While African Swine Fever has made remarkable inroads into China - causing at least 8 outbreaks across 5 provinces since August 1st - the virus is also burning its way through swine farms across a wide swath of Eastern Europe and parts of Russia.
Although not a threat to human health, ASF is highly contagious and often fatal in swine - and with no vaccine available - the only recourse is to cull all sick or potentially exposed swine.Over the past couple of years we've seen a marked increase in ASF reports from Eastern Europe, and in August of 2017 DEFRA raised the risk of seeing the virus imported into the UK to `Low'.
As recently as 5 days ago (see Aug 28th's DEFRA: Update On African Swine Fever (ASF) In Eastern EU), this risk assessment has remained unchanged, but after reviewing the recent surge in ASF outbreaks in Eastern Europe, today DEFRA is announcing that risk has been raised to `Medium'.
During that last update, I mentioned:
While the OIE lists the source of this outbreak as `unknown or inconclusive', a report appearing two days ago in Pig's Progress (ASF on Romania’s largest pig farm: 140,000 pigs culled) suggests some smallholders in the region may have been dumping dead pigs into the river, and the virus has infected downstream farms drawing water from the Danube.Today's update spends considerable time discussing these concerns, and finds this scenario at least plausible. First, some excerpts from the latest DEFRA Risk Assessment (Dated Aug 31st, but just released), then I'll return with more.
Updated Outbreak Assessment #17
African Swine fever in Eastern Europe
31 August 2018
Ref: VITT/1200 ASF in Eastern Europe
Since our last report on the 23 rd August, there have been several outbreaks in large commercial pig farms in Romania and Poland. In addition, Bulgaria has reported the first outbreak in backyard pigs in Varna region.
Romanian origin meat represents less than 0.5% of the total pig meat consigned to the UK from EU MSs, but nevertheless that still represents several thousand tonnes per annum. Fresh or frozen pig meat from any ASF-restricted zone cannot be consigned to other EU member states, but commercially produced fresh or frozen pig meat derived from pigs raised outside the restriction zones can continue to be traded.
Live pigs originating in Part III areas (Decision 2014/709/EC) can be slaughtered for fresh or frozen meat for the internal market only, but a derogation in the decision allows pigs from Part III areas and the free area to be slaughtered in the same establishment, provided there is complete separation of the two groups of pigs within the slaughter house throughout the process.
There is a valid concern amongst some pig farmers in Romania that ASF virus-contaminated water may be a route of entry of infection into farms; for example if an infected carcase or infected blood, tissues, urine or faeces contaminate the source of drinking water.
Experimental data suggest an infectious dose via the oral or nasal route of 1x10 2 -10 3 50% haemadsorbing doses (HAD 50 ) and blood from an infected pig can contain between 10 6 and 10 8 HAD 50 /ml (Pietschmann et al. 2015).
The survival of ASF virus in skin, fat or putrefied blood is many weeks (Davies et al., 2015; EFSA, 2010). The rate of decay or release of virus with time from a carcase in water is not known, but the dilution factor could be 10 3 to 10 5 fold and if the minimum infectious dose for ASF virus was assumed to be a single infectious particle, there would still be a large dilution effect in water.
Nevertheless the daily water intake of a 20-40 kg pig is estimated at 5 to 6 litres of water a day (https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_ data/file/69369/pb7950-pig-code-030228.pdf) therefore this is a credible risk route for pigs for which the drinking water vulnerable to contamination by infected pigs or wild boar.
According to the EU Trade Notification System, TRACES, there have been six consignments of frozen pig meat from Romania consigned to the UK in the last month and we are following up on the origin of the animals, vis à vis the restriction zones.
The risk of ASF introduction to the UK was previously raised to “low” in August 2017. This was because, despite the relatively low level of legal trade in live pigs or commercially produced pig products, there could be a risk from the fomite pathway involving movement of people and vehicles from affected Eastern EU countries and the evidence around the findings of contaminated / infected non-EU origin pig products detected in the EU.
We have reassessed the risk and consider that, on a temporary basis, given the increase in ASF outbreaks in commercial pigs in the last two weeks and the continued import of frozen pork meat from affected countries, the risk is increased to MEDIUM for the entry of contaminated or infected products into UK both over the last month and looking forward.
This risk level will be reassessed every two weeks.
The risk of exposure to the pig population in the UK is still dependent on the level of biosecurity on pig premises and is still considered to be “LOW”, although the situation is being kept under review.
We would like to highlight to all pig keepers and the public to ensure pigs are not fed catering waste, kitchen scraps or pork products, thereby observing the swill feeding ban. All pig keepers should be aware that visitors to their premises should not have had recent contact with affected regions. Anybody returning from the affected EU MSs should avoid contact with domestic pigs, whether commercial holdings or smallholdings, areas with feral pigs or wild boar, until they are confident they have no contaminated clothing, footwear or equipment.
Although mortality in infected animals is almost 100%, the initial rate of ASF spread in a pig farm can be slow, therefore the possibility of ASF should be considered even for single pigs with haemorrhagic lesions, lethargy, skin discolouration or petechiation and high fever. Pigs suspected to be affected with African or classical swine fever must be reported immediately to APHA - please see https://www.gov.uk/guidance/african-swine-fever for more information. Pig keepers and veterinarians should remind themselves of the clinical signs for ASF and images and descriptions of clinical signs and pathology of ASF are provided on this link: https://www.flickr.com/photos/defragovuk/sets/72157694954571532/(Continue . . . . )
Recent events have forced other countries in Western Europe, across Asia (see South Korea Detects ASF Gene In Chinese Food Products), and even here in North America (see Swineweb's African Swine Fever in China Prompts Call for Review of Biosecurity on Canadian Farms) to reevaluate the risks, and take steps to try to prevent entry of ASF.
A week ago, in African swine fever (ASF) threatens to spread from China to other Asian countries, the FAO described how easily ASF can cross borders, and even oceans.
A robust virus with a long lifeWhile the immediate impact of ASF is economic, for countries with high food insecurity, the loss of massive amounts of pork products due to African Swine Fever (or the culling to prevent its spread) could have destabilizing effects as well.
The ASF virus is very hardy and can survive long periods in very cold and very hot weather, and even in dried or cured pork products. The strain detected in China is similar to one that infected pigs in eastern Russia in 2017 but, so far, and while the investigations continue, the China Animal Health and Epidemiology Center has found no conclusive evidence of this latest outbreak's source or linkages.
"The movement of pig products can spread diseases quickly and, as in this case of African Swine Fever, it's likely that the movement of such products, rather than live pigs, has caused the spread of the virus to other parts of China," explained Juan Lubroth, FAO's Chief Veterinarian.
As we've discussed previously in this blog, food insecurity - whether due to disease, floods, droughts, or other causes - can pose both severe economic and societal challenges (see Iran: Bird Flu, Food Insecurity & Civil Unrest).All of which could make the spread of ASF (along with other livestock diseases like FMD, PED, PRRS, and avian flu) significant geo-political factors going forward in this already challenging 21st century.