Periodic Reporting for period 4 - DEFEND (Addressing the dual emerging threats of African Swine Fever and Lumpy Skin Disease in Europe (DEFEND))
Reporting period: 2022-12-01 to 2023-11-30
DEFEND is an international partnership of academic, industrial and governmental organisations working together to tackle the emergence of African swine fever (ASF) and lumpy skin disease (LSD) in European livestock. Our overall objective is to control the growing ASF and LSD epidemics in Europe and neighbouring countries by understanding the drivers of ASFV and LSDV emergence, and generating research outputs which underpin novel diagnostic tools and vaccines, and authenticate appropriate and rapid responses by decision-makers.
African swine fever is an emerging disease that is currently spreading through pig populations in eastern Europe and Asia. The disease is caused by African swine fever virus (ASFV), is highly contagious, and causes a haemorrhagic syndrome which kills up to 100% of pigs in a herd. ASFV has caused the death of millions of pigs in Europe and Asia in recent years either directly or as a consequence of culling of infected herds. No vaccine exists to prevent disease, and control is heavily dependent on strict biosecurity measures.
Lumpy skin disease is an emerging disease of cattle. It is caused by the vector-borne poxvirus lumpy skin disease virus (LSDV). Since 2012 the virus has spread from the Middle East into new regions including Europe, Russia and Asia. An extensive regional vaccination campaign in south east Europe from 2016 - 2018 halted the spread of the disease further into central Europe, however it remains a threat to cattle populations worldwide.
DEFEND is designed around three scientific objectives:
• Objective 1. Identify the drivers for emergence of ASF and LSD in Europe
• Objective 2. Understand the fundamental biology of LSDV
• Objective 3. Develop tools for the management of ASF and LSD
DEFEND defined risk factors for the spread of ASF and LSD, developed a novel system to identify likely outbreaks along with a tool to assess the risk of an ASF outbreak in different types of pig farms. The project undertook an evidence-based analysis of the role of transboundary movements of people and animals in disease spread, as well as clarifying the role of biting flies in the transmission of LSD. These results can be used to support EU animal health and food policies through improved control of ASF and LSD.
African swine fever is an emerging disease that is currently spreading through pig populations in eastern Europe and Asia. The disease is caused by African swine fever virus (ASFV), is highly contagious, and causes a haemorrhagic syndrome which kills up to 100% of pigs in a herd. ASFV has caused the death of millions of pigs in Europe and Asia in recent years either directly or as a consequence of culling of infected herds. No vaccine exists to prevent disease, and control is heavily dependent on strict biosecurity measures.
Lumpy skin disease is an emerging disease of cattle. It is caused by the vector-borne poxvirus lumpy skin disease virus (LSDV). Since 2012 the virus has spread from the Middle East into new regions including Europe, Russia and Asia. An extensive regional vaccination campaign in south east Europe from 2016 - 2018 halted the spread of the disease further into central Europe, however it remains a threat to cattle populations worldwide.
DEFEND is designed around three scientific objectives:
• Objective 1. Identify the drivers for emergence of ASF and LSD in Europe
• Objective 2. Understand the fundamental biology of LSDV
• Objective 3. Develop tools for the management of ASF and LSD
DEFEND defined risk factors for the spread of ASF and LSD, developed a novel system to identify likely outbreaks along with a tool to assess the risk of an ASF outbreak in different types of pig farms. The project undertook an evidence-based analysis of the role of transboundary movements of people and animals in disease spread, as well as clarifying the role of biting flies in the transmission of LSD. These results can be used to support EU animal health and food policies through improved control of ASF and LSD.
Objective 1: Identify the drivers for emergence of ASF and LSD in Europe
• Potential disease risk factors were identified for ASF and LSD and a risk framework based on a novel participatory risk assessment system (PRMNAD) was developed to provide spatial indications of disease occurrence risk. The risk framework enables risk ranking and
mapping of potential disease occurrences, and aid in allocating valuable resources for transboundary animal disease control situations.
• Whole genome sequencing methodologies for LSD and ASF have been refined, and full genomes of LSDV isolates and ASFV isolates have been sequenced. Polymorphisms have been identified and used to better understand the spread of the viruses in the field, and to
review currently available molecular diagnostic methods.
• Fieldwork has been carried out in border regions of six countries and information was gathered on cross-border movements of people, live animals, and animal products as well as socio-economic factors and policy frames. Evidence-based recommendations to tackle the
spreading of animal disease in these regions have been formulated.
Objective 2: Understand the fundamental biology of LSDV
• A limited number of Stomoxys calcitrans flies are sufficient for transmission of LSDV from affected to naïve cattle. In addition, S. calcitrans flies can spread LSDV from subclinically infected cattle to naïve cattle
• LSD results in long term shedding of LSDV in semen. The presence of the virus in the semen is associated with very poor semen quality.
• LSDV survives some treatments of meat and skin products, with implications for export of animal products from LSDV-affected areas.
Objective 3: Develop tools for the management of ASF and LSD
• A decision tool for the evaluation of the risk of introducing ASFV into pig farms (both commerical and backyard) has been developed and evaluated.
• Mathematical models which simulate ASF in a wild boar population have been developed and used to identify the role of different factors on the progression on the disease.
• The immune response of cattle infected with LSDV has been characterised in detail. This information has been used to develop better tools for the serodiagnosis of LSD and design better vaccines.
• The serological response of cattle to LSDV vaccination has been characterised in detail, with particular focus on the impact of multiple vaccination doses.
Exploitation and dissemination
The results of the project have been disseminated and communicated via social media, the DEFEND website, scientific publications, and conference presentations. Outputs have also been directly disseminated to stakeholders and potential end-users such as policy makers and NGOs.
• Potential disease risk factors were identified for ASF and LSD and a risk framework based on a novel participatory risk assessment system (PRMNAD) was developed to provide spatial indications of disease occurrence risk. The risk framework enables risk ranking and
mapping of potential disease occurrences, and aid in allocating valuable resources for transboundary animal disease control situations.
• Whole genome sequencing methodologies for LSD and ASF have been refined, and full genomes of LSDV isolates and ASFV isolates have been sequenced. Polymorphisms have been identified and used to better understand the spread of the viruses in the field, and to
review currently available molecular diagnostic methods.
• Fieldwork has been carried out in border regions of six countries and information was gathered on cross-border movements of people, live animals, and animal products as well as socio-economic factors and policy frames. Evidence-based recommendations to tackle the
spreading of animal disease in these regions have been formulated.
Objective 2: Understand the fundamental biology of LSDV
• A limited number of Stomoxys calcitrans flies are sufficient for transmission of LSDV from affected to naïve cattle. In addition, S. calcitrans flies can spread LSDV from subclinically infected cattle to naïve cattle
• LSD results in long term shedding of LSDV in semen. The presence of the virus in the semen is associated with very poor semen quality.
• LSDV survives some treatments of meat and skin products, with implications for export of animal products from LSDV-affected areas.
Objective 3: Develop tools for the management of ASF and LSD
• A decision tool for the evaluation of the risk of introducing ASFV into pig farms (both commerical and backyard) has been developed and evaluated.
• Mathematical models which simulate ASF in a wild boar population have been developed and used to identify the role of different factors on the progression on the disease.
• The immune response of cattle infected with LSDV has been characterised in detail. This information has been used to develop better tools for the serodiagnosis of LSD and design better vaccines.
• The serological response of cattle to LSDV vaccination has been characterised in detail, with particular focus on the impact of multiple vaccination doses.
Exploitation and dissemination
The results of the project have been disseminated and communicated via social media, the DEFEND website, scientific publications, and conference presentations. Outputs have also been directly disseminated to stakeholders and potential end-users such as policy makers and NGOs.
The impact of DEFEND is being realised through implementation of innovative solutions for the control and prevention of ASF and LSD.
For example:
• A technical platform has been developed for a risk framework for low knowledge and high uncertainty disease spread situations
• Strategies for minimising transboundary animal disease spread in border regions and regions of unrest have been formulated
• Information has been gathered on the transmission of LSDV via arthropod vectors, fomites or via artificial insemination, to enable better control programmes to be designed.
• A decision tool for the evaluation of the risk of introducing ASFV into pig farms has been developed and trialled.
• Mathematical models which simulate ASF in a wild boar population have been developed and used to evaluate the impact of different surveillance strategies and to identify the role of different factors (such as hunting pressure, disease survivors, carcass removal) on the progression of the disease. The results of this modelling will be exploited by policy makers to design more effective strategies to reduce the spread of ASFV in wild boar and to reduce the spill-over of ASFV from wild boar to pigs.
Tools and knowledge such as these will support the European animal health policy motto “prevention is better than cure”. Potential impacts include a reduction in the economic losses suffered by the farming sector and improved food quality and security. These impacts will support EU animal health policies.
For example:
• A technical platform has been developed for a risk framework for low knowledge and high uncertainty disease spread situations
• Strategies for minimising transboundary animal disease spread in border regions and regions of unrest have been formulated
• Information has been gathered on the transmission of LSDV via arthropod vectors, fomites or via artificial insemination, to enable better control programmes to be designed.
• A decision tool for the evaluation of the risk of introducing ASFV into pig farms has been developed and trialled.
• Mathematical models which simulate ASF in a wild boar population have been developed and used to evaluate the impact of different surveillance strategies and to identify the role of different factors (such as hunting pressure, disease survivors, carcass removal) on the progression of the disease. The results of this modelling will be exploited by policy makers to design more effective strategies to reduce the spread of ASFV in wild boar and to reduce the spill-over of ASFV from wild boar to pigs.
Tools and knowledge such as these will support the European animal health policy motto “prevention is better than cure”. Potential impacts include a reduction in the economic losses suffered by the farming sector and improved food quality and security. These impacts will support EU animal health policies.