Publications
247 results found
Garner TWJ, Rowcliffe JM, Fisher MC, 2011, Climate change, chytridiomycosis or condition: an experimental test of amphibian survival, GLOBAL CHANGE BIOLOGY, Vol: 17, Pages: 667-675, ISSN: 1354-1013
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- Citations: 59
El Mouden EH, Slimani T, Donaire D, et al., 2011, First record of the chytrid fungus Batrachochytrium dendrobatidis in North Africa, Herpetological Review, Vol: 42, Pages: 71-75, ISSN: 0018-084X
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- Citations: 21
Xu J, Manosuthi W, Banerjee U, et al., 2011, Cryptococcosis in Asia, CRYPTOCOCCUS: FROM HUMAN PATHOGEN TO MODEL YEAST, Editors: Heitman, Kozel, KwonChung, Perfect, Casadevall, Publisher: AMER SOC MICROBIOLOGY, Pages: 287-297, ISBN: 978-1-55581-501-1
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- Citations: 8
Simwami SP, Khayhan K, Henk DA, et al., 2011, Low Diversity Cryptococcus neoformans Variety grubii Multilocus Sequence Types from Thailand Are Consistent with an Ancestral African Origin, Plos Pathog, Vol: 7, ISSN: 1553-7366
The global burden of HIV-associated cryptococcal meningitis is estimated at nearly one million cases per year, causing up to a third of all AIDS-related deaths. Molecular epidemiology constitutes the main methodology for understanding the factors underpinning the emergence of this understudied, yet increasingly important, group of pathogenic fungi. Cryptococcus species are notable in the degree that virulence differs amongst lineages, and highly-virulent emerging lineages are changing patterns of human disease both temporally and spatially. Cryptococcus neoformans variety grubii (Cng, serotype A) constitutes the most ubiquitous cause of cryptococcal meningitis worldwide, however patterns of molecular diversity are understudied across some regions experiencing significant burdens of disease. We compared 183 clinical and environmental isolates of Cng from one such region, Thailand, Southeast Asia, against a global MLST database of 77 Cng isolates. Population genetic analyses showed that Thailand isolates from 11 provinces were highly homogenous, consisting of the same genetic background (globally known as VNI) and exhibiting only ten nearly identical sequence types (STs), with three (STs 44, 45 and 46) dominating our sample. This population contains significantly less diversity when compared against the global population of Cng, specifically Africa. Genetic diversity in Cng was significantly subdivided at the continental level with nearly half (47%) of the global STs unique to a genetically diverse and recombining population in Botswana. These patterns of diversity, when combined with evidence from haplotypic networks and coalescent analyses of global populations, are highly suggestive of an expansion of the Cng VNI clade out of Africa, leading to a limited number of genotypes founding the Asian populations. Divergence time testing estimates the time to the most common ancestor between the African and Asian populations to be 6,920 years ago (95% HPD 122.96 - 27,177.76
Gladieux P, Byrnes EJ, Aguileta G, et al., 2011, Epidemiology and Evolution of Fungal Pathogens in Plants and Animals, GENETICS AND EVOLUTION OF INFECTIOUS DISEASES, Editors: Tibayrenc, Publisher: ELSEVIER SCIENCE BV, Pages: 59-132, ISBN: 978-0-12-384890-1
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- Citations: 25
Meece JK, Anderson JL, Fisher MC, et al., 2011, Population Genetic Structure of Clinical and Environmental Isolates of Blastomyces dermatitidis, Based on 27 Polymorphic Microsatellite Markers, Appl Environ Microb, Vol: 77, Pages: 5123-5131, ISSN: 0099-2240
Blastomyces dermatitidis, a thermally dimorphic fungus, is the etiologic agent of North American blastomycosis. Clinical presentation is varied, ranging from silent infections to fulminant respiratory disease and dissemination to skin and other sites. Exploration of the population genetic structure of B. dermatitidis would improve our knowledge regarding variation in virulence phenotypes, geographic distribution, and difference in host specificity. The objective of this study was to develop and test a panel of microsatellite markers to delineate the population genetic structure within a group of clinical and environmental isolates of B. dermatitidis. We developed 27 microsatellite markers and genotyped B. dermatitidis isolates from various hosts and environmental sources (n = 112). Assembly of a neighbor-joining tree of allele-sharing distance revealed two genetically distinct groups, separated by a deep node. Bayesian admixture analysis showed that two populations were statistically supported. Principal coordinate analysis also reinforced support for two genetic groups, with the primary axis explaining 61.41% of the genetic variability. Group 1 isolates average 1.8 alleles/locus, whereas group 2 isolates are highly polymorphic, averaging 8.2 alleles/locus. In this data set, alleles at three loci are unshared between the two groups and appear diagnostic. The mating type of individual isolates was determined by PCR. Both mating type-specific genes, the HMG and alpha-box domains, were represented in each of the genetic groups, with slightly more isolates having the HMG allele. One interpretation of this study is that the species currently designated B. dermatitidis includes a cryptic subspecies or perhaps a separate species.
Henk DA, Eagle CE, Brown K, et al., 2011, Speciation despite globally overlapping distributions in Penicillium chrysogenum: the population genetics of Alexander Fleming's lucky fungus, Mol Ecol, Vol: 20, Pages: 4288-4301, ISSN: 0962-1083
Eighty years ago, Alexander Fleming described the antibiotic effects of a fungus that had contaminated his bacterial culture, kick starting the antimicrobial revolution. The fungus was later ascribed to a putatively globally distributed asexual species, Penicillium chrysogenum. Recently, the species has been shown to be genetically diverse, and possess mating-type genes. Here, phylogenetic and population genetic analyses show that this apparently ubiquitous fungus is actually composed of at least two genetically distinct species with only slight differences detected in physiology. We found each species in air and dust samples collected in and around St Mary's Hospital where Fleming worked. Genotyping of 30 markers across the genome showed that preserved fungal material from Fleming's laboratory was nearly identical to derived strains currently in culture collections and in the same distinct species as a wild progenitor strain of current penicillin producing industrial strains rather than the type species P. chrysogenum. Global samples of the two most common species were found to possess mating-type genes in a near 1:1 ratio, and show evidence of recombination with little geographic population subdivision evident. However, no hybridization was detected between the species despite an estimated time of divergence of less than 1 MYA. Growth studies showed significant interspecific inhibition by P. chrysogenum of the other common species, suggesting that competition may facilitate species maintenance despite globally overlapping distributions. Results highlight under-recognized diversity even among the best-known fungal groups and the potential for speciation despite overlapping distribution.
Liang L, Cao CW, Wang WJ, et al., 2011, Common Reservoirs for Penicillium marneffei Infection in Humans and Rodents, China, Emerg Infect Dis, Vol: 17, Pages: 209-214, ISSN: 1080-6040
Human penicilliosis marneffei is an emerging infectious disease caused by the fungus Penicillium marneffei. High prevalence of infection among bamboo rats of the genera Rhizomys and Cannomys suggest that these rodents are a key facet of the P marneffei life cycle. We trapped bamboo rats during June 2004-July 2005 across Guangxi Province, China, and demonstrated 100% prevalence of infection. Multi locus genotypes show that P marneffei isolates from humans are similar to those infecting rats and are in some cases identical. Comparison of our dataset with genotypes recovered from sites across Southeast Asia shows that the overriding component of genetic structure in P marneffei is spatial, with humans containing a greater diversity of genotypes than rodents. Humans and bamboo rats are sampling an as-yet undiscovered common reservoir of infection, or bamboo rats are a vector for human infections by acting as amplifiers of infectious dispersal stages.
Rosenblum EB, Fisher MC, James TY, et al., 2010, A molecular perspective: biology of the emerging pathogen <i>Batrachochytrium dendrobatidis</i>, DISEASES OF AQUATIC ORGANISMS, Vol: 92, Pages: 131-147, ISSN: 0177-5103
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- Citations: 22
Cao WC, Liang L, Wang JW, et al., 2010, Shared genotype Penicillium marneffei infections in humans and rodents demonstrate common reservoirs of infection in China, JOURNAL OF DERMATOLOGY, Vol: 37, Pages: 94-94, ISSN: 0385-2407
Solis R, Lobos G, Walker SF, et al., 2010, Presence of Batrachochytrium dendrobatidis in feral populations of Xenopus laevis in Chile, BIOLOGICAL INVASIONS, Vol: 12, Pages: 1641-1646, ISSN: 1387-3547
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- Citations: 39
Walker SF, Bosch J, Gomez V, et al., 2010, Factors driving pathogenicity vs. prevalence of amphibian panzootic chytridiomycosis in Iberia, Ecol Lett, Vol: 13, Pages: 372-382, ISSN: 1461-023X
P>Amphibian chytridiomycosis is a disease caused by the fungus Batrachochytrium dendrobatidis (Bd). Whether Bd is a new emerging pathogen (the novel pathogen hypothesis; NPH) or whether environmental changes are exacerbating the host-pathogen dynamic (the endemic pathogen hypothesis; EPH) is debated. To disentangle these hypotheses we map the distribution of Bd and chytridiomycosis across the Iberian Peninsula centred on the first European outbreak site. We find that the infection-free state is the norm across both sample sites and individuals. To analyse this dataset, we use Bayesian zero-inflated binomial models to test whether environmental variables can account for heterogeneity in both the presence and prevalence of Bd, and heterogeneity in the occurrence of the disease, chytridiomycosis. We also search for signatures of Bd-spread within Iberia using genotyping. We show (1) no evidence for any relationship between the presence of Bd and environmental variables, (2) a weak relationship between environmental variables and the conditional prevalence of infection, (3) stage-dependent heterogeneity in the infection risk, (4) a strong association between altitude and chytridiomycosis, (5) multiple Iberian genotypes and (6) recent introduction and spread of a single genotype of Bd in the Pyrenees. We conclude that the NPH is consistent with the emergence of Bd in Iberia. However, epizootic forcing of infection is tied to location and shaped by both biotic and abiotic variables. Therefore, the population-level consequences of disease introduction are explained by EPH-like processes. This study demonstrates the power of combining surveillance and molecular data to ascertain the drivers of new emerging infections diseases.
Ribas L, Li MS, Doddington BJ, et al., 2009, Expression Profiling the Temperature-Dependent Amphibian Response to Infection by Batrachochytrium dendrobatidis, PLOS One, Vol: 4, ISSN: 1932-6203
Amphibians are experiencing a panzootic of unprecedented proportions caused by the emergence of Batrachochytrium dendrobatidis (Bd). However, all species are not equally at risk of infection, and risk is further modified by environmental variables, specifically temperature. In order to understand how, and when, hosts mount a response to Bd we analysed infection dynamics and patterns of gene expression in the model amphibian species Silurana (Xenopus) tropicalis. Mathematical modelling of infection dynamics demonstrate the existence of a temperature-dependent protective response that is largely independent of the intrinsic growth-rate of Bd. Using temporal expression-profiling by microarrays and qRT-PCR, we characterise this response in the main amphibian lymphoid tissue, the spleen. We demonstrate that clearance of Bd at the host-optimal temperature is not clearly associated with an adaptive immune response, but rather is correlated with the induction of components of host innate immunity including the expression of genes that are associated with the production of the antimicrobial skin peptide preprocareulein (PPCP) as well as inflammatory responses. We find that adaptive immunity appears to be lacking at host-optimal temperatures. This suggests that either Bd does not stimulate, or suppresses, adaptive immunity, or that trade-offs exist between innate and adaptive limbs of the amphibian immune system. At cold temperatures, S. tropicalis loses the ability to mount a PPCP-based innate response, and instead manifests a more pronounced inflammatory reaction that is characterised by the production of proteases and higher pathogen burdens. This study demonstrates the temperature-dependency of the amphibian response to infection by Bd and indicates the influence that changing climates may exert on the ectothermic host response to pathogens.
Fisher MC, 2009, Endemic and introduced haplotypes of <i>Batrachochytrium dendrobatidis</i> in Japanese amphibians: sink or source?, MOLECULAR ECOLOGY, Vol: 18, Pages: 4731-4733, ISSN: 0962-1083
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- Citations: 11
Fisher MC, 2009, Disease-driven declines in global amphibian biodiversity, Microbiology Today, Vol: 36, Pages: 208-211, ISSN: 1464-0570
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- Citations: 1
Rödder D, Kielgast J, Bielby J, et al., 2009, Global amphibian extinction risk assessment for the panzootic chytrid fungus, Diversity, Vol: 1, Pages: 52-66
Species are being lost at increasing rates due to anthropogenic effects, leading to the recognition that we are witnessing the onset of a sixth mass extinction. Emerging infectious disease has been shown to increase species loss and any attempts to reduce extinction rates need to squarely confront this challenge. Here, we develop a procedure for identifying amphibian species that are most at risk from the effects of chytridiomycosis by combining spatial analyses of key host life-history variables with the pathogen's predicted distribution. We apply our rule set to the known global diversity of amphibians in order to prioritize species that are most at risk of loss from disease emergence. This risk assessment shows where limited conservation funds are best deployed in order to prevent further loss of species by enabling ex situ amphibian salvage operations and focusing any potential disease mitigation projects. © 2009 by the authors; licensee Molecular Diversity Preservation International, Basel, Switzerland.
Loetters S, Kielgast J, Bielby J, et al., 2009, The Link Between Rapid Enigmatic Amphibian Decline and the Globally Emerging Chytrid Fungus, ECOHEALTH, Vol: 6, Pages: 358-372, ISSN: 1612-9202
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- Citations: 50
Howard SJ, Cerar D, Anderson MJ, et al., 2009, Frequency and Evolution of Azole Resistance in <i>Aspergillus fumigatus</i> Associated with Treatment Failure, 46th Interscience Conference on Antimicrobial Agents and Chemotherapy, Publisher: CENTERS DISEASE CONTROL & PREVENTION, Pages: 1068-1076, ISSN: 1080-6040
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- Citations: 599
James TY, Litvintseva AP, Vilgalys R, et al., 2009, Rapid Global Expansion of the Fungal Disease Chytridiomycosis into Declining and Healthy Amphibian Populations, PLOS PATHOGENS, Vol: 5, ISSN: 1553-7366
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- Citations: 166
Garner TWJ, Walker S, Bosch J, et al., 2009, Life history tradeoffs influence mortality associated with the amphibian pathogen <i>Batrachochytrium dendrobatidis</i>, OIKOS, Vol: 118, Pages: 783-791, ISSN: 0030-1299
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- Citations: 180
Soto-Azat C, Clarke BT, Fisher MC, et al., 2009, Non-invasive sampling methods for the detection of <i>Batrachochytrium dendrobatidis</i> in archived amphibians, DISEASES OF AQUATIC ORGANISMS, Vol: 84, Pages: 163-166, ISSN: 0177-5103
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- Citations: 31
Garner TWJ, Stephen I, Wombwell E, et al., 2009, The Amphibian Trade: Bans or Best Practice?, ECOHEALTH, Vol: 6, Pages: 148-151, ISSN: 1612-9202
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- Citations: 29
Garner TWJ, Garcia G, Carroll B, et al., 2009, Using itraconazole to clear <i>Batrachochytrium dendrobatidis</i> infection, and subsequent depigmentation of <i>Alytes muletensis</i> tadpoles, DISEASES OF AQUATIC ORGANISMS, Vol: 83, Pages: 257-260, ISSN: 0177-5103
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- Citations: 70
Fisher MC, Bosch J, Yin Z, et al., 2009, Proteomic and phenotypic profiling of the amphibian pathogen <i>Batrachochytrium dendrobatidis</i> shows that genotype is linked to virulence, MOLECULAR ECOLOGY, Vol: 18, Pages: 415-429, ISSN: 0962-1083
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- Citations: 132
Meyer W, Aanensen DM, Boekhout T, et al., 2009, Consensus multi-locus sequence typing scheme for <i>Cryptococcus neoformans</i> and <i>Cryptococcus gattii</i>, MEDICAL MYCOLOGY, Vol: 47, Pages: 561-570, ISSN: 1369-3786
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- Citations: 355
Fisher MC, Garner TWJ, Walker SF, 2009, Global Emergence of <i>Batrachochytrium dendrobatidis</i> and Amphibian Chytridiomycosis in Space, Time, and Host, ANNUAL REVIEW OF MICROBIOLOGY, Vol: 63, Pages: 291-310, ISSN: 0066-4227
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- Citations: 500
Fisher MC, 2008, Molecular toolkit unlocks life cycle of the panzootic amphibian pathogen <i>Batrachochytrium dendrobatidis</i>, PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, Vol: 105, Pages: 17209-17210, ISSN: 0027-8424
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- Citations: 6
Walker SF, Bosch J, James TY, et al., 2008, Invasive pathogens threaten species recovery programs, CURR BIOL, Vol: 18, Pages: R853-R854, ISSN: 0960-9822
Mitchell KM, Churcher TS, Garner TWJ, et al., 2008, Persistence of the emerging pathogen <i>Batrachochytrium dendrobatidis</i> outside the amphibian host greatly increases the probability of host extinction, PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES, Vol: 275, Pages: 329-334, ISSN: 0962-8452
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- Citations: 85
Pryce-Miller E, Aanensen D, Vanittanakom N, et al., 2008, Environmental detection of <i>Penicillium marneffei</i> and growth in soil microcosms in competition with <i>Talaromyces stipitatus</i>, FUNGAL ECOLOGY, Vol: 1, Pages: 49-56, ISSN: 1754-5048
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- Citations: 9
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