Exciting new discovery for the chytrid mystery

2018 ◽  
Vol 182 (8) ◽  
pp. 212-213
Keyword(s):  
Infectious Disease ◽  
Fungal Pathogen ◽  
Batrachochytrium Dendrobatidis ◽  
Emerging Infectious Disease ◽  
Amphibian Species ◽  
New Research ◽  
Shed Light ◽  
New Discovery

The emerging infectious disease chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis, is thought to affect over 500 amphibian species worldwide. But, as Georgina Mills explains, new research has now shed light on what could make some individuals more susceptible

scholarly journals Epidemic and endemic pathogen dynamics correspond to distinct host population microbiomes at a landscape scale

2017 ◽  
Vol 284 (1857) ◽  
pp. 20170944 ◽  
Author(s):  
Andrea J. Jani ◽  
Roland A. Knapp ◽  
Cheryl J. Briggs
Keyword(s):  
Infectious Disease ◽  
Fungal Pathogen ◽  
Batrachochytrium Dendrobatidis ◽  
Infection Intensity ◽  
Host Population ◽  
Symbiotic Bacteria ◽  
Skin Microbiome ◽  
Pathogen Infection ◽  
Microbiome Composition ◽  
Pathogen Invasion

Infectious diseases have serious impacts on human and wildlife populations, but the effects of a disease can vary, even among individuals or populations of the same host species. Identifying the reasons for this variation is key to understanding disease dynamics and mitigating infectious disease impacts, but disentangling cause and correlation during natural outbreaks is extremely challenging. This study aims to understand associations between symbiotic bacterial communities and an infectious disease, and examines multiple host populations before or after pathogen invasion to infer likely causal links. The results show that symbiotic bacteria are linked to fundamentally different outcomes of pathogen infection: host–pathogen coexistence (endemic infection) or host population extirpation (epidemic infection). Diversity and composition of skin-associated bacteria differed between populations of the frog, Rana sierrae , that coexist with or were extirpated by the fungal pathogen, Batrachochytrium dendrobatidis (Bd). Data from multiple populations sampled before or after pathogen invasion were used to infer cause and effect in the relationship between the fungal pathogen and symbiotic bacteria. Among host populations, variation in the composition of the skin microbiome was most strongly predicted by pathogen infection severity, even in analyses where the outcome of infection did not vary. This result suggests that pathogen infection shapes variation in the skin microbiome across host populations that coexist with or are driven to extirpation by the pathogen. By contrast, microbiome richness was largely unaffected by pathogen infection intensity, but was strongly predicted by geographical region of the host population, indicating the importance of environmental or host genetic factors in shaping microbiome richness. Thus, while both richness and composition of the microbiome differed between endemic and epidemic host populations, the underlying causes are most likely different: pathogen infection appears to shape microbiome composition, while microbiome richness was less sensitive to pathogen-induced disturbance. Because higher richness was correlated with host persistence in the presence of Bd, and richness appeared relatively stable to Bd infection, microbiome richness may contribute to disease resistance, although the latter remains to be directly tested.

scholarly journals Antifungal Bacteria on Woodland Salamander Skin Exhibit High Taxonomic Diversity and Geographic Variability

2017 ◽  
Vol 83 (9) ◽  
Author(s):  
Carly R. Muletz-Wolz ◽  
Graziella V. DiRenzo ◽  
Stephanie A. Yarwood ◽  
Evan H. Campbell Grant ◽  
Robert C. Fleischer ◽  
...  
Keyword(s):  
Fungal Pathogen ◽  
Batrachochytrium Dendrobatidis ◽  
Bacterial Species ◽  
Rrna Gene ◽  
Amphibian Skin ◽  
Amphibian Species ◽  
Protective Function ◽  
Content Type ◽  
Skin Bacteria ◽  
Salamander Species

ABSTRACT Diverse bacteria inhabit amphibian skin; some of those bacteria inhibit growth of the fungal pathogen Batrachochytrium dendrobatidis. Yet there has been no systematic survey of anti-B. dendrobatidis bacteria across localities, species, and elevations. This is important given geographic and taxonomic variations in amphibian susceptibility to B. dendrobatidis. Our collection sites were at locations within the Appalachian Mountains where previous sampling had indicated low B. dendrobatidis prevalence. We determined the numbers and identities of anti-B. dendrobatidis bacteria on 61 Plethodon salamanders (37 P. cinereus, 15 P. glutinosus, 9 P. cylindraceus) via culturing methods and 16S rRNA gene sequencing. We sampled co-occurring species at three localities and sampled P. cinereus along an elevational gradient (700 to 1,000 meters above sea level [masl]) at one locality. We identified 50 anti-B. dendrobatidis bacterial operational taxonomic units (OTUs) and found that the degree of B. dendrobatidis inhibition was not correlated with relatedness. Five anti-B. dendrobatidis bacterial strains occurred on multiple amphibian species at multiple localities, but none were shared among all species and localities. The prevalence of anti-B. dendrobatidis bacteria was higher at Shenandoah National Park (NP), VA, with 96% (25/26) of salamanders hosting at least one anti-B. dendrobatidis bacterial species compared to 50% (7/14) at Catoctin Mountain Park (MP), MD, and 38% (8/21) at Mt. Rogers National Recreation Area (NRA), VA. At the individual level, salamanders at Shenandoah NP had more anti-B. dendrobatidis bacteria per individual (μ = 3.3) than those at Catoctin MP (μ = 0.8) and at Mt. Rogers NRA (μ = 0.4). All salamanders tested negative for B. dendrobatidis. Anti-B. dendrobatidis bacterial species are diverse in central Appalachian Plethodon salamanders, and their distribution varied geographically. The antifungal bacterial species that we identified may play a protective role for these salamanders. IMPORTANCE Amphibians harbor skin bacteria that can kill an amphibian fungal pathogen, Batrachochytrium dendrobatidis. Some amphibians die from B. dendrobatidis infection, whereas others do not. The bacteria that can kill B. dendrobatidis, called anti-B. dendrobatidis bacteria, are thought to influence the B. dendrobatidis infection outcome for the amphibian. Yet how anti-B. dendrobatidis bacterial species vary among amphibian species and populations is unknown. We determined the distribution of anti-B. dendrobatidis bacterial species among three salamander species (n = 61) sampled at three localities. We identified 50 unique anti-B. dendrobatidis bacterial species and found that all of the tested salamanders were negative for B. dendrobatidis. Five anti-B. dendrobatidis bacterial species were commonly detected, suggesting a stable, functional association with these salamanders. The number of anti-B. dendrobatidis bacteria per individual varied among localities but not among co-occurring salamander species, demonstrating that environment is more influential than host factors in structuring the anti-B. dendrobatidis bacterial community. These anti-B. dendrobatidis bacteria may serve a protective function for their salamander hosts.

scholarly journals Amphibian species vary in their learned avoidance response to the deadly fungal pathogen Batrachochytrium dendrobatidis

2021 ◽  
Author(s):  
Taegan A. McMahon ◽  
Megan N. Hill ◽  
Garrett C. Lentz ◽  
Electra F. Scott ◽  
Nadia F. Tenouri ◽  
...  
Keyword(s):  
Avoidance Response ◽  
Fungal Pathogen ◽  
Batrachochytrium Dendrobatidis ◽  
Amphibian Species

scholarly journals Prevalence of the fungal pathogen Batrachochytrium dendrobatidis in amphibians of Costa Rica predated first-known epizootic

2018 ◽  
Author(s):  
Marina E. De León ◽  
Héctor Zumbado-Ulate ◽  
Adrián García-Rodríguez ◽  
Gilbert Alvarado ◽  
Hasan Sulaeman ◽  
...  
Keyword(s):  
Costa Rica ◽  
Fungal Pathogen ◽  
Batrachochytrium Dendrobatidis ◽  
Emerging Infectious Diseases ◽  
Infection Prevalence ◽  
Pcr Assay ◽  
Local Data ◽  
Amphibian Species ◽  
Genetic Lineages ◽  
Quantitative Pcr Assay

AbstractEmerging infectious diseases are a growing threat to biodiversity worldwide. Outbreaks of the infectious disease chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), have caused the decline and extinction of numerous amphibian species. In Costa Rica, a major decline event occurred in 1987, more than two decades before this pathogen was discovered. The loss of many species in Costa Rica is assumed to be due to Bd-epizootics, but there are few studies that provide data from amphibians in the time leading up to the proposed epizootics. In this study, we provide new data on Bd infection rates of amphibians collected throughout Costa Rica, in the decades prior to the epizootics. We used a quantitative PCR assay to test for Bd infection in 1016 specimens collected throughout Costa Rica. We found Bd-infected hosts collected as early as 1964, and a infection prevalence average per decade of just 4%. The infection prevalence remained relatively low and geographically constrained until the 1980s when epizootics are hypothesized to have occurred. After that time, infection prevalence increased three-fold and Bd-infected hosts we collected throughout the entire country. Our results, suggest that Bd may either have invaded Costa Rica earlier than previously known, and spread more slowly than previously reported, or that an endemic lineage of the pathogen may exists. To help visualize areas where future studies should take place, we provide a Bd habitat suitability model trained with local data. Studies that provide information on genetic lineages of Bd are needed to determine whether an endemic lineage of Bd or the Global Panzootic Lineage (identified from mass die off sites globally) was present in Costa Rica and responsible for the epizootics that caused amphibian communities to collapse.

scholarly journals Infectious disease threats to amphibian conservation

2018 ◽  
Vol 27 (Supplement) ◽  
pp. 81-90
Author(s):  
A.A. Cunningham
Keyword(s):  
Infectious Disease ◽  
Batrachochytrium Dendrobatidis ◽  
Biodiversity Loss ◽  
Amphibian Conservation ◽  
Disease Spread ◽  
Population Declines ◽  
Amphibian Species ◽  
Late 20Th Century ◽  
Amphibian Population ◽  
In The Wild

The unexplained decline of amphibian populations across the world was first recognised in the late 20th century. When investigated, most of these “enigmatic” declines have been shown to be due to one of two types of infectious disease: ranavirosis caused by infection with FV3-like ranavirus or with common midwife toad virus, or chytridiomycosis caused by infection with Batrachochytrium dendrobatidis or B. salamandrivorans. In all cases examined, infection has been via the human-mediated introduction of the pathogen to a species or population in which it has not naturally co-evolved. While ranaviruses and B. salamandrivorans have caused regionally localised amphibian population declines in Europe, the chytrid fungus, B. dendrobatidis, has caused catastrophic multi-species amphibian population declines and species extinctions globally. These diseases have already caused the loss of amphibian biodiversity, and over 40% of known amphibian species are threatened with extinction. If this biodiversity loss is to be halted, it is imperative that regulations are put in place – and enforced – to prevent the spread of known and yet-to-be discovered amphibian pathogens. Also, it is incumbent on those who keep or study amphibians to take measures to minimise the risk of disease spread, including from captive animals to those in the wild.

7. Batrachochytrium dendrobatidis

2015 ◽  
pp. 82-96
Author(s):  
Marta L. Wayne ◽  
Benjamin M. Bolker
Keyword(s):  
Natural History ◽  
Central America ◽  
Fungal Pathogen ◽  
Batrachochytrium Dendrobatidis ◽  
Emerging Diseases ◽  
The Novel ◽  
Emerging Pathogen ◽  
Amphibian Species ◽  
History Of

Batrachochytrium dendrobatidis (Bd) is a fungal pathogen that infects many different amphibian species, driving some of them to extinction. ‘Batrachochytrium dendrobatidis’ considers the physiology and natural history of this emerging pathogen; its discovery in the late 1990s in Australia and Central America; and the concepts and strategies used to try to determine its origins. Has it arrived relatively recently in the communities it was destroying, or did it lie dormant in those communities for millennia before suddenly beginning to cause harm? The debate between the novel pathogen hypothesis and the endemic pathogen hypothesis, versions of which apply to most emerging diseases of wildlife, is ongoing.

scholarly journals The Effect of Aquatic and Terrestrial Environmental Factors on the Interaction Between Grand Teton Boreal Toads and a Lethal Fungal Pathogen

2008 ◽  
Vol 31 ◽  
pp. 125-131
Author(s):  
Peter Murphy ◽  
Sophie St-Hilaire ◽  
Charles Peterson
Keyword(s):  
Fungal Pathogen ◽  
Batrachochytrium Dendrobatidis ◽  
Chytrid Fungus ◽  
Population Declines ◽  
Amphibian Skin ◽  
Amphibian Species ◽  
American Bullfrog ◽  
The North ◽  
S 100 ◽  
Boreal Toads

Batrachochytrium dendrobatidis (Bd), the chytrid fungus which infects keratinized amphibian skin and causes the lethal disease chytridiomycosis, has been linked to population declines and extinctions worldwide (Lips et al. 2006). Amphibians infected with Bd may suffer a variety of outcomes. Individuals of some species have been killed by :S 100 Bd zoospores, while other species, such as the North American bullfrog Rana catesbiana, are highly resistant (Daszak et al. 2004). Within an amphibian species, populations may also respond differently to Bd, with some declining et al. remaining stable (Kriger and Hero 2006). Divergent outcomes among species and populations with respect to Bd may arise from at least three factors, or their interaction.

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