Prof Trevor W Drew OBE Director, Australian Animal Health Laboratory Geelong, Australia Visiting Professor, Jilin University, PR China Guest Professor, University of Nottingham, UK GF-TADS SGE-ASF-ASIA, JULY-AUG 2019 Biosecurity & Border control: Where the virus can be found - What to look for - What to test
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Biosecurity & Border control - Regional Representation OIE ... · 1.12.2019 · • Follow OIE Code for legal imports ... can help to inform assessment of risk • Useful for persuading
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Prof Trevor W Drew OBE Director, Australian Animal Health Laboratory Geelong, AustraliaVisiting Professor, Jilin University, PR ChinaGuest Professor, University of Nottingham, UKGF-TADS SGE-ASF-ASIA, JULY-AUG 2019
Biosecurity & Border control: Where the virus can be found - What to look for - What to test
“there is little doubt ASF will continue its geographic expansion…” (FAO EMPRES, 2012)
• Potential for serious impact on global trade and food security
• Pork considered a priority protein source for meeting future global dietary needs
• Significant investment area for small holder subsistence farmers (‘backyard sector’) in the developing world
• Food security = regional stability
• Major world players are committed to ongoing research to solve the problem
ASF: a global threat
African swine fever | Trevor Drew | Page 2
Implications for the region are significant
Robinson (2014)
African swine fever | Trevor Drew | Page 3
Definition of contagiousness
percentage of animals which get infected after contact with an infectious agent.
i.e. the probability that an animal picks up an infection after contact with a pathogen
Dependent on whether transmission is directly via an infected animal by the parenteral route, or via ingesting infected meat
How contagious is ASF?
African swine fever | Trevor Drew | Page 4
(30%)
Thanks to Klaus Depner, FLI, Germany
ASF Contagiousness
Within a group (within a pig barn)
Requires high virus dose (>1000
HAU) for parenteral transmission
between groups (open system…e.g. forest)
Requires low virus dose (<100 HAU) for oral transmission
HIGH
LOW
How contagious is ASF?
African swine fever | Trevor Drew | Page 7
Thanks to Klaus Depner, FLI, Germany
ASF virus is a relatively stable virus
ASFV survives the process of
putrefaction and carcasses
may remain infectious for weeks –
longer in cold climates
ASFV therefore presents a high
risk to free countries
• frozen meat: indefinitely
• dry meat and fat: almost one year
• blood, salted meat and offal: more than 3 months
• faeces: over one week
Temperature plays an important role in decreasing the survival
duration of ASF virus in any matrix.
African swine fever | Trevor Drew | Page 8
Thanks to Klaus Depner, FLI, Germany
Two main elements:
a) Preventing the virus from entering the country
• Pre-border activities
• Activities at the border
• Illegal/incidental breaches
b) Preventing the virus from infecting a pig• Farm biosecurity
• Including activities of the veterinary authority
• Wild & feral pigs
• Behaviours – all sectors
In BOTH cases, identifying risk pathways and employing robust mitigation steps are key
Keeping your country free
African swine fever | Trevor Drew | Page 7
Risk factors for spread of ASFDirect
• Infected domestic pigs
– Live cover
• Wild boar, carcases, abortions
• Pig products (swill feeding, spray-dried blood)
• Shared needles for vaccination, non-licensed preparations (eg autogenous vaccines)
• Germplasm, semen(?)
Indirect• Infected pens
• Contaminated feed, water
• Transport - lorries
• Personnel, veterinary visits
– Clothing, boots, instruments
– Part-used vaccines
African swine fever | Trevor Drew | Page 8
Ticks ???
Unlikely
Greatest risk
Illegal movement of pigs => legal movement of pigs
Illegal import of pig products => legal imports
Accidental introduction <=> accidental release
• Carcases in rivers, wild boar migration, release from laboratories
Solution:
• Follow OIE Code for legal imports
• Prevent illegal introduction of animals and products
• Identify and mitigate risks of accidental introduction or release
Preventing the virus from entering the country
African swine fever | Trevor Drew | Page 9
ASF is mainly introduced by HUMANS!
Pigs and products - OIE Code Chapter 15.1
• ONLY canned meat and gelatine are considered “safe” commodities• Specified conditions for heat inactivation – F0 of =>3 (3’ @ 121°C equivalent)
• ALL other commodities should follow the guidelines for import • 25 Clauses provide details
• Dependent on commodity
• Consider source country status
• Whether from domestic, or wild & feral pigs
• Involve quarantine and testing
Key issues in preventing introduction (1)
African swine fever | Trevor Drew | Page 10
• Movement of wild and feral pigs from infected countries• Metapopulations – move around
• Natural barriers may prevent movement
• Hunting with dogs can drive wild & feral pigs to new areas
• Good communication with neighbouring countries is key
• “Amber” response when risk is considered greater?
• Increased passive surveillance
• Testing for exclusion
• Establishment of a Protection Zone
• High risk area – eg adjacent to an infected country
• Different rules – eg no pigs allowed to be kept, or no commercial piggeries
• Increased clinical surveillance
• Removal of wild boar from the area?
African swine fever | Trevor Drew | Page 11
Key issues in preventing introduction (2)
African swine fever | Trevor Drew | Page 12
Key issues in preventing introduction (3)
• Prevent passengers from bringing meat products into your country
• Also for other diseases
• Clear messaging
• Random/targeted inspections
• Fines/other punishment – more messaging
• Random testing of seized products can help to inform assessment of risk
• Useful for persuading government of the need for change in protocols
• Can generate additional publicity
Preventing infection of your wild & feral pigs:
• Access to infected waste food
• Travel across borders to an infected country
• Contact with wild boar from an infected country
• Hunters sometimes like to “supplement” local populations• Illegally bringing in wild boar
• Supplementary feeding during winter months
Encourage reporting of “found dead” wild & feral pigs• Engage with hunters
• They can play an important role in surveillance
• Inform them of the risks
• Test dead animals and remove the carcases
Key issues in preventing infection (1)
African swine fever | Trevor Drew | Page 13
Preventing infection of domestic pigs:
• Swill feeding
• Difficult to prevent in backyard systems
• MUST be boiled – 30 min minimum
• Scavenging - discourage
• Food dumps
• Roadside/village scavenging
• Disposal of airline waste & seized products
• Germplasm from overseas (unless it follows OIE Code)
• Semen should be regarded as a source of infection, though evidence is scant
• Imported feed – especially those containing “growth additives”
• Unlicensed vaccines/autogenous vaccines
Good husbandry – quarantine/all-in:all-out, disinfection; restricted access
THESE MEASURES ARE UNLIKELY TO BE ACHIEVEABLE IN VILLAGE SYSTEMS
Key issues in preventing infection (2)
African swine fever | Trevor Drew | Page 14
• Pigs in pens• Not allowed to roam/scavenge/mingle with pigs from other premises
• Pens with solid walls are best
• Replacement stock – trusted sources, healthy. AVOID live cover!
• Fencing• Pig-proof outer boundary – some distance from pens