̽��ֱ�� of Cambridge - pathogen

Enemy at the gates: the battle to save our crops

ta385 — Wed, 22 May 2019 07:00:00 +0000

A gene newly-linked to plant self-defence may hold the key to saving important crops from a deadly disease, scientists at Cambridge's Sainsbury Laboratory now hope.

Oldest genetic evidence of Hepatitis B virus found in ancient DNA from 4,500 year-old skeletons

Anonymous — Wed, 09 May 2018 17:00:00 +0000

A pioneering study has identified the oldest evidence of HBV in the ancient remains and proved that viruses can become extinct. ̽��ֱ��scientific significance of the research has been described as ‘truly remarkable’ and compared to the discovery of the first fossils.

Today the Hepatitis B virus affects millions of people worldwide. In 2015 it was estimated that approximately 257 million people were chronically infected with HBV and 887,000 died due to associated complications such as liver cancer.

̽��ֱ��new research, led by a group of academics at the Centre for Pathogen Evolution in the Department of Zoology at the ̽��ֱ�� of Cambridge and the Centre for GeoGenetics at the ̽��ֱ�� of Copenhagen, took genetic samples from skeletons across Europe and Asia from the Bronze Age to the Medieval period, and found 25 HBV-positive skeletons amongst the remains. In 12 of these skeletons, they found enough of the HBV genome to perform detailed analyses - the oldest of which was 4,500-years-old.

From this data they were able to extract the genetic sequences of HBV that infected the individuals thousands of years ago.

̽��ֱ��findings, published in the journal Nature, present new insights into the origins and evolution of HBV. ̽��ֱ��genetic makeup of this strain could have implications for improving vaccines for HBV.

Before this study, the oldest human viruses to be discovered were approximately 450-years- old but most are no more than 50-years-old. ̽��ֱ��research now forms the oldest and largest datasets scientists have of ancient human viruses.

Barbara Mühlemann, joint first author on the research paper and a graduate student at the ̽��ֱ�� of Cambridge, said: “People have tried to unravel the history of HBV for decades - this study transforms our understanding of the virus and proves it affected people as far back as the Bronze Age. We have also shown that it is possible to recover viral sequences from samples of this age which will have much wider scientific implications.”

Although HBV is a global health issue, little is known about its origin and evolution. As with many human viruses, this is largely due to a lack of historical evidence which has been difficult to locate and identify.

Dr Terry Jones, joint first author who is based at the ̽��ֱ�� of Cambridge’s Department of Zoology, explained: “Scientists mostly study modern virus strains and we have mainly been in the dark regarding ancient sequences – until now. It was like trying to study evolution without fossils. If we only studied the animals living today it would give us a very inaccurate picture of their evolution – it is the same with viruses.”

Understanding more about HBV may now be possible. Showing that the virus has been circulating in humans since at least the Bronze Age is a big scientific advancement, as previous attempts to estimate how long the virus has infected humans have ranged from 400 years to 34,000 years.

̽��ֱ��study was led by Professor Eske Willerslev, who holds positions both at St John’s College, ̽��ֱ�� of Cambridge, and the ̽��ֱ�� of Copenhagen.

He said: “This data gives us an idea of how this virus behaves, and it provides us with a better idea of what is biologically possible in the future. Analysis of other ancient DNA samples may reveal further discoveries and this pioneering study could have huge implications for how the virus affects humans today.”

̽��ֱ��research also shows the existence of ancient HBV genotypes in locations incompatible with their present-day distribution, contradicting previously-suggested geographical origins of the virus.

Professor Willerslev initially suspected that it might be possible to find viruses in human remains based on previous research during his role at the ̽��ֱ�� of Copenhagen. He approached Mühlemann and Jones who have specialised in identifying and studying the evolution of viruses.

̽��ֱ��research approach the group used in the study, called ‘shotgun sequencing’, looks at all genetic material present in a sample, as opposed to ‘genome bio-capture’ which focuses only on the human genome.

Professor Willerslev said: “This study is just the start. We’re talking about one virus here, but there are a lot of other viruses we could look for.”

Reference:
Barbara Mühlemann et al. 'Ancient Hepatitis B viruses from the Bronze Age to the Medieval period.' Nature (2018). DOI: 10.1038/s41586-018-0097-z

An extinct strain of the human Hepatitis B virus (HBV) has been discovered in Bronze Age human skeletons found in burial sites across Europe and Asia.

This study could have huge implications for how the virus affects humans today.

Eske Willerslev

Alexey A. Kovalev

Mass burial of battle victims from the Xiongnu period in Omnogobi, Mongolia, from which scientists extracted ancient DNA from for the study.

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

Yes

Experts advocate for stronger measures to protect trees and other plants from pests and pathogens

gm349 — Mon, 20 May 2013 09:36:58 +0000

As the fungus responsible for ash dieback continues to devastate ash tree populations throughout the UK and other threats to the countryside continue to emerge, experts convened by Defra are advocating for stronger measures to protect the UK’s trees and plants.

̽��ֱ��independent Tree Health and Plant Biosecurity Expert Taskforce was established by Defra’s Chief Scientific Adviser, Professor Ian Boyd, late last year to address the current and emerging threats to the UK’s trees and plants. Working with an advisory group made up of various stakeholder organisations, to include industry, Defra, and the Forestry Commission as well as Border Force, the taskforce is proposing a number of initiatives aimed at minimising the risk of plant pests and diseases.

Professor Chris Gilligan, chair of the taskforce and Professor of Mathematical Biology and Head of the School of Biological Sciences at the ̽��ֱ�� of Cambridge, said: “ ̽��ֱ��UK needs to be better prepared for threats to plant health. In the last few years alone, several previously unknown pests and pathogens have emerged, posing significant risks to the UK’s crops as well as trees in woodlands, commercial forests and in urban environments.

“By increasing our understanding of what pests and diseases are the biggest threats and how best to mitigate their impact, we can minimise potentially devastating outbreaks.”

̽��ֱ��scientists believe that the threats have increased because of globalisation in trade and travel and the subsequent escalation in volume and diversity of plants and plant products entering the UK, all of which potentially harbour plant pests and pathogens. Once established, pests and pathogens can wreak havoc on biodiversity, timber and crop production, the landscape and, in certain circumstances, human health. (In addition to Chalara, recent examples include horse chestnut leaf mining moth, oak processionary moth, bleeding canker of horse chestnut and Dothistroma needle blight on pines.)

Professor Charles Godfray, a member of the taskforce from the ̽��ֱ�� of Oxford’s Zoology Department & Oxford Martin School said: “Globalisation poses many challenges including to the health of our trees and other plants; the taskforce has tried to suggest proportionate measures that will materially lessen the risks to the nation’s trees and forests without adding unnecessary barriers to trade and commerce.”

Although the remit was to focus on trees and related woody species, the taskforce noted that many of the principles addressed in recommendations for tree health are applicable to pests and diseases that affect other plants (including agricultural, horticultural and biomass crops, indigenous vegetation and ornamental plants).

Taskforce recommendations

Currently, there are numerous risk assessments for individual pests and pathogens at both the national and European level. ̽��ֱ��taskforce recommends a single national Risk Register for plant health. This new UK Plant Health Risk Register would serve to identify and prioritise pests and pathogens that pose a threat to the UK and to identify what actions must be taken should the threat materialise.

̽��ֱ��taskforce is also advocating an individual at a senior level who is responsible for overseeing the UK Plant Health Risk Register and providing leadership for managing those risks. ̽��ֱ��Chief Plant Health Officer would work in a similar fashion as the Chief Veterinary Officer, who oversees animal-related emergencies.

̽��ֱ��appointee would also be responsible for developing and implementing procedures for preparedness and contingency planning to predict, monitor and control the spread of pests and pathogens. There was also a recommendation that current governance and legislation needed to be reviewed, simplified and strengthened.

Because of globalisation, more and more people and goods are travelling greater distances at an increasingly greater rate. As a result, there is a significant increase in the risk of introducing non-native pests and pathogens. In order to minimise the risks of introduction at the border, the taskforce has made several recommendations regarding the import of trees and other plants. They propose that no plant material for personal use be imported from outside the EU.

̽��ֱ��import of live plants, foliage, branches and other plant parts has seen a 71 per cent increase since 1999, dramatically increasing the risk a pathogen or pest might be introduced. Therefore they also propose the Plant Passport scheme, which currently only applies to some plants associated with pests and pathogens, be strengthened and also applied to seeds as a means of ensuring traceability (showing all ports of calls within the EU and last port before entry to the EU).

Dr Jens-Georg Unger, taskforce member and Head of the Institute for National and International Plant Health in Germany, said: “There have been too many introductions of serious new pests in recent years into EU countries - improvements are needed urgently. Efficient protection can only be achieved by more complete and faster exchange of information between countries and more focussed and better coordinated action in all EU countries. ̽��ֱ��UK taskforce is an extremely important step for the initiation of such improvements on the national and the EU level.”

Additional recommendations include improving the use of epidemiological intelligence from EU/other regions and work to improve the EU regulations concerned with tree health and plant biosecurity, developing a modern, user-friendly, system to provide quick and intelligent access to information about tree health and plant biosecurity, and addressing key skills shortages.

For more information about this story, please contact: Genevieve Maul, Office of Communications, ̽��ֱ�� of Cambridge. Email: Genevieve.Maul@admin.cam.ac.uk; Tel: 01223 765542.

Ash dieback, caused by the Chalara fungus, prompts re-evaluation of current protocols to protect UK trees and other plants; taskforce recommends threats to plant health be taken as seriously as animal disease

̽��ֱ��UK needs to be better prepared for threats to plant health. In the last few years alone, several previously unknown pests and pathogens have emerged, posing significant risks to the UK’s crops as well as trees in woodlands, commercial forests and in urban environments.

Professor Chris Gilligan, chair of the taskforce and Professor of Mathematical Biology and Head of the School of Biological Sciences at the ̽��ֱ�� of Cambridge

Forestry Commission

Drothistroma needle blight on pines

This work is licensed under a Creative Commons Licence. If you use this content on your site please link back to this page.

Yes