The spatial epidemiology and molecular evolution of panzootic amphibian chytridiomycosis

全动物两栖动物壶菌病的空间流行病学和分子进化

• 批准号: NE/K012509/1
• 负责人: Trenton Garner
• 金额: $ 26.69万
• 依托单位: Zoological Society of London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2014
• 资助国家: 英国
• 起止时间: 2014 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FK012509%2F1
• 关键词: spatial; epidemiology; molecular; evolution; panzootic

Modern-day amphibians are known to be suffering rates of extinction that far exceed any other class of vertebrates, including those experienced by mammals and birds, and nearly one third of amphibian species are threatened. The question of why amphibians are going extinct at these accelerated rates has puzzled scientists for three decades. A clue to the mystery came about when scientists working in Central America and Australia noted that the declines in amphibian biodiversity were spreading in a wave-like manner, from a point source. These patterns of decline were caused by an emerging infectious disease, and in 1997 researchers discovered the fungal pathogen and named it Batrachochytrium dendrobatidis (Bd). Since then, our research has been focused on finding out where the fungus is, where it is spreading to and what its effect is on amphibian biodiversity. We have made a mapping tool at www.bd-maps.net and this has shown that Bd occurs on all continents with amphibians. However, not all species and populations infected with Bd die, suggesting to us that there may be more than one strain (or lineage) of Bd and that these are not all equally destructive. Confirmation of this came when we used new whole genome sequencing technology to sequence isolates of Bd from around the world. We discovered three lineages of Bd, and showed that only one of them is responsible for mass mortalities and species declines. We named this lineage BdGPL for 'Bd Global Panzootic Lineage' and showed that it occured in Africa, Europe, Australia and America.Currently, several lines of argument suggest that BdGPL evolved in Africa. We will investigate this 'Bd Out-of-Africa' hypothesis by sequencing the genomes of Bd isolates widely across Africa and Europe, and undertaking fine-scale studies of the pathogens impact where it has been introduced into new environments. Our project will investigate both broad- and fine-scale processes, by characterising the genome diversity of Bd at the continental-level, but also focusing on fine-scale evolutionary patterns in Africa, the Pyrenees, the Alps and the UK. We will twin these genomic approaches with experimental approaches in order to determine whether invasive 'outbreak' lineages have altered their virulence and infectivity owing to accelerated evolution by the action of natural selection. Here, our expectation is that outbreak lineages that are adapting to new environments and hosts will have increased virulence and transmission rates when compared against the ancestral lineage in its original geographic background. These experiments will not only give us added certainty when determining the geographic origins of these infections, but will also allow us to assess why BdGPL is so much more virulent, and transmittable, than the other lineages of Bd.More widely, our research will inform us about the risk that new pathogens pose to uninfected environments. Currently, we are seeing many emerging pathogenic fungi causing untold destruction to forests, bats and frogs. Perhaps there are common processes that underlie these emergences of disease - not only global trade in infected goods but also genome-level processes that are unique to fungi? Projects such as that described here hold the key to answering these important questions before losses of biodiversity increase further.

众所周知，现代两栖动物的灭绝率远远超过了任何其他类别的脊椎动物，包括哺乳动物和鸟类经历的脊椎动物，以及将近三分之一的两栖动物受到威胁。为什么两栖动物以这些加速速率灭绝的问题使科学家困惑了三十年。当中美洲和澳大利亚工作的科学家指出，两栖动物生物多样性的下降是从点来源传播的。这些下降模式是由新兴的传染病引起的，1997年，研究人员发现了真菌病原体，并将其命名为batrachochochochytrium dendrobatidis（BD）。从那时起，我们的研究一直致力于找出真菌在哪里，散布到哪里以及其对两栖动物生物多样性的影响。我们已经在www.bd-maps.net上制作了一个映射工具，这表明BD发生在带有两栖动物的各大洲。但是，并非所有感染了BD死亡的物种和种群，这向我们表明，BD可能有多种菌株（或谱系），并且这些菌株并非全部具有破坏性。当我们使用新的整个基因组测序技术来对世界各地的BD隔离序列时，就会确认这一点。我们发现了三个BD谱系，并表明其中只有一个是造成质量死亡率和物种下降的原因。我们为“ BD全球Panzootic Lineage”命名了BDGPL这个血统，并表明它发生在非洲，欧洲，澳大利亚和美国。目前，有几条论点表明，BDGPL在非洲发展了。我们将通过对BD在非洲和欧洲进行广泛分离的基因组进行测序，并对病原体的细微研究进行了对已引入新环境的情况进行的精细研究，从而调查了这一“ BD脱非洲”假设。我们的项目将通过表征大陆级别的BD的基因组多样性来研究广泛的过程，但也关注非洲，比利牛斯山脉，阿尔卑斯山和英国的精细尺度进化模式。我们将采用实验方法进行这些基因组方法的双重研究，以确定由于自然选择的作用加速了进化而导致的侵入性“爆发”谱系是否改变了它们的毒力和感染力。在这里，我们的期望是，与原始地理背景相比，与祖先血统相比，适应新环境和宿主的爆发谱系将增加毒力和传输速率。这些实验不仅可以在确定这些感染的地理起源时给我们带来更多的确定性，而且还可以使我们能够评估BDGPL比BD的其他谱系更具毒性和可传播性更大。更广泛地为我们提供了更广泛的研究，我们的研究将为我们提供有关新病原体构成未感染环境的风险。目前，我们看到许多新兴的致病真菌造成了森林，蝙蝠和青蛙的无数破坏。也许有一些共同的过程是这些疾病出现的基础 - 不仅是全球受感染商品的贸易，而且是真菌独有的基因组水平过程？诸如此处描述的项目是在生物多样性损失进一步增加之前回答这些重要问题的关键。

项目成果

Assessing the ability of swab data to determine the true burden of infection for the amphibian pathogen Batrachochytrium dendrobatidis.

• DOI: 10.1007/s10393-016-1114-z
• 发表时间: 2016-06
• 期刊: EcoHealth
• 影响因子: 2.5
• 作者: Clare F;Daniel O;Garner T;Fisher M
• 通讯作者: Fisher M

Consistency of Published Results on the Pathogen Batrachochytrium dendrobatidis in Madagascar: Formal Comment on Kolby et al. Rapid Response to Evaluate the Presence of Amphibian Chytrid Fungus (Batrachochytrium dendrobatidis) and Ranavirus in Wild Amphibian Populations in Madagascar.

• DOI: 10.1371/journal.pone.0135900
• 发表时间: 2015
• 期刊: PloS one
• 影响因子: 3.7
• 作者: Bletz MC;Rosa GM;Andreone F;Courtois EA;Schmeller DS;Rabibisoa NH;Rabemananjara FC;Raharivololoniaina L;Vences M;Weldon C;Edmonds D;Raxworthy CJ;Harris RN;Fisher MC;Crottini A
• 通讯作者: Crottini A

Amphibian chytridiomycosis outbreak dynamics are linked with host skin bacterial community structure.

• DOI: 10.1038/s41467-018-02967-w
• 发表时间: 2018-02-15
• 期刊: Nature communications
• 影响因子: 16.6
• 作者: Bates KA;Clare FC;O'Hanlon S;Bosch J;Brookes L;Hopkins K;McLaughlin EJ;Daniel O;Garner TWJ;Fisher MC;Harrison XA
• 通讯作者: Harrison XA

Islands within an island: Population genetic structure of the endemic Sardinian newt, Euproctus platycephalus.

• DOI: 10.1002/ece3.2665
• 发表时间: 2017-02
• 期刊: Ecology and evolution
• 影响因子: 2.6
• 作者: Ball SE;Bovero S;Sotgiu G;Tessa G;Angelini C;Bielby J;Durrant C;Favelli M;Gazzaniga E;Garner TW
• 通讯作者: Garner TW

Climate forcing of an emerging pathogenic fungus across a montane multi-host community.

• DOI: 10.1098/rstb.2015.0454
• 发表时间: 2016-12-05
• 期刊: Philosophical transactions of the Royal Society of London. Series B, Biological sciences
• 作者: Clare FC;Halder JB;Daniel O;Bielby J;Semenov MA;Jombart T;Loyau A;Schmeller DS;Cunningham AA;Rowcliffe M;Garner TW;Bosch J;Fisher MC
• 通讯作者: Fisher MC