Research and analysis

Risk assessment on the likelihood of incursion of African swine fever to Great Britain from European Union Member States through human-mediated routes in June 2023 (executive summary)

Updated 20 January 2026

This summary outlines a qualitative risk assessment which has been completed to assess the risk of incursion of African swine fever (ASF) to Great Britain from European Union (EU) member states through human mediated routes.

The qualitative risk assessment on the likelihood of incursion of African swine fever to Great Britain from European Union Member States via human-mediated routes was updated in April 2022. This executive summary outlines a further update from June 2023.

Please note that this is the executive summary only. To request the full risk assessment, please contact ukassurance@defra.gov.uk. 

This updated risk assessment concluded that the:

• overall annual likelihood of entry is medium (event occurs regularly) with high uncertainty
• annual likelihood of exposure of a susceptible animal in Great Britain was considered low (event is rare but does occur) with medium uncertainty
• potential consequences of an ASF incursion in Great Britain were major with moderate uncertainty (major impact for small population, systems significantly compromised and abnormal operation, if at all, high level of monitoring required)

Background 

African swine fever virus (ASFV) is a highly pathogenic virus in domestic pigs and the Eurasian wild boar, with multiple cases identified across Europe in recent years.

ASF was introduced to new regions of Italy in January 2022 and reintroduced to the Czech Republic in December 2022. ASF was also reintroduced to Greece in January 2023 and was detected for the first time in Bosnia and Herzegovina and Croatia in June 2023.

In the past year (from 30 June 2023) European outbreaks of ASF in domestic pigs or wild boar or both have been reported in:

• Bosnia and Herzegovina
• Bulgaria
• Croatia
• Czech Republic
• Germany
• Greece
• Estonia
• Italy
• Latvia
• Lithuania
• Hungary
• Poland
• Romania
• Slovakia
• Moldova
• North Macedonia
• Russia
• Serbia
• Ukraine

The pathways considered in this assessment are:

• commercial trade in live animals
• commercial trade in products of animal origin (POAO)
• personal imports of POAO
• illegal imports of live animals
• passengers transporting fomites
• vehicles
• vectors
• animal feed, bedding and crops
• commercial trade in germplasm

Hazard 

African swine fever virus (ASFV) genotype II

Risk questions 

1. What is the annual likelihood of introduction of African swine fever virus from European member states into Great Britain?
2. What are the subsequent exposure routes to domestic or feral pigs and consequences to Great Britain?

Main findings

Entry pathways

This updated risk assessment concluded that the overall annual likelihood of entry of the virus into Great Britain is assessed as medium.

In particular, the individual route of personal imports of POAO was considered the highest risk pathway with a medium likelihood of occurring. A medium likelihood is defined as ‘the ASF virus may be regularly introduced into Great Britain’ over the next year.

The risk through commercial trade in live animals and their products, including germplasm and commercial POAO, as well as illegal imports of live animals, animal feed, bedding and crops was considered to be very low (event is rare but cannot be excluded).

Vehicle and passenger transporting fomites were concluded to be low (event is rare but does occur) risk and the risk of introduction by vectors was considered negligible (event is so rare that it does not merit to be considered). 

Exposure pathways  

Exposure to ASFV was assessed for 3 sectors:

• commercial pig farms with good biosecurity
• backyard, smallholder and pig farms with poor biosecurity
• free-living swine

While there is no trade in live animals from ASF-affected countries, the possibility remains that animals from newly infected areas where disease has not yet been detected could be imported. Therefore, the likelihood that pigs in Great Britain will be exposed to the virus through contact with infected live pigs is considered very low (low uncertainty) for all sectors. It was more likely that pigs in Great Britain were exposed to ASFV through imported POAO, or having contact with people or equipment which have come from ASF-affected areas and are contaminated with the virus.

The overall likelihood of exposure considering all entry pathways is low, defined as ‘an ASF outbreak is rare but does occur’ with backyard, smallholder and pig farms with poor biosecurity, and free-living swine the most at-risk populations.   

Consequence assessment 

The size of the impact is difficult to quantify and would depend on the outbreak size and duration. Given the welfare, trade, social, and economic impacts of an incursion, the consequence is considered to be major (moderate uncertainty).

The uncertainty is due to:

• the lack of previous ASF outbreaks in Great Britain
• differences between the pig sectors that may be affected
• the unknown trade partner agreements that may be implemented

Key uncertainties

Entry assessment

The key uncertainties in this section were:

• origin and quantity of POAO entering Great Britain as personal imports and the level of certification, traceability and biosecurity of the products and the premises of origin
• seasonal survival of the ASF virus in cold weather and environmental contamination in areas with high levels of infected wild boar where travellers may perform activities
• demonstrable spread of ASF outside restriction zone (RZ) boundaries, which means it is possible that imports arrive from newly infected areas before disease is detected

Exposure assessment  

The uncertainties in this section were the:

• variability in biosecurity measures on backyard, smallholder and pig farms with poor biosecurity
• extent of illegal swill feeding activities  

Consequence assessment

The uncertainties in this section were the:  

• size and duration of an ASF outbreak in Great Britain and the impact of different pig sectors
• length of time required to reach a regionalisation agreement to reinstate trade with the EU and third countries and the requirements of such agreements