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A step towards new vaccines for most important chicken parasite

14 October 2011

Researchers funded by the Biotechnology and Biological Sciences Research Council (BBSRC), among others, have taken the first step in developing a new type of vaccine to protect chickens against coccidiosis, the most important parasite of poultry globally.

Second generation schizont of Eimeria tenella parasites growing in the caecum of the chicken.  Copyright  Professor DJP Ferguson, University of Oxford

Second generation schizont of Eimeria tenella parasites growing in the caecum of the chicken. Copyright: Professor DJP Ferguson, University of Oxford

A vaccine of this type - based on proteins from the coccidiosis bug rather than being derived from a live parasite - could be produced on a larger scale than is currently possible so could be used to provide much more widespread protection to chicken flocks.

Protecting against animal diseases is going to play an important role in ensuring global food security.

The researchers have produced a much more detailed picture of how coccidiosis attacks chickens, uncovering the protein molecules which are secreted onto the surface of the coccidiosis-causing-parasite, Eimeria, that allow it to attach-to and invade cells in a chicken's gut. The scientists also found that when purified and used to inoculate chickens, one of these molecules provided the birds with some protection against coccidiosis and so shows promise as the basis of a new vaccine.

The research was carried out by an international team with funding from BBSRC, the Engineering and Physical Sciences Research Council (EPSRC), the Medical Research Council (MRC) and the Wellcome Trust. The research is published today (13 October) in the journal PLoS Pathogens and the UK-based research took place at Imperial College London, the Institute for Animal Health, the University of Oxford and the Royal Veterinary College.

Professor Fiona Tomley of the Royal Veterinary College said "Coccidiosis is the most important parasite of poultry globally. Conservative estimates by the EU put the annual worldwide cost of coccidiosis at over £1billion so controlling it is very important economically but it is also valuable for improving the health and welfare of chickens."

Currently, coccidiosis is treated with antimicrobial drugs or using a vaccine derived from a live parasite. Both of these methods are problematic as drug resistance is widespread and the vaccine is relatively expensive to produce so cannot be used on a wide, preventative scale. Vaccines for some other diseases are based on single proteins rather than killed versions of the disease-causing bug. These so-called 'recombinant vaccines' offer a number of advantages over killed-disease vaccines as they are safer and can be produced more cheaply and quickly and on an industrial scale.

Second generation schizont of Eimeria tenella parasites growing in the caecum of the chicken.  Copyright  Professor DJP Ferguson, University of Oxford

Second generation schizont of Eimeria tenella parasites growing in the caecum of the chicken. Copyright: Professor DJP Ferguson, University of Oxford

The protein revealed in this study could form the basis of a recombinant vaccine. It is called MIC3 and is important in the early stages of a coccidiosis infection. MIC3 is secreted by the Emeria parasite and binds to sugar molecules on the surface of cells in the caecum, a section of the large intestine. Another scientist involved in this project, Professor Ten Feizi, and her team at Imperial College London, used a new and powerful technology known as carbohydrate microarray to study the particular sugar molecules which the parasite's MIC3 protein seeks out and binds.

Professor Stephen Matthews of Imperial College London said "Finding a target protein that could form the basis of a new type of vaccine for coccidiosis has been the holy grail for researchers combating coccidiosis for some time. The high resolution detail afforded by NMR spectroscopy on recombinant vaccines provides important clues for their optimal design, and paves the way for cost-effective and widespread protection against this important poultry disease."

Professor Douglas Kell, BBSRC Chief Executive, said "Finding new ways to combat diseases of farmed animals is going to be important to ensure global food security - but also to the UK economy. We have a valuable poultry breeding and production industry in this country so any steps towards a new vaccine for coccidiosis are a triumph. This work is a nice example of how studying the fundamental biology of a process at the most minute level could lead to new weapons in the fight against disease. It also underscores the increasing importance of biologics to the UK Bioeconomy".

ENDS

About Imperial College London

Consistently rated amongst the world's best universities, Imperial College London is a science-based institution with a reputation for excellence in teaching and research that attracts 14,000 students and 6,000 staff of the highest international quality. Innovative research at the College explores the interface between science, medicine, engineering and business, delivering practical solutions that improve quality of life and the environment - underpinned by a dynamic enterprise culture.

Since its foundation in 1907, Imperial's contributions to society have included the discovery of penicillin, the development of holography and the foundations of fibre optics. This commitment to the application of research for the benefit of all continues today, with current focuses including interdisciplinary collaborations to improve global health, tackle climate change, develop sustainable sources of energy and address security challenges.

In 2007, Imperial College London and Imperial College Healthcare NHS Trust formed the UK's first Academic Health Science Centre. This unique partnership aims to improve the quality of life of patients and populations by taking new discoveries and translating them into new therapies as quickly as possible. www.imperial.ac.uk

About IAH

The Institute for Animal Health, which received a total of £62.9M investment from the Biotechnology and Biological Sciences Research Council (BBSRC) in 2010-11, is a world-leading centre of excellence for research into viruses of farm animals, principally cattle, poultry, sheep, pigs plus horses. Our research extends from fundamental to applied research, from genes all the way through to animal populations. It is our belief that better control of viral diseases requires a greater understanding of how each virus causes disease, how the immune systems of the farm animals respond to infection, and how the viruses spread, including those distributed by insects and other arthropods. In this way we contribute to the development of smarter, more effective vaccines; develop more discriminatory, user-friendly diagnostics; provide diagnostic services; and give expert knowledge to guide policy makers and farmers.

About BBSRC

BBSRC invests in world-class bioscience research and training on behalf of the UK public. Our aim is to further scientific knowledge, to promote economic growth, wealth and job creation and to improve quality of life in the UK and beyond.

Funded by Government, and with an annual budget of around £445M, we support research and training in universities and strategically funded institutes. BBSRC research and the people we fund are helping society to meet major challenges, including food security, green energy and healthier, longer lives. Our investments underpin important UK economic sectors, such as farming, food, industrial biotechnology and pharmaceuticals.

For more information about BBSRC, our science and our impact see: www.bbsrc.ac.uk .
For more information about BBSRC strategically funded institutes see: www.bbsrc.ac.uk/institutes .