Production systems bird welfare and endemic disease affect the susceptibility of chickens to Campylobacter

Lead Research Organisation: University of Liverpool
Department Name: Institute of Infection and Global Health

Abstract

Campylobacter spp. are extremely important food borne enteropathogenic bacteria, estimated to cause over 600,000 cases of infection in the UK each year with around 100 deaths. It is estimated that Campylobacter infections cost the UK economy around £1 billion per year. Infection is characterised by acute and sometimes bloody diarrhoea, particularly in children. The last few years have seen a marked rise in cases in compromised elderly populations and in such people, particularly those with bowel cancer, infection can be fatal. Chicken meat is the most important source and vehicle for human Campylobacter infections and around 80% of chickens on sale in the UK are Campylobacter-positive. Campylobacter are natural inhabitants of the intestinal tract of chickens and other food animals. Contamination of chicken meat takes two forms. Carcass surfaces can carry high levels of Campylobacter and this can lead to cross-contamination in both domestic and commercial catering. This is an important risk factor for infection. However, and perhaps more importantly, Campylobacter have been recovered from deep muscle tissues of up to 27% of chickens tested. Furthermore, liver tissues are also commonly contaminated. In these tissues the bacteria will be better protected from the effects of cooking. Undercooked chicken meat and chicken liver pate are internationally important vehicles of Campylobacter infection. To improve public health in the UK it is essential that the number of contaminated chickens on sale is reduced. The proposed research will examine the different systems in which UK chickens are grown to identify cost-effective farm-based control options. Our work will focus on chickens reared intensively in housed systems as these comprise ~90% of the UK market. The work will be in collaboration with the three biggest poultry producers in the UK and all the major UK food retailers are giving financial support. The proposed research builds on past studies which showed that chikens (broilers) reared under higher welfare systems are less likely to have Campylobacter than birds reared more intensively. The higher welfare systems generally use slower-growing birds and stock houses with fewer birds than the more intensive systems. Our work showed that birds reared in the more intensive system had poorer welfare, as shown by high rates of endemic disease and general health and leg problems. This might explain why these birds were more likely to be Campylobacter-positive, as birds compromised by poor health and/or welfare are more susceptible to these bacteria. These differences might be due to the birds used and/or the in-house environment and we will determine this. Our field work might also indicate that the slower-growing bird types may be inherently more Campylobacter-resistant. We will conduct longitudinal studies on flocks reared under different systems and determine when birds first become Campylobacter-positive and relate this to changes in bird health and welfare. We will also determine whether the spread of Campylobacter from the intestine of the birds to edible tissues like liver occurs on farm and if it is linked to poor welfare for endemic disease. Our aim is to provide the UK poultry industry with science-based and cost-effective control options, which will help it meet customer demands and comply with forth-coming EU legislation aimed at reducing the number of chickens that are Campylobacter-positive.

Technical Summary

Chicken is the source of ~80% of human Campylobacter infections. The bacteria are found on carcass surfaces at high levels and in muscle and liver tissues. Undercooked chicken meat is an important vehicle of Campylobacter infection. It is essential that the number of contaminated chickens is reduced. The proposed research will examine different intensive systems in which UK chickens are grown and determine reasons for the observed differences in Campylobacter status. This project results from a direct request from the UK poultry industry. This proposal brings together modellers, microbiologists, molecular biologists, retailers and poultry producers in a unique combination to address global risks to human health associated with interactions between broiler production systems, endemic disease and physiological state of birds. Our past work showed that chickens reared under higher welfare systems are less likely to have Campylobacter than standard birds. The higher welfare systems use birds that grow more slowly and which are stocked at a lower density. As well as lower Campylobacter levels, the higher welfare birds had better health and this may protect them against Campylobacter. We seek to determine, through field studies, which of bird genotype/growth and/or the in-house environment determine Campylobacter status and to identify the mechanisms by which Campylobacter leave the chicken gut and infect edible tissues. We will use a combined modelling and molecular approach to investigate factors that improve resistance to Campylobacter, reduce risk of colonization and extra-intestinal spread in UK broilers. We will undertake laboratory studies to determine the susceptibility of commonly used broiler chickens to C. jejuni and the major endemic poultry pathogen avian pathogenic E. coli (APEC). Infection with E. coli not only increases the risk of broilers having Campylobacter, but is also strongly correlated with spread from the gut.

Planned Impact

Campylobacter is the most important food borne zoonosis in the UK and the wider EU. In the UK it is estimated that there are 600000 cases of infection in the UK each year and that Campylobacter infection costs the UK economy ~£1 billion per year. Chicken is overwhelmingly the most important vehicle for human infection and is believed to be responsible for up to 80% of infections. Furthermore, ~80% of chickens on sale in the UK are Campylobacter-positive. Contaminated chicken presents two health threats. Surface contamination levels can reach 109 cfu per carcass and contamination of deep muscle and liver tissues has been reported in up to 27 and 60% of samples tested respectively. The project seeks to better understand the impact of broiler chicken production systems, the resistance of the birds to infection with Campylobacter and its in vivo behaviour in the bird. We have shown that birds reared in higher welfare housed systems such as the RSPCA-backed Freedom Foods scheme, have lower Campylobacter levels and fewer risk factors for Campylobacter colonisation such as endemic diseases and poor gut health than birds reared in standard production systems. We seek to determine why these commonly used production systems differ so markedly and we will be determining the single and combined impacts of bird genotype/growth rate, endemic disease and bird stocking density, which affects the in-house environment. By comparing the different systems, we will be able to identify farm-based control measures that will reduce levels of Campylobacter in UK poultry and also improve the welfare of the birds. By better understanding the epidemiology of a major poultry endemic disease, APEC, measures can be identified to better control it. This will improve bird health and welfare, increase industry profitability and reduce the carbon footprint of UK poultry production. The project is in partnership with the UK poultry industry and all major UK retailers. Thus the beneficial impacts of ur work can quickly be transferred to stakeholders.

Publications

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Wigley P (2015) Blurred Lines: Pathogens, Commensals, and the Healthy Gut. in Frontiers in veterinary science

 
Description The research has shown that Campylobacter can cause mild disease in some commonly used chicken breeds. This can lead to diarrhoea and as a result of the birds standing on wet litter, it can lead to damage on their feet and legs.
We have shown how Campylobacter spreads through a flock and that there is huge variation between different strains or types of Campylobacter in where they infect and the risk they pose in causing human disease.
We have also shown the 'natural' immune response in the chicken is not one that clears infection from the gut, but prevent Campylobacter moving from the gut
Exploitation Route 1. Improvements to chicken breeding can be made to reduce the welfare impact of Campylobacter infection as well as reducing the risk of human infection.
2. Improved understanding of the immune response to infection will underpin vaccine development.
3. Better understanding of where Campylobacter may be located in the chicken gut may help reduce the risk of carcass contamination in processing.
Sectors Agriculture, Food and Drink,Healthcare

 
Description Understanding the impact of Campylobacter on chicken welfare is a factor in driving change in chicken breeds used for meat production. We have shown for the first time that Campylobacter is more than a' harmless commensal' and impacts on the health and welfare of the birds themselves. We also have shown the infection ecology of Campylobacter is very strain dependent. Previously it was assumed colonisation was largely in the lower intestinal tract. We have shown that colonisation can occur in the crop and the small intestine with some isolates. Controls in processing have been based upon the bacterium being localised in the caeca. The finding that Campylobacter is more widespread in the birds gut has important implications for control in processing. We have also determined there is considerable variation in how invasive isolates are in both the chicken and human epithelial cell lines meaning some isolates pose a greater risk of extra intestinal spread, again having direct implications in the food chain risk. Impacts fed directly to industry via stakeholder meetings to producers, supermarkets and breeding companies as well as through publication. The work was also presented directly to the Food Standards Agency Working Group on Campylobacter. Our development of in vivo models has also led directly to a research contract with DuPont on probiotics in Campylobacter infection
First Year Of Impact 2014
Sector Agriculture, Food and Drink
Impact Types Economic

 
Description Caecal Microbiome Transplant:a novel approach to Campylobacter control and improving broiler chicken gut heath
Amount £268,745 (GBP)
Funding ID BB/R008914/1 
Organisation Biotechnology and Biological Sciences Research Council (BBSRC) 
Sector Public
Country United Kingdom
Start 04/2018 
End 03/2020
 
Description Industrial Award
Amount £152,000 (GBP)
Organisation DuPont 
Sector Private
Country United States
Start 04/2015 
End 09/2016
 
Description Rapid diagnostics and control strategies for enteric bacterial pathogens in backyard and commercial poultry production in Thailand and the Philippines
Amount £916,765 (GBP)
Funding ID BB/R013136/1 
Organisation Biotechnology and Biological Sciences Research Council (BBSRC) 
Sector Public
Country United Kingdom
Start 04/2018 
End 03/2021
 
Title Avian Infection Models 
Description Development and refinement of novel infection models to study infection, co-infection and transmission by food borne bacterial pathogens 
Type Of Material Model of mechanisms or symptoms - non-mammalian in vivo 
Year Produced 2013 
Provided To Others? Yes  
Impact Publications and directly funded industrial research 
 
Description A twisted bugs life 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? Yes
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Hands on presentation/exhibit at Liverpool's World Museum then at the national festival in London. Giant walk through gut to understand how Campylobacter make people ill and various activities to show how one can reduce their risk of infection.

Much interest in how chicken can be source of infection and what can be done to reduce risks for adults and children
Year(s) Of Engagement Activity 2014
URL http://www.bbsrc.ac.uk/society/exhibitions/gb-bioscience-festival/twisted-bugs-life.aspx
 
Description Brazil Poultry Industry meeting 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Lively discussion

None as yet
Year(s) Of Engagement Activity 2014
 
Description Christmas Lecture 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Lot's of interest and questions about infectious disease and vaccination

Interest in the lab's work.
Amusement of colleagues to being dressed as Father Christmas and Rudolph
Year(s) Of Engagement Activity 2013
 
Description Exchange visit Poultry Research an Diagnostic Dept, University of Georgia, Athens 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Professional Practitioners
Results and Impact Exchange visit to the University of Georgia to meet with researchers and vets working on foodborne pathogens and poultry research, to discuss work from this and other projects and to discuss future collaborations around Campylobacter in poultry in the UK and the USA to compare the different production systems and the epidemiology and infection biology of campylobacter in such systems. Professor Paul Wigley (PI) presented a overview of current work at Liverpool also covering this project
Year(s) Of Engagement Activity 2016
 
Description Food Standards Agency Campylobacter Working group 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Policymakers/politicians
Results and Impact Much interest in what was presented. Presented scientific evidence to working group of greater potential problems in Campylobacter control than previously thought, but that immunological intervention may work

Interest in having additional information and a 'lay version' of subsequently published papers
Year(s) Of Engagement Activity 2013
 
Description Healthy tums, happy bums 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Lot's of interest in food safety and what can be done to safer handle and prepare food

General public interest
Year(s) Of Engagement Activity 2013
URL http://news.liv.ac.uk/2013/06/14/food-safety-on-the-menu-at-liverpools-world-museum/
 
Description Poultry Disease Group 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Contribution to Poultry Disease Group Forum through presentations and discussion. Excellent forum to link academia, industry and policymakers

Frequent requests for information, links to industry
Year(s) Of Engagement Activity 2010,2011,2012,2013
 
Description Presentation to CEVA Animal health 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact Meeting/visit to CEVA in Bordeaux to discuss development of poultry vaccines with their international poultry committee. This has become recurring activity with presentations made twice in 2016 and further made for July 2017
Year(s) Of Engagement Activity 2015,2016
 
Description Presentation to MSD Animal health 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Good discussion with regard to future potential collaboration

Sharing of information on immune response to Salmonella
Year(s) Of Engagement Activity 2012
 
Description Presentations to representatives from poultry breeders, producers and retailers 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact The talks stimulated much discussion towards methods of reduction of Campylobacter and improvements that could be made to health and welfare

Retailers and producers highly interested in research presented and how it may be applied. Improved understanding of impact of infection on animal welfare
Year(s) Of Engagement Activity 2010,2011,2012,2013,2014
 
Description Press releases and interviews relating to foodborne infections 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact Press releases appeared in multiple general and specific outlets. In particular over 20 interviews were given during the 2011 E. coli O104 outbreak including national TV interviews and international radio and print media interviews.

Increased interest in the group's activities and invitations to speak at conferences. Further media interviews and comments especially for BBC news website.
Year(s) Of Engagement Activity 2009,2011,2012,2013,2014
 
Description School Visit-Neston 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact Primary school visit explaining about animals using bones in a demonstration. Was enjoyed by children who understood more about the biology of current and extinct animal species

None yet
Year(s) Of Engagement Activity 2014,2015,2016
 
Description Talks on infectious disease to 6th form and parents & talk to 5th and 6th form on use of animals in science 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact General discussion afterwards. Specific interest from some individuals

Students undertaking work experience in lab.
Applications to our degree programmes
Year(s) Of Engagement Activity 2007,2009,2010
 
Description Thai Poultry Industry Meeting 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Many questions but limited time

Questions on what future contra strategies may be
Year(s) Of Engagement Activity 2013
 
Description Workshop and visits to Corpoica, Pollo Fiesta, Colombian NIH and Biotech Institutes in Bogota, Colombia on foodborne pathogens and food safety 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact The key objective of our visit was to understand the structure and challenges faced by the Colombian poultry industry in controlling the foodborne pathogens, Campylobacter and Salmonella, and to disseminate our findings and the approaches that we have taken within the UK and ultimately to explore translation of work to improving food safety in Colombia. This was facilitated through meetings with academics and the poultry industry, as well as visiting poultry farms and slaughterhouses, which provoked discussion around biosecurity on the farms and how this could be improved as well as interventions within the slaughterhouse. These included the production company Pollo Fiesta, researchers from Corpoica, Universities and the National Institute for Health. Alex Royden a BBSRC DTP PhD student also spent time at Corpoica and helped train staff in some of our isolation procedures developed here which helped overcome some of the issues they had with contamination when trying to isolate Campylobacter.
Year(s) Of Engagement Activity 2017
 
Description Workshops on Campylobacter and Salmonella Bangkok and Pattaya, Thailand 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other academic audiences (collaborators, peers etc.)
Results and Impact Workshops promoted discussion and development of Thai research programme

Visiting Thai students
Year(s) Of Engagement Activity 2012,2013