Session 7: Traceability

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Session 7Traceability Follow-up Checks

• John Elphinstone (UK)

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Issues for ring rot/brown rot outbreak

• Immediate actions
• Trace-back activities
• Further investigations of source and possible
  spread
• Cleansing and disinfection
• Disposal measures
• Follow-up activities

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Immediate actions

• Suspicion of infection ( 2 x screening tests
  positive)
• Notice served
• movement of potato on and off farm/unit
  prohibited
• Additional investigations initiated
• Trace-back activities
• Further testing
• Additional measures to prevent spread e.g.
• Restrictions on the use of potentially
  contaminated machinery
• Prohibition of the movement of sister stocks
  suspected of being contaminated.

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Immediate actions

• Confirmation of infection ( pathogen
  identified host test positive)
• Trace-back completed
• Contaminated and probably contaminated potatoes
  and other items identified on premises and
  associated premises
• Official Notice served
• Premises demarcated as a zone contaminated with
  Clavibacter michiganensis ssp. sepedonicus
  (Potato Ring Rot)
• Planting of contaminated and probably
  contaminated potatoes prohibited
• Approved disposal of contaminated and probably
  contaminated potatoes required
• EC notified

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Further testing

• Higher rate to increase likelihood of detecting
  low incidence of infection
• In UK 4000 tubers tested per stock (20 x 200)

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Trace-back activities

• Always trace
• up (seed),
• down (progeny)
• sideways (sister stocks)
• Investigate origin of infected plants and tubers
  to trace the source of infection e.g.
• For certified seed the crop number allows full
  traceability
• Certificate number of seed planted
• Supplier details
• Intermediary wholesalers

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Case study 1 Ring Rot in seed potato, Wales
2003

• The UK's first finding of ring rot confirmed in
  seed potato crop November 2003 in Wales
• Infected tubers found in out-grade material
• One stock of Provento and one stock of a
  Provento/Almera admixture were found to be
  infected
• Source of infection unknown, most data point
  towards infected seed

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The farm

• Seed potato company
• Wales
• 46 ha seed potatoes in 2003
• 22 stocks of seed
• 1 stock of ware

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Pre-outbreak

• Mid-April 2003 8 stocks of NL seed arrived. 17
  tonnes in total.
• All inspected on farm
• 210 tuber sample sent to CSL from each stock
  (latent testing) All negative.

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Pre-outbreak

• All stocks planted by grower on one field on
  rented farm.
• All stocks walked by Inspectors in summer - no
  suspicious symptoms seen.
• Crop harvested at end of September.

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The Outbreak

• October 2003 Ring Rot samples submitted to CSL
  for latent testing. Samples taken whilst doing a
  seed potato export on the farm (8 varieties going
  to the Canary Islands). Provento and Markies.
• 7 November 2003 CSL informed inspectors (PHSI)
  that one variety (Provento) was positive.

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The Outbreak

• Morgrow Seed Potatoes notifed immediately.
• PHSI HQ and NAWAD informed.
• The Commission, Canary Isles Authorities and the
  Merchant notified.

• Grower notified immediately.
• PHSI issued Hold Notice on part of the farm and
  potatoes. Hold notice also issued on all
  recipients of seed potatoes sold off farm during
  autumn.
• PHSI HQ informed.
• The Commission, Canary Isles Authorities and the
  Merchant notified.

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The Outbreak

• 11 November 2003 meeting with grower to gather
  information.
• Ring Rot demonstrated in Provento stock on farm.
• Biosecurity put in place
• Virkon footbaths and Tyvek suits.

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The outbreak

• 13 November 2003 Meeting on farm of growers,
  National Farmers Union, CSL and PHSI
• Dutch Authorities contacted

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The testing

• 7 - 28 November
• All 23 stocks cored (4000 tubers per stock ) by
  PHSI. Overnight delivery to CSL.
• Provento and Almera were positive. (The positives
  in the Almera were found to be Provento
  tubers!!).
• All imported Dutch Almera and Provento stocks
  traced and tested. Dutch tested in Netherlands.
• Associated stocks from 2002 crop and associated
  input stocks for 2003 also cored and tested in UK.

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Verification of potato variety

• Contaminated stock was admixture of two varieties
  
• All contaminated tubers from only one variety
• Trace-back narrowed down to identify source of
  infection

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Disposal of crop

• All contaminated potatoes (Almera and Provento)
  disposed of by deep burial.
• All Probably Contaminated potatoes disposed of
  unwashed in bags marked accordingly, or went for
  processing at a nearby peeler. Very little help
  from PHSI/trade.
• Any remaining Probably Contaminated potatoes
  from farm disposed of by composting.
• Approximately 1800 tonnes of potatoes disposed
  of.
• Estimated loss 400,000 ( 500 000).

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Farm clean-up

• All buildings steam cleaned and sprayed with
  Virkon
• All contaminated boxes burnt. Rest still on farm,
  some sold Autumn 2006.
• Some machinery sold. Remainder still on farm.
• No potato production since 2003.

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Infected field

• Annual survey of infected field that is still
  under notice continues.
• Ground-keepers (volunteers) still present in
  field.
• No potatoes may be grown in field.
• This is the only notice still in force.

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Case study 2 Ring Rot in 2 ware potato crops
England, 2004

• Linked outbreaks in ware potato on farms in
  Lincolnshire Herefordshire
• Both farms supplied with a Dutch stocks of Sante
  in 2003
• The stocks supplied were derived from a Sante
  stock with a clonal link (2000) to a stock also
  implicated in a 2004 ring rot finding in the
  Netherlands.

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Ring rot Trace-back 2004 outbreak
1998
1999
2000
2001
2002
2003
Herefordshire Ware
Herefordshire Ware
2004
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Further investigation of extent and possible
source of outbreak and risk of spread

• Investigations will include
• All potatoes grown at or nearby the contaminated
  premises.
• Premises linked to the outbreak, e.g. by shared
  equipment or contractors.
• Potato from these premises or present at the same
  time as designated potato.
• Central stores handling designated potatoes.
• Machinery, containers, stores, packaging etc.
  linked to the outbreak.
• Potatoes clonally related to known infected
  stocks or stocks grown on contaminated premises.

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Germany - Trace Back 1
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Germany - Trace Back 2
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Germany - Trace Back 3