Pathway to Peste des Petits Ruminants Virus Elimination - methods for complex ecosystems

Lead Research Organisation: Royal Veterinary College
Department Name: Pathology and Pathogen Biology

Abstract

The emergence of the viral disease, peste des petits ruminants (PPR) across Asia and Africa, affecting some of the poorest and most challenged human communities on earth, demands urgent action to mitigate its immediate and ongoing insidious impacts on domestic and wild ruminants. PPR is a very severe disease of sheep and goats that is very common in East Africa causing high mortality of up to 100%, and loss of milk and meat. It threatens the food security and livelihoods of pastoralists and small-holder farmers. It also threatens wildlife resources, as die-off of rare and endangered wild caprines in Asia has shown. Over the past few years there has been much discussion at international and national levels about the control and possible eradication of PPR, and in early 2015 a global PPR eradication programme was launched.
Since the emergence of PPR in Kenya and Tanzania in 2006-2008, there have been several vaccination campaigns to limit its impact on livestock keepers but outbreaks continue to occur, and lack of effective surveillance means that it is unclear how and where the virus is persisting. Vaccination is usually applied in response to outbreaks if funds are available, which helps to reduce livestock keepers' immediate losses due to the disease, but low levels of vaccination coverage could be contributing to virus persistence. A more pragmatic but research-driven approach is needed to halt PPR virus persistence and spread in East Africa, as well as in infected and at-risk areas of Africa, Asia and Europe.
The project aims to study the wildlife and livestock populations in the Greater Serengeti ecosystem, how they interact with each other, and how the interaction of multiple susceptible species might contribute to persistence of PPR infection making disease control more challenging in a multi-host compared to a single host system.
Based on our previous studies we know that some common wildlife species can be infected with PPR virus, such as buffalo, wildebeest, gazelles and others. We do not know whether they are becoming infected by contact with sheep and goats, or whether the virus is circulating independently among wildlife.
The project will map the livestock and wildlife populations, their numbers, how they move and the type of contact between wildlife and livestock. It will measure the level of PPR infection in the wildlife by conducting a blood-sampling survey to test for PPR antibodies. It will measure the frequency of disease outbreaks in sheep and goat flocks as reported by farmers and through interviews with farmers and flock visits, in sites with different levels and patterns of livestock-wildlife contact. Putting all this information together, we will be able to plan the best way to carry out PPR vaccination in the sheep and goat population to eliminate infection in a short period of time, and the best way to carry out surveillance in both small stock and wildlife to monitor PPR infection and disease.
The project will be carried out by researchers from the Royal Veterinary College, University College London and CIRAD, France, working together with Kenyan and Tanzanian veterinary services, researchers and wildlife authorities and local institutions, and the local livestock keeping communities.
The valuable information gained from this study will be the first step towards eliminating PPR from this ecosystem and the lessons learned will be applicable in other parts of Africa and Asia. In addition to the new knowledge gained, reducing the impact of diseases like PPR will allow farmers, particularly women, in these areas to be more productive, to improve their food security and livelihoods. This comes at a critical time of transition to other livelihoods, with simmering tensions around land use, agriculture and biodiversity conservation, and the increasing effects of climate change and drought. Better disease control will allow people to be more resilient during this socio-economic transition.

Technical Summary

Peste des petits ruminants (PPR) is a transboundary viral disease of sheep and goats that is endemic in many countries of Africa and Asia, and is a major threat for pastoralist farmers, making a significant impact on food security, livelihoods and trade. PPR has recently been identified as a target for global eradication, but an important knowledge gap for the eradication effort is the role of wildlife in PPR epidemiology. The aim of this project is to improve understanding of the host-pathogen ecosystem of livestock, wildlife and PPR virus (PPRV) in the Greater Serengeti Ecosystem of Kenya and Tanzania to facilitate the design of effective and efficient surveillance and vaccination strategies for the elimination of PPRV. It is the first phase of a proposed five-year project that has the overall objective to test the hypothesis that the elimination of PPRV infection from domestic small ruminants leads to the elimination of PPRV infection from in-contact wildlife populations. The specific objectives are, in the Greater Serengeti Ecosystem; to define wildlife and small ruminant population spatial and temporal dynamics and their interface, to describe the spatial and temporal dynamics of PPR infection and disease in wildlife and domestic small ruminant populations, to develop surveillance and vaccination strategies for the elimination of PPRV from the ecosystem, and to strengthen coordination and build capacity to support cross-border disease surveillance and control policy and strategy. The project will develop a conceptual model of the ecosystem, integrate existing data and identify knowledge gaps to be addressed by qualitative and quantitative field studies in wildlife and livestock, including a serological survey to determine antibody prevalence in wildlife, strengthened disease reporting and investigation and active surveillance in livestock, and qualitative studies of small ruminant movements and trade, supported by laboratory diagnostics and molecular analysis.

Planned Impact

PPR is a disease of domestic sheep and goats and wild ruminants that is endemic across Asia and Africa, and in the past decade has expanded into southern and northern Africa, and central and eastern Asia. It causes high mortality in naïve populations (up to 100%), threatening food security, trade and biodiversity conservation, while in endemic areas there are frequent disease outbreaks that affect up to 50% of a flock causing high mortality, especially in young animals. Two thirds of sub-Saharan Africa are drylands where ruminant production is a central pillar of rural livelihoods and of particular importance to women, with small ruminants providing pathways out of poverty for pastoralists and agro-pastoralists. These are among the world's poorest people, commonly living on less than $1 per person per day. Their food security and future prospects are threatened by climate change and disease. Across sub-Saharan Africa there is a well-documented progressive species shift towards keeping small ruminants, linked to changes in climate, access to key resources and rising market demand. Controlling PPR can make a huge difference to the livelihoods of the poorest rural populations across sub-Saharan Africa and beyond. This project provides the foundation for demonstrating the elimination of PPR virus (PPRV) from a large complex multi-species wildlife-livestock ecosystem as pre-requisite for global eradication. It supports the first phase of a proposed five-year project by strengthening the necessary partnerships, improving understanding of the ecosystem, and developing surveillance and control methods and capacity. A key knowledge gap in global eradication centres on the role of wildlife in PPR epidemiology. If the proposed 5-year project is successful in eliminating PPRV from the ecosystem, it will demonstrate that wildlife is not a maintenance host for PPRV, and that elimination of PPRV from small ruminant populations will be sufficient to ensure eradication without intevention in wildlife populations. On the other hand, if the results show that wild animals are able to maintain PPRV infection, this will be crucial for initiating design of mitigation measures in these species. The role of wildlife in disease maintenance was a fundamental question during the rinderpest eradication programme: there was evidence that as incidence declined in cattle it also declined in wild animals in the Serengeti Ecosystem but with no systematic research the situation was uncertain even in the final stages of eradication. The results of this research will therefore provide evidence to support political will for eradication, increasing confidence of donors, Governments, communities and implementers in the global eradication process. This first phase will provide a case study of baseline data collection prior to embarking on PPR elimination; study design, qualitative and quantitative data collection methods, and data analysis. This will be relevant to extensive production systems in Africa and Asia, and will be disseminated through global PPR networks. It will provide useful information on other prevalent small ruminant diseases to support other disease control initiatives, and will strengthen communication between livestock keepers and veterinary authorities.
The project includes experienced skilled researchers in transboundary animal disease and virology (RVC, Pirbright, SUA), and draws on UCL anthropological expertise in local pastoralist systems. It will strengthen North researchers' collaboration with Africa and strengthen cross-border collaboration between veterinary services, wildlife and research organisations in Kenya and Tanzania, which will be extremely beneficial as PPR eradication efforts in Africa move forward. The PPR field test kit, developed by Pirbright Institute, will be used systematically as part of a surveillance system for real-time diagnosis which could accelerate elimination.

Publications

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Aguilar XF (2018) PPR virus threatens wildlife conservation. in Science (New York, N.Y.)

 
Description Mongolia FAO PPR strategy meeting
Geographic Reach Asia 
Policy Influence Type Gave evidence to a government review
Impact Provided evidence and advice on PPR outbreak in Mongolia and region in 2016 with focus on the wildlife spill over from livestock and failure of vaccination campaigns to halt this. Encouraged more cross disciplinary engagement between veterinary, wildlife and environment sectors as susceptibilities may relate to poor partitioning of land forage resources and mismanagement of shared resources. Multidisciplinary Government Task Force addressed organised under FAO and after CMC AH mission in early 2017 to outbreak zones.
 
Description GCRF Foundation Award
Amount £564,621 (GBP)
Funding ID BB/P023002/1 
Organisation Biotechnology and Biological Sciences Research Council (BBSRC) 
Sector Public
Country United Kingdom
Start 05/2018 
End 05/2019
 
Title ELISA Validation 
Description Provided data to progress validation of ELISA tests applied on PPR in a range of species. 
Type Of Material Antibody 
Year Produced 2018 
Provided To Others? No  
Impact Serology from wildlife is providing sufficient longitudinal data to question validity of applied ELISA tests developed for small ruminants. This is critical to eradication of PPR and its evaluation during the documentation on elimination. 
 
Description DVS Kenya 
Organisation Ministry of Agriculture, Livestock and Fisheries
Country Kenya 
Sector Public 
PI Contribution Support to fulfilling national strategy on PPR elimination
Collaborator Contribution Logistical support for field work and epidemiological data access from National surveillance.
Impact Project is starting implementation too early
Start Year 2017
 
Description DVS Tanzania 
Organisation Ministry of Livestock and Fisheries Development
Country Tanzania, United Republic of 
Sector Public 
PI Contribution Support to National strategy for control and elimination of PPR
Collaborator Contribution Logistical and access to data on PPR in country epidemiological support
Impact starting implementation phase
Start Year 2017
 
Description GCRF PPR 
Organisation Agricultural Research for Development (CIRAD)
Country France 
Sector Public 
PI Contribution Support to training of wildlife and livestock teams in PPR surveillance and research methods and support to fulfilling National strategies implementation in PPR control and elimination
Collaborator Contribution Logistics and staffing intellectual contributions to design
Impact Start of implementation phase
Start Year 2017
 
Description GCRF PPR 
Organisation Kenya Wildlife Service
Country Kenya 
Sector Private 
PI Contribution Support to training of wildlife and livestock teams in PPR surveillance and research methods and support to fulfilling National strategies implementation in PPR control and elimination
Collaborator Contribution Logistics and staffing intellectual contributions to design
Impact Start of implementation phase
Start Year 2017
 
Description GCRF PPR 
Organisation Ministry of Agriculture, Livestock and Fisheries
Country Kenya 
Sector Public 
PI Contribution Support to training of wildlife and livestock teams in PPR surveillance and research methods and support to fulfilling National strategies implementation in PPR control and elimination
Collaborator Contribution Logistics and staffing intellectual contributions to design
Impact Start of implementation phase
Start Year 2017
 
Description GCRF PPR 
Organisation Ministry of Livestock and Fisheries Development
Country Tanzania, United Republic of 
Sector Public 
PI Contribution Support to training of wildlife and livestock teams in PPR surveillance and research methods and support to fulfilling National strategies implementation in PPR control and elimination
Collaborator Contribution Logistics and staffing intellectual contributions to design
Impact Start of implementation phase
Start Year 2017
 
Description GCRF PPR 
Organisation Southern African Centre for Infectious Disease Surveillance
PI Contribution Support to training of wildlife and livestock teams in PPR surveillance and research methods and support to fulfilling National strategies implementation in PPR control and elimination
Collaborator Contribution Logistics and staffing intellectual contributions to design
Impact Start of implementation phase
Start Year 2017
 
Description GCRF PPR 
Organisation Tanzania Wildlife Research Institute
Country Tanzania, United Republic of 
Sector Public 
PI Contribution Support to training of wildlife and livestock teams in PPR surveillance and research methods and support to fulfilling National strategies implementation in PPR control and elimination
Collaborator Contribution Logistics and staffing intellectual contributions to design
Impact Start of implementation phase
Start Year 2017
 
Description KWS PPR 
Organisation Kenya Wildlife Service
Country Kenya 
Sector Private 
PI Contribution Training in epidemiological surveillance for PPR in wildlife
Collaborator Contribution Logistical and staffing support
Impact Starting implementation phase
Start Year 2013
 
Description Pirbright Institute 
Organisation The Pirbright Institute
Country United Kingdom 
Sector Academic/University 
PI Contribution Providing material of interest to PI investigations on viral diseases from Central Asia
Collaborator Contribution NGS on samples from Kazakhstan saiga mortalities to confirm viral absence or presence
Impact Confirmed absence of virus of potential concern to the massive die off of saiga antelope in Kazakhstan.
Start Year 2015
 
Description RVC-Pirbright _Biogene partnership 
Organisation BioGene
Country United Kingdom 
Sector Private 
PI Contribution Initiating an private public partnership on differential diagnosis methodologies around PPRv
Collaborator Contribution Providing the private capacity to develop potential diagnostic platform for PPR v and differentials.
Impact Satya and the company Biogene (BG Research Ltd) RVC submission to Innovate UK. The specific competition is Agritech catalyst early stage feasibility round 5, funding source the Technology Strategy Board, and title of project Pen side differential diagnosis of PPRV, FMDV and BTV from blood and swab samples
Start Year 2016
 
Description UAB - RVC - Daktari collaboration on bovine TB and sustainable livestock systems 
Organisation Autonomous University of Barcelona (UAB)
Department Faculty of Veterinary Medicine
Country Spain 
Sector Academic/University 
PI Contribution Information on TB from studies in wildlife and livestock in and around Queen Elizabeth National Park - helping implementation of veterinary support programme of UAB-Daktari NGO partnership. Opportunity for incorporating PPR studies into their portfolio of work from 2015. Obtained Partnership Grant
Collaborator Contribution Physical and Material support to our programme on Bovine TB in QENP. Physical Material and Data support to the BBSRC PPR research IUEPPR Support to development of proposals for H2020 funding on sustainable agriculture
Impact Improved knowledge of TB prevalence in wildlife and livestock in Western Uganda Akigera ecosystem. Data on PPR provided from livestock systems surrounding the QENP 2015, 2016, 2017 and further south during PPR outbreak in 2017. Provision of serum for serology on PPR.
Start Year 2013
 
Description Mongolia PPR Regional Strategy Meeting FAO 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Policymakers/politicians
Results and Impact Technical advisor to cross sectoral meeting on regional control of PPR organised by FAO in Ulan Bator Mongolia in light of PPR epidemic in Mongolia and China.
Year(s) Of Engagement Activity 2017
 
Description PPR Modelling workshop 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Study participants or study members
Results and Impact Workshop at Royal Vet College of Modellers to work on SEIR models for PPR with respect to wildlife serology results in IUEPPR project and outbreak data on PPR from Mongolia
Year(s) Of Engagement Activity 2017
 
Description PPR review lecture Utrecht FVM Tropical Medicine Course 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Postgraduate students
Results and Impact Lecture on PPR and seminar to present results from the IUEPPR project and status of PPR in wildlife
Year(s) Of Engagement Activity 2017
 
Description Programme Meeting Workshop IUEPPR Sweden 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Study participants or study members
Results and Impact Final workshop to discuss findings IUEPPR with wider programme present WP1 outcomes
Year(s) Of Engagement Activity 2017
 
Description Tanzania Wildlife Research Institute Annual Meeting Arusha 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Present results to audience of researchers engaged in East African region - summary of state of knowledge of PPR in wildlife in East Africa from IUEPPR project.
Year(s) Of Engagement Activity 2017