Qualitative risk assessment

Transcription

1 Qualitative risk assessment What is the risk of introducing African swine fever to the UK pig population from European Member States via human-mediated routes? November 2018

2 Crown copyright 2018 You may re-use this information (excluding logos) free of charge in any format or medium, under the terms of the Open Government Licence v.3. To view this licence visit or This publication is available at Any enquiries regarding this publication should be sent to us at Exotic Disease Policy Team, Defra. 17 Smith Square, London SW1P 3JR PB

3 Contents Acknowledgements... 4 Summary... 4 Background... 5 Hazard identification... 6 Previous disease incursions into the EU:... 8 Current situation in the EU Risk question Risk assessment Terminology related to the assessed level of risk Uncertainty Entry assessment Exposure assessment Consequence assessment Final risk estimation Conclusions References... 31

4 Acknowledgements Expert opinion and peer review provided by APHA, Welsh Government, Scottish Government, DAERA, EPIC, The Pirbright Institute and feed manufacturers. Summary The situation with African swine fever (ASF) in the EU has deteriorated since June 2017 with several new geographic areas in Poland, Romania, Hungary, Czech Republic and Belgium reporting disease. These jumps (defined loosely as a new focus of infection at least 100km from the nearest wild boar case) are most likely to have been associated with human-mediated routes such as moving infected or contaminated meat products and leaving them in areas where wild boar can access them, or through the introduction into domestic pig farms with low biosecurity. The origin of these products is often unknown and therefore the source of infection is often only a suspicion. The ASF virus circulating in the EU and East Europe is still represented by genotype II, with little strain variation, and it is difficult to differentiate between the strains with limited sequencing. It is a highly pathogenic virus in domestic pigs and the Eurasian wild boar, but the rate of spread within herds is probably relatively slow (days to weeks) via direct contact with infected animals, their secretions or ingestion of contaminated feed, products or contact with contaminated surfaces. Therefore suspect cases may not be reported in a timely manner. The virus persists for long time periods in the environment and in fresh, frozen or preserved meats ( deli meats). Regionalization measures are laid down in Commission Implementing Decision 2014/709/EU. This Decision establishes animal health control measures on the movement and trade of pigs and certain pig products from the areas at risk of infection to limit the spread of ASF to other areas of the Union. Regions of affected Member States are listed in the Decision, based on their epidemiological situation and level of risk. In terms of risk of spread of ASF, movement of different porcine commodities poses different levels of risk. The Decision is aimed at avoiding unnecessary disturbance to trade within the EU and avoiding unjustified barriers to trade by third countries and the provisions that are set in this Decision are aligned with the OIE standard. Tracing meat products which are not commercially produced (homemade sausages and hams) is difficult in the European Union, where free movement of people and free circulation of products is one of the benefits of being in the EU. However, this means unless stricter controls are placed on the production of products, it will not be possible to

5 prevent further incursions into unaffected areas. The risk lies with the lack of certainty regards the size of the restriction zones and the effectiveness of the measures taken within. The constant changes in the status of different zones is evidenced by this and therefore meat products from these regions must be regarded with this in mind. The risk is therefore dependent on robustness of official controls. Therefore, the risk level for the entry of ASF into the UK has been increased to MEDIUM (i.e occurs regularly or LIKELY) with a medium level of uncertainty, which implies risk managers will need to consider more options for risk reduction. Background The recent spread of African swine fever into the EU from neighbouring countries in Europe has raised the issue of whether current control measures are sufficient to prevent the incursion of disease through human mediated routes into the UK. These routes do not include the natural movements of infected wild boar. African swine fever (ASF) is a disease of pigs, wild boar and other suidae and is endemic across Africa and, more recently, in parts of Europe. In 2007 the disease was first reported in Georgia, following introduction via international catering waste from maritime transport from Mozambique. The consequent scavenging by wild boar / feral pigs of the poorly disposed waste and slow diagnosis meant disease became established in the wild boar population, leading to outbreaks in the domestic pig population. The disease continued to spread across the Caucasus region, into Russia in 2007 from where it spread further. High levels of movement of people around conflict regions and the lack of biosecurity and controls for backyard pig populations (including poor compensation and lack of traceability, farmers selling pigs quickly to avoid being caught up in restrictions) led to further spread, establishment of disease and large geographic jumps. The disease was reported from many regions of Western Russia as well as Ukraine and Belarus in the intervening period and, in January 2014, the first cases in wild boar were reported from the EU, in Lithuania on the border with Belarus. ASF infection has now been reported in Estonia, Latvia, Lithuania and Poland since 2014, in the Czech Republic and Hungary in 2018 and in Romania and Bulgaria in summer 2018, and outside the EU, in Russia (including Kaliningrad), Ukraine, Moldova and China (first reported cases in 2018). The latest country to report disease (September 2018) in wild boar, is Belgium, another long geographic jump which is most likely to be human-mediated, taking contaminated products or equipment to an area where there is a high density of wild boar.

6 In 2010, EFSA published a scientific opinion which suggested there was a moderate risk of spread of ASF from the endemic regions in the Russian Federation and the Trans Caucasian countries through food waste or movement of wild boar into the EU (EFSA, 2010). There was considered to be a moderate likelihood of ASF becoming established in the EU in the wild boar and non-commercial low-biosecurity sector, low in the low-biosecurity commercial sector and negligible in the high-biosecurity commercial sector. The main risk routes are the use of swill feed in the low-biosecurity sector and contact with infected wild boar. It was highlighted that given the large low-biosecurity sector in much of Eastern Europe, the likelihood of further spread, once introduced, was high. EFSA provided a scientific opinion on the ASF situation in Eastern EU in 2014 (EFSA, 2014) which concluded that spread into neighbouring regions through movement of contaminated pork, infected pigs or contaminated vehicles was likely. The risk level, as determined by expert knowledge elicitation, for different matrices likely to be infected or contaminated and to maintain infectivity during transport ranged from very high for frozen meat to very low for crops and feed. Hazard identification The hazard is identified as: African swine fever virus African swine fever virus is a double stranded DNA virus of the Asfarviridae family which affects members of the suidae family, domestic pigs, wild boar and bush pigs. Several genotypes exist, and their virulence varies considerably. It is an arbovirus (ie it can be transmitted by arthropod vectors) and is highly resistant to environmental conditions, particularly to low temperatures. The virus was first introduced into Georgia in 2007 from East Africa in international catering waste (ship waste) at the port of Poti. It spread rapidly through the country had high virulence in domestic pigs and wild boar, leading to up to 100% case mortality. In terms of the standard epidemiological factors of transmission, virus is present in blood, faeces, saliva and urine; the average incubation period is between 5 and 15 days; diagnostic tests for the virus (PCR tests) can be positive after 3 days post infection, in experimental tests; pigs infected with genotype II are infectious for 4 to 10 days post infection; the latent period (time between being infected and becoming infectious) is around 2-6 days for some strains of ASF (Bellini et al, 2016; Guinat et al, 2014) or using inferences from mortality records of outbreaks in Russia, the mean latent period is 6-10 days, and sometimes as high as 13 days ( According to EFSA (2017) the basic reproductive rate for within pen transmission is 5.0 to 6.1 and between pens is 0.5 to 2.7 for the genotype II strain.

7 Therefore the rate of spread through a pig herd can take many days, unless all pigs are exposed at the same time, to the same source of virus. Early detection relies on testing every dead pig. Preventing spread relies on swift removal of any carcases. The virus is very resilient to environmental challenge. Estimates of (maximum) virus survival time (time after which viable virus can still be isolated from the product) in various products of porcine origin are shown here (summarised by Adkin et al., 2004): Product Survival Time (days) Product Survival Time (days) De-boned meat 105 Smoked de-boned meat 30 Meat bone-in 105 Frozen meat 1000 Ground meat 105 Offal 105 Salted de-boned meat 182 Skin/fat 300 Cooked de-boned meat 0 Speciality ham (Serrano) 140 Canned meat 0 (Parma) 183 Dried meat bone-in 300 (Iberian) 140 Estimates of virus survival in other conditions are given here (summarised by EFSA, 2010; DWHC, 2014): Condition Survival Time Condition Survival Time Temperature at 50 o C 3 hours Putrefied blood and bone marrow 15 weeks Temperature at 56 o C 70 mins Faeces (room temp) 11 days Temperature at 60 o C 20 mins Slurry at 65 o C 1 month <ph4 or >ph11.5 minutes Contaminated pig pens 1 month Blood stored at 4 o C 18 months Survival in air 20 mins half life

8 The strain which has been isolated in the East European outbreaks is Genotype II and is not the same as that found on the Iberian Peninsula in the s outbreaks (and which is still present in Sardinia). That particular strain has relatively low pathogenicity and leads to persistent infection in some recovered pigs for up to 30 days or even longer (EFSA, 2010). Neutralising antibodies do not eliminate disease, therefore seropositive animals may still be virus carriers. There is no vaccine available. The strain circulating in East Europe is a relatively new incursion (from 2007) into a naïve population and is showing a high degree of virulence. Nevertheless, some experimental evidence suggests that the virus is starting to become moderately pathogenic in pigs, as occasionally pigs will survive to develop antibodies (see the Community Veterinary Emergency Team report from Lithuania, sf_lithuania_cvet_en.pdf). Transmission routes most commonly involve direct contact with infected pigs or wild boar, either oral, nasal, subcutaneous or ocular or through consumption of contaminated products such as infected meat. The infectious dose in products is low, while aerosol transmission is less likely. For indirect transmission (contact with people, vehicles and fomites), a larger virus load is required than for direct transmission (such as blood transmission); transmission is less efficient with the lower pathogenicity strains, due to strain variation (EFSA, 2010). There are still questions surrounding the role of biting flies in mechanical transmission of ASF over short distances, while the soft bodied ticks are responsible for persistence of infection in some areas (including the Iberian Peninsula) and are less likely to be involved in long distance movement of infection. It is not known whether ticks endemic in Eastern Europe/Russia can transmit ASFV. Transmission through contaminated water has been suggested although not demonstrated epidemiologically. Transmission through water is feasible from a risk assessment perspective, because although dilution of the virus in the river water reduces the exposure to pigs drinking the water, it does not eliminate the risk if there is no threshold dose. Thus dispersion of the virus does not significantly reduce the overall probability of infection. Previous disease incursions into the EU: International catering waste has been the cause of ASF incursions into the EU to Portugal in 1957, Malta in 1978 and Sardinia in However, there have been no incursions of ASF into the EU via this pathway since the EU swill-feeding ban in 2001.

9 Country of outbreak Year Likely source of infection Origin of disease Portugal 1957 Raw pork waste at airport Angola Spain 1960 Swill feeding Portugal Portugal 1960 Pork meat France 1964? Spain Italy* 1967? Iberian peninsula Malta* 1978 Raw pork waste at airport Iberian peninsula Spain 1971 Food waste animal feed Cuba Sardinia 1978 Raw pork waste at airport Iberian peninsula Belgium 1985 Pork meat and swill feeding Spain Netherlands* 1985 Illegal swill feeding catering waste Iberian peninsula Italy 1969 Spain 1978 International catering waste Brazil Italy* 1983 Iberian peninsula Spain 1992 Vectors Georgia 2007 Ships catering waste Mozambique Lithuania 2014 Wild boar movements Belarus Romania 2017 Spread due to mating / insemination for limited premises Czech Republic 2017 Imported Ukrainian salo pork fat Ukraine China 2018 Unknown source possibly wild boar and undetected spread in backyards Belgium 2018 Unknown source possibly discarded contaminated products * The strain involved was only moderate pathogenicity Eastern Europe Russia most likely East Europe Under EU Legislation, ASF controls include a ban on the movement of wild boar, domestic pigs and products of animal origin, including germplasm (2002/60/EC). Products of animal origin for human consumption can be processed, according to Directive 2002/99/EC Annex III treatments.

10 Current situation in the EU In the EU during 2017, there were 123 outbreaks in domestic pigs and 3,867 in wild boar reported to the ADNS system. In 2018 (to September) there were 167 outbreaks in pigs in the same countries (PL, EE, LV, LT, CZ and HU) and 3,976 in wild boar. A slight increase in the 2017 numbers, but nothing significant. New areas in central and northern Poland on the border with the Russian exclave of Kaliningrad are the sources of these additional cases (highlighted in the maps below). However, Romania first started to report cases in the southern region of Tulcea in May 2018 and the number of domestic pig cases has now reached over 1,200 (mainly backyard but including some large commercial farms), which is 9 fold more than the other affected countries combined. In addition, a recent incursion into Belgium in two wild boar was reported in September, which again represents another large geographic jump. Although the source has not yet been confirmed, the most likely cause is via human-mediated routes. Previous outbreaks in Romania in 2017 were on the Northern border with Hungary / Ukraine and although the index case source was not reported, the second case was through a boar being moved to the farm for mating/insemination purposes (EFSA, 2017). Figure 1: Map of the outbreaks in Europe during 2018

11 The following two graphs (Figure 2a and 2b) show the month by month cases in wild boar and pigs across the EU from January 2017 to 15 th September It appears there are two situations evolving. In northeast EU, wild boar are the most commonly detected cases, with few sporadic incursions into domestic pig establishments although occasional jumps in geographic distribution into discrete areas, most likely caused by human-mediated routes. In contrast, in Romania, there is a substantial number of outbreaks occurring in domestic pigs and only a few cases in comparison in wild boar (which may be due to poor surveillance). The most recent EU Veterinary Emergency Team mission identified an initial epidemic wave of infected wild boar from Ukraine across the Danube as the most likely source of infection, followed by an unprecedented epidemic in pigs reared in non-professional holdings; exacerbated by poor biosecurity, delays in pre-emptive culling where no compensation is available unless establishments have a positive laboratory sample. In July 2018, a large commercial establishment of ~43,800 pigs was identified as infected, with a likely infection date of the 24 th May The source of infection is unknown. This slow progression of infection in a large herd is not unusual. A similar situation has been observed in other commercial farms and in experimental infections (CFSPH, 2015). For further information see the EUVET presentation at Figure 3 shows the most recent EU Restriction Zones in place. Figure 2a Number of cases in wild boar in the EU in

12 Figure 2b Number of outbreaks in domestic pigs in the EU in

13 Figure 3: 2014/709/EU Annex parts I, II and III: requirements for controls and derogations allowed. Annex part IV only covers Sardinia where disease is endemic.

14 Figure 4: Schematic simplified version of the restrictions in place in each area of the Annex.

15 On the first notification of disease in the EU, new legislation came into force, in which different areas of affected countries are listed, according to the level of disease reported (2014/178/EU and then 2014/709/EU). For a simplified explanation of these rules, see Figure 4. Part IV is only relevant for the island of Sardinia as an area where ASF is present, endemic and stable. The regions in the restriction areas are updated regularly at the meetings of the EU Standing Committee for Plants, Animals, Food and Feed. The latest update is in the following map. Details can be found at Under this Decision, the area falling within Part I of the Annex is where disease has not been reported, but there is a risk of disease introduction through proximity to a wild boar case. Live pigs may still leave this region for trade purposes, provided they fulfil certain conditions for testing negative for disease. Feral pigs (such as wild boar) may only be consigned for trade if they fulfil requirements including residency at an approved establishment for 30 days. This has now been revised to prohibit the movements from any area listed in the annex to other parts of the same MS. Unprocessed or untreated pig meat and pig products may still be dispatched for intracommunity trade; wild boar meat and products may also be dispatched, provided the meat is marked and the animals have previously tested negative for ASF. In April 2018, the European Commission reminded Member States that the trade of wild boar (apart from those originating in an approved establishment) from one MS to another is not allowed. ( As the disease has continued to spread, so these restriction areas have been increased in size to compensate (see Figure 3). However, there continue to be large geographic jumps which cannot be explained by the natural movement of wild boar. This raises the concern that the controls are not sufficient to prevent spread of disease in countries with a high number of backyard pig herds, where biosecurity is poor or if there are people travelling with contaminated or infected products which are abandoned in areas where wild boar live (Guinat et al, 2016). The controls applied in Part I regions will limit the movement of live pigs to other member states, and of live pigs from Part II and Part III into Part I, but not for fresh / frozen meat and therefore these restrictions rely on the boundaries being in the right place. These zones are regularly changing as the disease continues to spread and jump into new establishments.

16 Risk question The specific risk question addressed is: What is the risk of introducing African swine fever virus from European Member States through legal and illegal trade, transport or other transmission routes into the UK and subsequent exposure to domestic or feral pigs? To answer the above question, the risk assessment follows the OIE framework of release (or entry), exposure and consequence assessment. Specifically, it is divided into three key areas: Legal trade in live animals and products of animal origin; Illegal trade in live animals or products of animal origin; Fomite transmission, transport or other identified routes. Risk assessment Terminology related to the assessed level of risk For the purpose of the risk assessment, the following terminology will apply (OIE, 2004; EFSA, 2006): Negligible Very low Low Medium High Very high So rare that it does not merit to be considered Very rare but cannot be excluded Rare but does occur Occurs regularly Occurs very often Events occur almost certainly For the purpose of risk management purposes, we have also included a new system. Probability terms and subjective probability ranges are used to describe the steps of the risk pathways (EFSA, 2016a). This system may be used where probabilities have been defined for certain steps in the pathways and is not expected to imply precision.

17 Probability term Subjective probability range Negligible Indistinguishable from 0 Extremely unlikely 1% Very unlikely > 1% 2% Unlikely > 2% 10% Likely > 10% 100% Likely is used as a general term when risk managers would need to consider whether it is possible to mitigate any step which has a greater than 10% probability of occurring. It is assumed that most risk managers will not distinguish between 10% and 100% likelihood; anything within this range will be managed. This reduces the levels of complexity in terms of assessing the risk, but it can lead to large boundaries of subjectivity where probability of occurrence of the likely risk level is anything between 10% and 100%.Risk managers may still choose to act on any level below 10% and indeed, low or unlikely may be the threshold in certain circumstances. Uncertainty Ratings used to describe the level of uncertainty (agreed by the EFSA AHAW Panel in 2015) Name Low Moderate High Explanation No or limited information or data are lacking, incomplete, inconsistent or conflicting. No subjective judgement is introduced. No unpublished data are used. Some information or data are lacking, incomplete, inconsistent or conflicting. Subjective judgement is introduced with supporting evidence. Unpublished data are sometimes used. The majority of information or data are lacking, incomplete, inconsistent or conflicting. Subjective judgement may be introduced without supporting evidence. Unpublished data are frequently used.

18 Entry assessment Legal trade in Live Animals Live pigs are approved for trade between EU Member States in accordance with 64/432/EEC (as amended) requiring animals to come from a holding and area which are not under restriction for any notifiable disease of swine (including ASF) and requiring veterinary certification. The control measures applied under 2002/60/EC allow derogations for the movement of live pigs out of an ASF restriction zone, following a veterinary risk assessment and additional controls, such as negative PCR testing at the individual level; however, the movement would not be allowed to another Member State, and this is only applied to pigs destined for slaughter. Under 2014/178/EU and 2014/709/EC further control zones are applied in the event of an ASF outbreak or case being reported, which again allow the movement of live pigs as a derogation, according to Figure 4. No live pigs have been dispatched to the UK from affected regions or countries for more than one year and, generally, the level of trade from these regions is very low (see table below). Other suidae which may be dispatched for trade include exotic pig species or captive wild boar destined for approved premises such as zoos or exhibitions, but again these are subject to disease control measures under 92/65/EEC. Such moves are rare and, in the UK, involve non-domestic ( exotic ) pig species moved between approved premises for captive breeding programmes. Pet pigs are not considered by definition pets, but are still considered livestock and should still be subject to 64/432 certification. Wild boar or feral pigs (the definition is those pigs which are not raised in a holding or under control of an operator) may not be dispatched for trade. Therefore, given there has been no recent direct trade in live animals from the affected regions of Bulgaria, Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, and Romania, and given the certification requirements for the disease free status of live pigs and clinical examination prior to travel, this pathway is considered to be an annual probability of negligible (low uncertainty). This also applies to the latest cases in wild boar in Belgium. Number of pigs imported into the UK from EU member states

19 Austria Belgium Germany Denmark 1, ,630 2,244 1,948 1,442 France Ireland 715, , , , , , ,081 Netherlands Sweden Total 717, , , , , , ,769 Legal trade in Products of Animal Origin In Part I regions, only the meat of feral pigs / wild boar is prohibited (unless the animals are tested and the meat is marked and it is only destined for dispatch to within the same MS), otherwise all fresh and frozen meat and untreated products may still go to intracommunity trade. In Part II regions, fresh meat of domestic pigs may also be dispatched to other MS provided the pigs originated in areas outside Parts III or IV. In Parts III and IV regions, fresh and frozen pig meat and products of porcine origin must be produced for dispatch onto the EU market in accordance with certain measures: domestic pig origin meat or products must test negative for ASF or show 30 day residency and on farm biosecurity requirements, be health marked and only be dispatched with a veterinary health certificate; all domestic pig origin meat and products must be processed (heat treatment), marked and be dispatched with a veterinary health certificate. There are also derogations to allow the movement of animals for immediate slaughter from Part III to approved slaughter houses in other areas, provided the pigs have tested negative and been resident for 30 days. All told, there are complicated requirements for various pig products, fresh and frozen pig meat for all the Parts regions, and depending on the approval of slaughter houses and cutting plants. We consider this pathway, provided there is a stable disease situation in the area and all the correct biosecurity measures are in place, to be an annual probability of extremely unlikely (moderate uncertainty). This is because according to TRACES, there are very few consignments to the UK from these areas and the risk level can apply to other countries with a low volume of trade and restriction zones in place. Where the situation is still evolving (eg in Romania) the risk level will be as below. Where there are high volumes of product entering the UK, the risk level may increase, hence the moderate uncertainty.

20 Legal trade of pig meat from Romania Under Implementing Decision 2013/764/EC, all fresh and frozen pig meat and certain products from pigs should be accompanied by an intra-union trade health certificate and notified in TRACES, the EU trade notification system. There are additional requirements on the biosecurity of the place of origin and the disease situation with reference to classical swine fever. In July, a slaughter house in Romania detected a single animal entering for slaughter that showed clinical signs and subsequently tested positive. The UK was notified by the Romanian authorities that a consignment produced during the high risk window (May 24 th onwards) at the slaughter house had been consigned to the UK. This consignment was destroyed. Subsequently, several consignments of frozen pig meat arrived to the UK from Romania from a different company and different slaughter house, which were notified to TRACES. These were followed up on arrival in the UK with the importing company and it was apparent that the products were derived from farms across the whole territory of Romania, including some regions which subsequently came under Part III restriction. It was estimated some 23,000 pigs would have been the origin of the products (frozen pork ribs). There was information provided by the company on limited (voluntary) testing of some pigs undertaken in July but this was to detect a level of 10% prevalence in three farms, which is not sufficient for an early warning system in several large pig herds. The consignments were destroyed on the basis of a risk assessment and with agreement of the importer. In the last quarter (July to September), there have also been over 500 consignments of more than 700 tonnes of [commodity code for] sausages and similar products, of meat, meat offal or blood, food preparations. Some of these are from pigs which were slaughtered in Denmark and then moved to cutting plants and cold storage in Romania, and several consignments are from local veterinary units which are now within Part III restrictions. It is not clear from the certificates if the produce has been treated, as some of the certificates provide guarantees in line with 2013/764/EC (no treatment) and some for 2014/709/EC (treatments include heat treatment to Fo of 3.00, treatment to 80 o C throughout, heating in a sealed container to 60oC for 4 hours, natural fermentation and maturation for nine months to ph 6.0 or natural fermentation for hams and loins for 160 or 140 days resp. all in accordance with 2002/99/EC). Therefore, considering the slow moving nature of ASF within a pig herd, the unstable epidemic situation in Romania and the very low level of (voluntary) testing of herds of origin, the probability of meat from at least one infected pig being present in consignments of fresh or frozen pig meat or untreated products of pig origin is considered to be likely (low uncertainty). In addition, because of the lack of treatment

21 for certain deli meats and uncertainty around whether it would completely mitigate the presence of ASFV, we would assign a similar level to these products. Salo or Szalonna: this pig product was suggested to be the source of infection of the wild boar cases in the Czech Republic. Salo is a delicacy in Eastern Europe and consists of unrendered pig fat, seasoned with salt, pepper, paprika or other spices and eaten as small cubes. Sometimes there is a layer of skin or meat still attached. It may be smoked or aged as well. Illegal trade in Live Animals The illegal movement of live pigs, live wild boar or live pet pigs from continental Europe to the UK cannot entirely be ruled out but is believed to be extremely unlikely (moderate uncertainty). Illegal trade in Products of Animal Origin (POAO) As the risk question relates to the movement of products within the EU, the illegal products concerned would be those produced in Parts II, III or IV regions and not treated sufficiently to mitigate the presence of ASF virus. These are most likely to be derived from non-commercial farms. Therefore, the probability of people arriving in the UK with such products is considered likely (moderate uncertainty). Passengers, visitors, workers and hunters The ASF virus can be carried on clothing and on footwear that has not been cleansed and disinfected. The virus can persist for several days particularly if protected by organic matter (Bellini et al. 2016). Therefore, anyone with contact with an infected area, such as walkers, hunters, and farm workers visiting/returning to the UK could, in theory, carry contamination with them. The EU has recognised the risk posed by hunters of wild boar who visit a contaminated area and we are aware of some travel companies offering organised hunting trips to parts of Poland in the East which are currently affected with ASF. This is difficult to quantify. However, given the large numbers of persons in terms of walkers, hunters, farm workers returning to the UK each week we consider there is at least a 10% chance of at least one of these people having contaminated clothing,

22 footwear or equipment per year to the UK through this route and it is overall likely (high uncertainty). Vehicles Entry to the UK from mainland Europe for road vehicles is via either a ferry or the channel tunnel. These routes do not provide a direct link to a country with a high level of infection. There has been a significant rise in road vehicles registered in Eastern Europe travelling though UK ports in the past decade. Road vehicles registered in Poland now account for 20% (415,000) of all commercial vehicles travelling though UK ports from Mainland Europe each year as opposed to 3% (58,000) ten years ago. Road haulage vehicles from Poland lift the highest tonnage of goods to the UK at over 11 million tonnes in Romanian haulage vehicles account for over 3 million tonnes, which is the third ranked country for foreign vehicles (data supplied by DfT International Road Freight statistics for 2017). There are no accessible data for private vehicles, nevertheless we would expect the number to have increased in a similar fashion. The main source of infection is within the backyard pigs and wild boar populations in Eastern Europe which means that the virus could be present in the environment and fomite transfer can happen via any vehicle that has travelled within the infected area. There is no requirement for private vehicles to be cleansed and disinfected before entry into the UK. However, the long distance and time (over 20 hours) of driving between London and Eastern Poland and Baltic States where the disease is present will offer some degree of mitigation of the risk, but it would depend on the level of contamination and the lack of cleansing and disinfection carried out. Vehicles that have been in contact with backyard pig farms and used for hunting pose a greater risk, as these vehicles could have been in contact with swine or used for transporting swine. It is unknown how many vehicles from the UK travel to the region for the purpose of hunting or visiting backyard pig farms and given the recent cases in Belgium and the volume of traffic which could enter the UK the risk level is considered to have increased to likely (moderate uncertainty). Commercial Livestock Vehicles There is only limited trade in livestock from the affected regions. However, there is no information on the number of vehicles that have moved livestock to and from the affected countries which could have been used to transport products other than livestock to the UK. Only livestock vehicles are required to be cleansed and disinfected before entering a commercial pig farm. Other vehicles could have been used to transport other products within an infected area and become contaminated. In addition,

23 the experience of the USA during recent outbreaks of Porcine Epidemic Diarrhoea show that drivers of livestock vehicles have been identified as a possible risk pathway. Whether these livestock vehicles are sufficiently cleaned and disinfected maybe uncertain. On-going EPIC work suggests that transportation vehicles have higher potential to spread the disease than live animal movement, because livestock vehicles are insufficiently cleaned and disinfected. Therefore, given the EU rules about cleansing and disinfection of livestock vehicles, this is considered unlikely (high uncertainty). The uncertainty is related to the seasonal survival of the ASF virus in cold weather and environmental contamination in areas with high levels of infected wild boar. Other passenger vehicles from Europe No information about the risk pathway is available on passenger vehicles (commercial vehicles, such as buses and coaches), but this is thought to be very unlikely (high uncertainty) as there is little access to high biosecurity commercial pig premises in the EU, but they may pass through an area where wild boar are infected and therefore with high environmental contamination. Shipping and other maritime transport There are several types of maritime transport which could originate in the affected areas: tourist cruise ships; commercial ships with cargo; private shipping. Of these, the crew and passengers may carry illegal POAO, vehicles may be contaminated with virus and catering waste may contain contaminated pig meat. This pathway is considered to be likely, but with high uncertainty and is related to the fact that lack of checks done for catering waste from the EU or for contamination of containers. International Catering Waste International Catering Waste (ICW) from outside the EU is treated as a Category 1 Animal By-Product under Article 16 of Directive 97/78/EC. Further legislation (Directive 001/812/EC and Regulation 1774/2002/EC) requires the waste is disposed of correctly and that appropriate records are kept. However, such provisions only apply to catering waste (including consumption by cabin crew and passengers) for international (ie outside the EU) transport. For transport within the EU, such waste is treated as category 2 ABP which requires a low level of disposal. There are no category 2 level ABP plants in the UK and therefore all waste should be disposed of as category 1. The pathway is considered very unlikely (moderate uncertainty).

24 Biting flies and ticks The soft bodied or Argasid ticks, such as Ornithodorus spp. are most commonly cited as the mechanical vector for ASF; in Europe and the Mediterranean basin, O.erraticus is the main species. No Argasid ticks exist in the UK on livestock or wildlife and the climate is not suitable for establishment. It is possible that live animals may carry such ticks to the UK, but this is generally considered to have a low likelihood for long distance spread as ticks feed for very short periods and then drop off the host to look for another. It is therefore discounted as a risk pathway for introducing disease to the UK. Biting flies, such as Stomoxys calcitrans, the stable fly, have been shown experimentally capable of maintaining viable ASF virus in mouth parts after feeding on an infected pig, for up to two days (Mellor et al. 1987). The virus titre remained constant in the flies although volume of infected blood taken up varied considerably. When flies were part fed on infected blood then allowed to continue to feed on an uninfected animal one hour and 24 hours later, the pigs developed clinical signs typical of ASF infection (Mellor et al, 1987). Stomoxys are generally feeding on cattle or horses and can transmit such pathogens as Equine Infectious Anaemia virus, but will also feed from other livestock or humans. They frequently fly up to 1.5 km a day and for this reason represent less of a risk for long distance spread, but more so for local spread (Kaufman and Weeks, 2012). There is a high level of uncertainty around the impact of vectors in the transmission of ASF. A recent paper looking at the role of biting flies in Lumpy Skin Disease incursion into France (Saegerman et al, 2018) suggested the movement in trucks of stable flies, Stomoxys calcitrans, is possible, more so than Tabanid flies which don t survive long journeys as they are rapidly damaged and die from trying to get out of the truck. There are several steps in the pathway which are also seasonally dependent: the insects must bite an infected animal prior to entering the truck or an infected animal should be in the truck; the journey time must be shorter than the viral survival; the animals are not unloaded during the journey (for journeys shorter than 8 hours) the truck enters a farm where there are susceptible animals; the flies bite a naïve animal and transmit an infectious dose. But if the journey time is longer than the virus survival time, then unless the animals in the truck are infected, this is considered to be a very low probability (high uncertainty) reducing to negligible in the winter months. This risk level realistically would only apply to live animals coming from Belgium, as the rest of Eastern Europe would be too long in journey time and therefore the probability of entry would be Negligible. Crops, seeds and feed Although the EFSA opinion of 2010 considered crops and hay to be negligible risk, new information on contaminated crops being fed to pigs in NE EU suggests this is a

25 credible risk pathway (Bellini et al., 2016). Expert opinion was sought from feed producers. One area of interest is the imports for feed during periods of poor forage availability. Grain crops: There is anecdotal evidence of grain and forage being imported from Ukraine over the summer, but these should be processed into pig feed, not fed raw however that processing does not include heat treatment. Compound pig feed prices increased between 2016 and 2017 and the use of crops as biofuel commanding a higher price than for animal feed may push cheaper imports and it may not be possible to ascertain whether these are coming from areas with high environmental contamination with ASFV. Nevertheless, there is only limited evidence to suggest this is a credible risk pathway. In the Baltic States, some backyard farms became infected as a result of feeding pigs on grass where wild boar had been found dead, therefore the grass and hay was understood to be contaminated. Wild boar will preferentially spend time in crop fields and therefore if they are infected and die in situ and not disposed of, the environmental contamination may contribute to transmission. At present therefore this cannot be ruled out. Use of blood or plasma in feed: Pig herds which are part of the pig assurance scheme (which covers 92% of the England pig population) should only be fed purchased compound feed or feed materials from assured compounders or merchants and must only use those, which are permitted under UK and EU law. Blood products for animal feed are approved of for import into the EU, but have only very limited use in the UK pig market currently and are not allowed under Red Tractor Farm Assurance scheme for UK pig farms (Red Tractor Assurance, 2013). The production of such feed would require operators to process the blood to standards that reduce the risk from hazards (including pathogens) to levels that provide an insignificant risk to public and animal health; in effect these measures include heat treatment and spray drying. However there remains uncertainty about the effectiveness of such treatment particularly for a virus such as ASFV, therefore this remains a credible pathway although the UK pig sector should not be using it. Use of soybean as animal feed is very common and certain methods may involve extracting using solvent, using mechanical processes on dry flakes or using screw pressing with steam. Although it is not clear whether there could be some contamination of the product with ASFV, the majority of soya imports to the EU are from South and North America, not Eastern Europe (or China). Other feed additives such as vitamins and minerals (chondroitin or glucosamine, vitamin D etc) may be of animal origin but would be subject to an extraction process expected to mitigate any viral contamination.

26 Raw pet food: for European trade, all raw pet food should only be made from category 3 animal by-products, or category 1 where an illegal treatment has been used. Therefore if, for example, someone were to feed a dog some pork bones as raw pet food, and these were accessible by feral pigs or domestic pigs, this should still be a negligible pathway provided the animal by-product rules are adhered to. Considering the variety of feeds imported to the UK and their origins and processing, this pathway is considered to be very unlikely with moderate uncertainty. [Information on feed processing can be found at Bedding The source of bedding could be a theoretical pathway if straw or wood chips were imported from an affected area. Expert opinion about the survival of ASFV on wood suggests it is possible, but would depend on the faecal or blood contamination of the pallet which is then made into chips, but anything that has had contact with infected pigs should be thoroughly cleansed and disinfected as part of the disease control measures under EU rules. Therefore this pathway is considered to be very unlikely with moderate uncertainty. Exposure assessment For the purposes of this document we consider the exposure of all pathways to each of the three sectors (feral pigs, backyard (smallholders) and commercial pigs) in a single entry, given the most likely pathway is feeding animals infected meat or having contact with people who have come from affected areas. Usually, the term wild boar refers to where these animals are native and endemic to the region, while the term feral pig refers to the invasive populations of introduced wild boar, such as those present in the UK. The natural movement of wild boar is not a risk pathway into the UK at present. Legal movements of live pigs are considered a negligible probability. Swill feeding is the most likely pathway for ASF virus to enter a pig farm in the UK, although feral pig contact with non-commercial pig farms cannot be ruled out. Swill feeding is not allowed in the UK or EU and this includes feeding feral pigs with food. Nevertheless, there may be some swill feeding which is carried out in backyard premises or inadvertent disposal of products in an area with free range pigs or feral pigs, and indeed anecdotal information of pigs in pannage in the New Forest in southern

27 England suggests they have had access to commercially produced (albeit cooked) sausages. Therefore, the exposure to the UK pig population cannot be ruled out. Commercial pig farms In general, the majority of the UK commercial pig sector is part of the Red Tractor Assurance scheme and has good biosecurity in comparison to non-commercial sectors. Although there is likely to be a considerable number of low biosecurity backyard pig farms in the UK, their contact with the commercial, high biosecurity sector is minimal and therefore the risk of spread from low to high biosecurity premises would be extremely unlikely (moderate uncertainty). There are trade exchanges between small producers and commercial farms, particularly the more family-owned businesses side of the sector (e.g. those that process their own meat for local markets). Importing live pigs into a farm is not the only pathway for disease incursion; animal and feed transport vehicles could be shared, equipment may be shared and of course, there could be contact between one farm and another or with feral pigs. Thibaud et al (2016 and 2014) modelled the spread of swine fever based on registered movements between premises and their work suggested that non-assured premises (that is, small commercial premises with fewer than ten breeding animals) may provide a bridge between small holders and large commercial premises and as surveillance is less targeted at these type of farms, the time to detection of disease may be extended. There is no information available on the nationality of people working on pig farms, despite the anecdotal evidence of Eastern European citizens being employed in large numbers in such businesses. According to the Office for National Statistics data on the nationalities of the population living in the UK ( ationalmigration/datasets/populationoftheunitedkingdombycountryofbirthandnationalityu nderlyingdatasheets) there are estimated to be 390,000 people from Romania, 922,000 people from Poland, 31,000 from Ukraine and 59,000 from Russia. However, the high biosecurity premises require workers to have a period of days (usually at least 3 days) when they cannot go back to work after travelling or having contact with other pigs, and that clothing and shoes must be changed before entering a premises. This pathway is considered very unlikely (high uncertainty) given the high awareness of commercial pig keepers in the UK following the communications campaigns currently running.

28 Non-commercial and low biosecurity pig farms Survival of virus in certain products means there is a credible risk pathway into UK pig farms should swill feeding (from deliberate feeding of catering and food waste, to the accidental disposal of contaminated food near a pig farm) take place and dependent on the product itself being brought into the UK. But given the number of people travelling from Eastern Europe and potentially bringing back contaminated products, this is a likely probability (high uncertainty) for exposure to non-commercial and low biosecurity pig farms. Wild boar / feral pigs There are several discrete populations of unmanaged wild boar in the UK, the most substantial one is in the Forest of Dean, where an estimation of the number has risen in the last few years to over 1,200 animals on the basis of a recent census There is no level of wild boar density below which establishment of disease would be negligible (Bellini et al. 2016). The exposure of contaminated products to this population is dependent on the access to food waste. This is a credible risk pathway and therefore we consider it is likely (moderate uncertainty). Consequence assessment The UK pig population consists of ~4 million animals (10,000 premises) in commercial pig farms, not including non-assured or small holdings or backyard pigs. The feral pig population is several hundreds in isolated populations, the largest of which is the Forest of Dean. In terms of the impact or consequence of ASF infection this is mainly considered for the commercial sector and can be measured in terms of economic impact from high case fatality rates, requirement for culling of affected farms and the significant trade impact, particularly with respect to the valuable third country market (China and Russia) as well as EU trade. There is no public health risk. However, even a case in a feral pig population which leads to a trade ban. Expert elicitation (unpublished) has estimated a reasonable worst case scenario and the likely economic impact based on the value of the sector and the likely number of outbreaks and time that a ban may remain in place. Due to the small discrete populations of feral pigs, we would not expect disease to be maintained in these populations, giving rise to continual reintroductions into the domestic pigs, as seen in Eastern Europe. Nevertheless, the costs of control in a feral boar population would be substantial.