Tracking Marine sources of a Cholera outbreak using high throughput molecular methods on archival samples

使用高通量分子方法对档案样本追踪霍乱爆发的海洋来源

• 批准号: NE/S013431/1
• 负责人: Rowena Stern
• 金额: $ 5.4万
• 依托单位: Marine Biological Association of the United Kingdom
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FS013431%2F1
• 关键词: Tracking; Marine; sources; Cholera; outbreak

Vibrio cholerae is a marine bacteria living and feeding on the surfaces of tiny microscopic animals called zooplankton in the upper oceans. Zooplankton are dispersed by ocean currents and so Vibrio cholerae bacteria can spread to different regions via this route potentially spreading infections. Vibrio bacteria increase in numbers when sea surface temperatures have increased and tiny microscopic animals called zooplankton are at high abundance. In humans, V. cholerae causes Cholera, a diarrhoeal disease along with skin infections, meningitis and septicaemia if contaminated seafood is consumed or by bathing in contaminated waters. V. cholerae can also live in fresh or brackish water and so can infect people drinking contaminated freshwater too. There are many different variant forms of V. cholerae. In warmer climates, epidemic O1 and 0139 variants exist and are endemic. These cause severe gastrointestinal disease leading to fatalities. However, a multitude of non-severe variants exist in temperate Northern oceanic regions, such as UK and Canada, and these have a more favourable outcome. However non-severe types can evolve to become pathogenic thus it is important to monitor strain types to better predict and provide early warning for potential infectious events. Genetic methods are the best way to measure and track the multitude of ever changing Vibrio cholerae strains and several databases exist mapping the global distribution of different strains, including the European Union Reference Laboratory (EURL) hosted by CEFAS, the UK government lab that tests for food and water safety in UK waters. A recent outbreak of V. cholera occured in April 2018 in Vancouver Island, British Columbia on the Northwest coast of Canada causing four people to suffer cholera infection after consuming fish eggs. This is a rare occurence in temperate oceanic waters. This event happened soon after a recent unusal marine heatwave in this region between 2014-2016 and we are interested in determining whether the higher sea surface temperatures had altered zooplankton communities to enable pathogenic V. cholerae to thrive. Such events may happen in UK water as the English Channel and North sea are the fastest warming waters surrounding the UK. The waters surrounding BC Canada are regularly sampled by the Continuous Plankton Recorder (CPR) survey that also records zooplankton species and additionally by the Department of Fisheries and Oceans (DFO) in Canada that have captured water very near the site of infection. Although CPR samples are preserved in formalin which makes genetic detection difficult, we have nevertheless been able to quantify and detect variants of Vibrio from CPR samples. We propse a pilot study to concentrate up Vibrio cholerae using Whole Genome Enrichment in these samples to allow all of the variants of this bacteria to be detected using high-throughput sequencing. This will allow us to detect the infectious types and, by comparing them with strains from EURL, find out where they came from, whether the strain started out as infectious and if they are found elsewhere (such as UK waters) and the route they travelled to end up in Vancouver Island.We will also find out if the extent that increased sea surface temperatures allow human infectious Vibrio cholerae to increase and persist in local waters and in wider oceanic regions. As zooplankton act as hosts to Vibrio cholerae, we will determine if there are certain zooplankton species or groups of zooplankton that harbour this pathogen and facilitate its dispersal and persistence in oceanic waters. This will allow us to work out if this is these human infectious Vibrio cholerae strains are a transient or persistent threat and the environmental conditions in which they thrive. We will trasnmit this information to local governmental monitoring agencies to allow them to set up an early warning system if they find this bacteria again.

霍乱弧菌是一种海洋细菌，生活在上层海洋中被称为浮游动物的微小微型动物的表面并以其为食。浮游动物通过洋流传播，因此霍乱弧菌可以通过这一途径传播到不同的地区，可能会传播感染。当海洋表面温度升高，被称为浮游动物的微小微型动物数量增加时，弧菌的数量就会增加。在人类中，如果食用受污染的海鲜或在受污染的水中洗澡，霍乱弧菌会导致霍乱，这是一种腹泻疾病，并伴有皮肤感染、脑膜炎和败血症。霍乱弧菌也可以生活在淡水或咸水中，因此也可以感染饮用受污染淡水的人。霍乱弧菌有许多不同的变种。在较温暖的气候中，流行的O1和0139变种存在，并且是地方性的。这些疾病会导致严重的胃肠道疾病，导致死亡。然而，在温带北部海洋地区，如英国和加拿大，存在大量不严重的变种，这些变种具有更有利的结果。然而，非严重类型可能演变为致病性，因此监测毒株类型以更好地预测和提供潜在感染事件的早期预警是很重要的。基因方法是测量和跟踪不断变化的霍乱弧菌菌株数量的最佳方式，现有的几个数据库绘制了不同菌株的全球分布图，包括由CEFAS主办的欧盟参考实验室(EURL)，CEFAS是英国政府的实验室，测试英国水域的食品和水安全。加拿大西北海岸不列颠哥伦比亚省温哥华岛最近于2018年4月爆发霍乱，导致4人在食用鱼蛋后感染霍乱。这在温带海洋水域中很少见。这一事件发生在2014-2016年间该地区最近一次罕见的海洋热浪之后不久，我们有兴趣确定较高的海面温度是否改变了浮游动物群落，使致病性霍乱弧菌能够茁壮成长。这样的事件可能会发生在英国水域，因为英吉利海峡和北海是英国周围变暖最快的水域。加拿大不列颠哥伦比亚省周围水域定期通过连续浮游生物记录器(CPR)调查进行采样，该调查还记录浮游动物物种，此外还由加拿大渔业和海洋部(DFO)在感染地点附近捕获水。尽管CPR样本保存在福尔马林中，这使得遗传检测变得困难，但我们仍然能够从CPR样本中量化和检测弧菌的变体。我们提出了一项试点研究，利用这些样本中的全基因组浓缩来集中霍乱弧菌，以便使用高通量测序来检测这种细菌的所有变体。这将使我们能够检测感染类型，并通过将它们与EURL的菌株进行比较，找出它们来自哪里，这种菌株最初是否具有传染性，它们是否在其他地方(如英国水域)被发现，以及它们经过的路线最终到达温哥华岛。我们还将发现，海洋表面温度的上升是否允许人类传染性霍乱弧菌在当地水域和更广泛的海洋地区增加并持续存在。由于浮游动物是霍乱弧菌的宿主，我们将确定是否有某些浮游动物物种或浮游动物群体携带这种病原体，并促进其在海洋水域中的扩散和持续。这将使我们能够弄清楚这些人类传染性霍乱弧菌菌株是暂时的还是持续的威胁，以及它们茁壮成长的环境条件。我们将把这些信息传递给当地政府监测机构，以便他们在再次发现这种细菌时建立早期预警系统。

项目成果

Advances in Phytoplankton Ecology

浮游植物生态学进展

• 发表时间: 2021
• 作者: Stern, R.

Continuous Plankton Recorder in the omics era: from marine microbiome to global ocean observations

组学时代的连续浮游生物记录仪：从海洋微生物组到全球海洋观测

• DOI: 10.1016/j.copbio.2021.07.016
• 发表时间: 2022
• 期刊: Current Opinion in Biotechnology
• 影响因子: 7.7
• 作者: Vezzulli, Luigi;Martinez-Urtaza, Jaime;Stern, Rowena
• 通讯作者: Stern, Rowena