Host factors in determining resistance to cryptosporidiosis in cattle

Lead Research Organisation: The James Hutton Institute
Department Name: BioSS

Abstract

Cryptosporidium parasites are the most important cause of enteric disease in young cattle in UK and worldwide and are also one of the leading causes of infant diarrhoea in humans [1]. Neonatal calves are very vulnerable to cryptosporidiosis resulting in significant morbidity due to severe diarrhoea and dehydration and there are increasing reports of mortality. Cryptosporidiosis is a challenge to control as infected animals shed billions of infective, long lived oocysts into the environment and these are a source of infection for other animals as well as people. The disease has emerged as an increasing problem in beef suckler units, and livestock industry leaders are very concerned about the lack of safe and effective treatments or vaccines available to help prevent and control cryptosporidiosis and have given their strong support for this proposal.
Our understanding of the host-pathogen interactions that determine disease outcome is limited. Neonatal calves are very vulnerable to infection and often exhibit clinical disease, whereas older calves are more resistant. The factors involved in determining this age-related susceptibility are unclear and this project aims to address the host factors involved in resistance to cryptosporidiosis by applying novel and innovative in vivo, ex vivo and in vitro technologies to examine in detail the host parasite interaction during acute infection and recovery in calves.
One of the constraints for improving our understanding of the factors that determine disease resistance has been the lack of simple research systems that permit the detailed analysis of host parasite interactions. The rodent model is an acknowledged poor comparator for clinical disease in cryptosporidiosis in particular, and the capability for culturing Cryptosporidium parasites in vitro is very limited. This project aims to tackle these gaps in capability by utilising a combination of in vivo and in vitro bovine systems to assess innate and adaptive cellular immune responses and examine the interaction of Cryptosporidium with gut epithelial cells. In addition, innovative 3D bovine gut organoid in vitro culture systems will be applied to enable a detailed analysis of host parasite interactions in the bovine gut epithelium. Data derived from the experimental studies will be validated by comparison to similar data obtained from naturally infected calves on a study farm.
This project will provide the fullest exploration yet of how cattle resist infection with Cryptosporidium parasites. A detailed account of the host responses involved will provide an important knowledge platform that will enable the development of vaccines to aid disease prevention and the identification of relevant biomarkers that will enable selective breeding programmes to improve resilience. In addition, the development of novel in vitro bovine systems would revolutionise our capability to study host-pathogen interactions with Cryptosporidium minimising the need for use of animal models.
Outputs from the project will be of interest to the animal health industry, livestock producers, environmental and public health workers and to academic researchers. The development of effective control strategies will have a significant impact on the sustainable efficiency of animal production, safeguard food security, improve animal health and welfare, reduce waste and environmental contamination and improve public and environmental health.
[1] Streipen B (2013) Nature 503:189

Technical Summary

Cryptosporidium is a major cause of enteric disease in livestock. Our understanding of the host-pathogen interactions determining disease outcome is very limited. A notable aspect of bovine cryptosporidiosis is that neonatal calves are highly susceptible and often develop clinical disease, whereas older calves become infected but do not exhibit pathology. The factors underpinning this age-related susceptibility are very unclear, and this project aims to address the host factors involved in resistance to cryptosporidiosis. A significant current impediment for bovine cryptosporidiosis is the lack of a useful and relevant experimental model system to facilitate detailed analysis of host-parasite interaction. The rodent is a poor comparator for clinical disease in ruminants, and the ability to culture Cryptosporidium in vitro is limited. This project aims to tackle these gaps in capability and analyse in detail the innate and adaptive immune responses to Cryptosporidium infection in neonatal (< 1 week) and 6 week old cattle. We will (i) analyse the key cell-mediated immune responses during in vivo infections of naive calves (ii) analyse by confocal microscopy the initial host-parasite interaction in vitro using ex vivo derived epithelial primary cells from calves (iii) analyse host cell gene expression changes in response to parasite invasion and initial replication in the primary gut cells (iv) apply a 3D bovine gut organoid in vitro system to analyse the host-parasite interaction and explore the potential of propagating parasites in vitro and (v) examine translation of findings from experimental systems to a cohort of calves in the field. Outputs from the project will greatly improve our understanding of cattle resistance to cryptosporidiosis, informing vaccine development and breeding strategies and establishing an in vitro system that could revolutionise our capability to study relevant host-parasite interactions with Cryptosporidium.

Planned Impact

Cryptosporidiosis is the most important cause of enteric disease in young cattle in UK and worldwide and has also been cited as one of the leading causes of infant diarrhoea in humans by the WHO [1]. It is a neglected disease and there are no safe effective treatments or vaccines available to help prevent and control cryptosporidiosis. In discussions the applicants had with livestock producers leading to this proposal, farmers reported increased incidences of severe cryptosporidiosis within beef suckler units in Scotland. Beef industry leaders are very concerned about the lack of control options and have given their unreserved backing to this proposal in a letter of support.

The outputs from our project will make it possible to understand the host factors involved in determining resistance of cattle to cryptosporidiosis, which is essential to enable the development of prevention and control strategies based on vaccination and use of specific biomarkers in breeding programmes. In addition, infected livestock shed billions of parasites into the environment, resulting in an important source of infection for people and other animals. Cryptosporidium oocysts will survive for long periods in the environment and are resistant to normal water disinfection treatments and therefore pose significant economic and public health issues for water companies and governments.

Who might benefit from our project?

The outputs from our project will bring significant benefits to a wide range of different stakeholder groups. These include: those engaged in research involving protozoan parasites, bovine immunology and in vitro technologies applied to further our understanding of infectious disease; livestock producers from the dairy and beef industries; associated livestock health industries; environmental agencies, public health bodies; water companies; governments and policy makers and the public.

How might these stakeholders benefit from our project?

The research will be of great interest to academics in related scientific fields as the project will considerably improve our understanding of disease pathogenesis and host resistance to cryptosporidiosis in a relevant target host species. The application of innovative in vitro 3D culture technologies to enable detailed analysis of host-pathogen interactions in farm animal species will be of significant interest to researchers working to prevent and control infectious diseases of livestock and has the potential to substantially minimise the use of large animals in experiments going forward. We also wish to provide training for early career scientists in this area of research. Activity 1: Host international workshop on use of in vitro technologies to progress infectious disease research in livestock species.

The livestock industry in UK, and further afield, will benefit from the knowledge gained from our project by using new scientific evidence to direct resources effectively towards prevention and control strategies to tackle cryptosporidiosis. Outputs from the project will enable and target further work to test the feasibility of vaccination and using specific biomarkers to develop breeding programmes for improved resilience of livestock. We will also provide advice to livestock producers on managing Cryptosporidium infection on the farm. Activity 2: Host Industry day to discuss outputs from the project and identify collaborative areas going forward. Activity 3: Conduct on farm roadshow meetings in collaboration with farming organisations.

Policy makers, public health, environment and water companies will benefit from knowledge gained on how to control cryptosporidiosis on farms as this will reduce the resultant environmental contamination bringing economic and health benefits. Activity 4: Develop web-based materials and fact sheets on cryptosporidiosis prevention and control.

[1] Streipen B (2013) Nature 503: 189

Publications

10 25 50
 
Description The Cryptohost project aims to address the host factors involved in resistance to cryptosporidiosis in cattle by conducting complementary in vivo and in vitro studies to examine in detail the host-parasite interaction during acute infection and recovery. The project has been running since summer 2015.
Key Findings to date:

Cryptosporidium parvum oocysts have been used to conduct in vivo infections of neonatal calves to determine the host parasite interactions during acute infection and recovery. To derive the bovine intestinal organoid cultures, crypts were isolated from the ileum of calves and cultured successfully in vitro. The organoid cultures are currently being characterised through the analysis of gene expression and immunohistochemistry.
Exploitation Route We are optimistic that the findings may also be of use to others interested in host-pathogen interactions taking place in the bovine gut and mucosal system. We hosted a national workshop this year to look at how we might best utilise the bovine organoid culture system to help us understand host pathogen interactions in enteric diseases.
Sectors Agriculture, Food and Drink

 
Description We have been involved in outreach work related to prevention and control of Cryptosporidium on farms working with farming, veterinary and livestock industry stakeholders.
First Year Of Impact 2016
 
Description Beth Wells and Lee Innes spoke at the Strategic Research Programme CKEI strategy development meeting with the Cairngorms National Park Authority at Boat of Garten, on Cryptosporidium in the Environment
Geographic Reach National 
Policy Influence Type Participation in a national consultation
 
Title Multivariate methods and models for the analysis of data generated from a qualitative scoring system for the assessment of biological parameters 
Description Novel application of multivariate data analysis methods for the visualisation and modelling of faecal, overall health and feed data generated from naturally and experimentally infected animals which where assessed by direct observation using a pre-established scoring system. Particularly, (1) correspondence analysis and related statistical tests for the joint visualisation and assessment of the associations between scores and treatment groups, and (2) cumulative link mixed models for the modelling of repeated score-based measurements of biological parameters over the duration of the experiments. Unlike statistical analyses and summaries which assume ordinary quantitative measurements, these methods specifically accounted for the non-quantitative but qualitative and ordinal nature of the scores. 
Type Of Material Data analysis technique 
Year Produced 2018 
Provided To Others? No  
Impact The use of statistical methods and models which are coherent with the nature of the data contributes to the consistency, accuracy and reproducibility of results and scientific conclusions. 
 
Description Invited presentation to 100 dairy farmers 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Invited presentation on Cryptosporidium to 100 dairy farmers in Torun in Poland on the 2nd of March 2018
Year(s) Of Engagement Activity 2018
 
Description Article in Farmers Guardian 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact Sarah Thomson: Article in Farmers Guardian "Understanding cryptosporidiosis" 08-04-2016 https://www.fginsight.com/vip/vip/understanding-cryptosporidiosis-11330
Year(s) Of Engagement Activity 2016
 
Description Beef-Expo2016 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Lee Innes and Frank Katzer attended Beef-Expo2016 in Bakewell on the 20th of May 2016 to provide information on Cryptosporidium to farmers and veterinarians
Year(s) Of Engagement Activity 2016
 
Description CPD day involving Cryptosporidium for Downland SQPs from all over the UK 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Industry/Business
Results and Impact Beth Wells and Sarah Thomson organised and delivered a CPD day involving Cryptosporidium for Downland SQPs from all over the UK at Moredun Research Institute
Year(s) Of Engagement Activity 2016
 
Description Keynote Lecture at Apicowplexa 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact Keynote Lecture on "Food and Waterborne Protozoa" at Apicowplexa 4 4 in Madrid, Spain on the 14th of October 2017.
Year(s) Of Engagement Activity 2017
 
Description Keynote Lecture at the Sheep Veterinary Conference 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact Keynote Lecture on "Protozoan Parasites of Sheep" at the Sheep Veterinary Conference in Harrogate on the 25th of May 2017.
Year(s) Of Engagement Activity 2017
 
Description Moredun Foundation Livestock Health Roadshow 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Professional Practitioners
Results and Impact Frank Katzer gave a presentation on Cryptosporidium to farmers and veterinarians at the Moredun Foundation Livestock Health Roadshow in Macclesfield on the 7th of November 2016
Year(s) Of Engagement Activity 2016
 
Description National Sheep Show 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Frank Katzer attended the National Sheep Show in Malvern on the 28th of July 2016 to provide information on Cryptosporidium to farmers and veterinarians
Year(s) Of Engagement Activity 2016
 
Description Presentation at AgriScot 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Industry/Business
Results and Impact Presentation on Cryptosporidium at AgriScot at the Royal Highland Showground on the 15th of November 2017.
Year(s) Of Engagement Activity 2017
 
Description Presentation at Agriscot Agricultural event 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact Presentation on the prevention and control of cryptosporidiosis
Year(s) Of Engagement Activity 2018
 
Description Presentation at the Beef Expo 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact Presentation on Cryptosporidium in cattle at the Beef Expo at Stoneleigh Park, Warwickshire on the 18th of May 2017.
Year(s) Of Engagement Activity 2017
 
Description Sarah Thomson gave a talk MSc students from Edinburgh University 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Postgraduate students
Results and Impact Sarah Thomson gave a talk MSc students from Edinburgh University on Cryptopsoridiosis in farm livestock
Year(s) Of Engagement Activity 2016
 
Description Talk on Cryptosporidium to Food Standard Scotland representatives 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Supporters
Results and Impact Frank Katzer gave a talk on Cryptosporidium to Food Standard Scotland representatives at a meeting at Moredun
Year(s) Of Engagement Activity 2016