture to determine if i ... | 2010 | 20090019 |
| effect of temperature on host response to batrachochytrium dendrobatidis infection in the mountain yellow-legged frog (rana muscosa). | the pathogenic chytrid fungus batrachochytrium dendrobatidis, which causes the disease chytridiomycosis, has been implicated in declines of amphibian populations throughout the world, including declines and extinctions of local populations of mountain yellow-legged frogs, rana muscosa, in the california sierra nevada. previous studies have shown b. dendrobatidis achieves its maximum growth rate in culture in the temperature range of 17-25 c, and exposure to very high temperatures can clear frogs ... | 2008 | 18689660 |
| quantifying the disease transmission function: effects of density on batrachochytrium dendrobatidis transmission in the mountain yellow-legged frog rana muscosa. | 1. chytridiomycosis is an emerging infectious disease of amphibians, caused by the fungal pathogen batrachochytrium dendrobatidis, which has been implicated recently in population declines and possible extinctions throughout the world. 2. the transmission rate of this pathogen was quantified in the mountain yellow-legged frog rana muscosa through laboratory and field experiments, and a maximum likelihood approach was used to determine the form of the transmission function that was best supported ... | 2007 | 17584377 |
| effects of chytrid and carbaryl exposure on survival, growth and skin peptide defenses in foothill yellow-legged frogs. | environmental contaminants and disease may synergistically contribute to amphibian population declines. sub-lethal levels of contaminants can suppress amphibian immune defenses and, thereby, may facilitate disease outbreaks. we conducted laboratory experiments on newly metamorphosed foothill yellow-legged frogs (rana boylii) to determine whether sublethal exposure to the pesticide carbaryl would increase susceptibility to the pathogenic chytrid fungus batrachochytrium dendrobatidis that is widel ... | 2007 | 17396672 |
| removal of nonnative fish results in population expansion of a declining amphibian (mountain yellow-legged frog, rana muscosa). | the mountain yellow-legged frog (rana muscosa) was once a common inhabitant of the sierra nevada (california, usa), but has declined precipitously during the past century due in part to the introduction of nonnative fish into naturally fishless habitats. the objectives of the current study were to describe (1) the effect of fish removal from three lakes (located in two watersheds) on the small, remnant r. muscosa populations inhabiting those lakes, and (2) the initial development of metapopulati ... | 2007 | 17396156 |
| emerging infectious disease as a proximate cause of amphibian mass mortality. | a newly discovered infectious disease of amphibians, chytridiomycosis, caused by the fungal pathogen batrachochytrium dendrobatidis, is implicated in population declines and possible extinctions throughout the world. the purpose of our study was to examine the effects of b. dendrobatidis on the mountain yellow-legged frog (rana muscosa) in the sierra nevada of california (usa). we (1) quantified the prevalence and incidence of b. dendrobatidis through repeat surveys of several hundred r. muscosa ... | 2006 | 16922318 |
| antimicrobial peptide defenses of the mountain yellow-legged frog (rana muscosa). | the mountain yellow-legged frog (rana muscosa) inhabits high elevation lakes in california that are largely undisturbed by human activities. in spite of this habitation in remote sites, populations continue to decline. although predation by non-native fish is one cause for declines, some isolated populations in fishless lakes are suffering new declines. one possible cause of the current wave of declines is the introduction of the pathogenic chytrid fungus (batrachochytrium dendrobatidis) which i ... | 2006 | 16330099 |
| transmission of batrachochytrium dendrobatidis within and between amphibian life stages. | chytridiomycosis is an emerging infectious disease caused by the chytrid fungus batrachochytrium dendrobatidis, which has been implicated in amphibian declines worldwide. the mountain yellow-legged frog rana muscosa is a declining amphibian species that can be infected by b. dendrobatidis; however, transmission between conspecifics has not been documented. here, we present experimental evidence that r. muscosa tadpoles can be infected by fungal zoospores and that they can transmit infection to e ... | 2004 | 15584413 |