SURVEILLANCE AND RISK

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SURVEILLANCE AND RISK MANAGEMENT DURING THE
LATTER STAGES OF ERADICATION AUSTRALIA BRIAN
RADUNZ
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Darwin
Great Barrier Reef
Ayers Rock
Perth
Sydney
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• Eastern and Southern Australia
• farming areas
• 150,000 properties
• small herd size (lt100 average)
• some herds up to 2000 - 3000 head
• TB free by mid 1980s

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• TB eradication by standard test and slaughter
  techniques
• Europe
• North America
• New Zealand

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• Central and Northern Australia
• Extensive grazing
• lt 2000 properties
• large herd size (5000-50,000)
• large property size (3-10 head per sq km)
• 2000 - 15000 sq kms

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• TB ERADICATION
• Paddocks
• Bush area
• (uncontrolled parts of property)

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• test and slaughter
• weaner segregation
• paddock checks
• destocking (age and bush)
• completion of destocking

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Test and Slaughter
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Old wooden yard
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New Steel Yard
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Reactor PMS
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AGE DESTOCKING higher prevalence aged cows and
bulls in controlled areas (early in campaign)
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BUSH DESTOCKING all cattle from bush areas
(uncontrolled areas)
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BREAKDOWN DESTOCKING exposed cattle (later in
campaign) in response to a breakdown
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• Bush Destocking
• muster (3-5 years)
• chopper shooting (1-2 years)
• radio tracking (5-7 years)

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Radio tracking to complete destocking JUDAS
ANIMALS
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Radio tracking collar
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Finding the "judas cow"
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Outcome of radio tracking
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Feral water buffalo
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• FERAL PIGS
• very common on the flood plains near Darwin

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• TB (M. bovis) in feral pigs is closely associated
  with TB infected cattle and buffalo
• No TB found in pigs since infected cattle and
  buffalo removed
• Strong evidence that in the Northern Territory
  the feral pig is an end-host
• McInerney et al 1995, Australian Veterinary
  Journal, 72 448-451

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• Risk Management and field surveillance during
  latter stages of the campaign
• Increasing TB testing prior to quarantine release
  
• Additional surveillance testing after quarantine
  release
• Destocking exposed cattle as the primary
  eradication tool
• TB testing used to confirm that low risk cattle
  were not infected

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HERD TB STATUS PROGRESSION Infected whole herd
negative test (gt60 days) Restricted whole herd
negative test at least 6 months
later Provisionally Clear (QR1) whole herd
negative test at least 6 months later
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Confirmed Free 1(QR2) whole herd negative
test at least 12 months later Confirmed Free 2
(QR3) negative test of exposed animals within 8
years Confirmed Free 3
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• In 1999 the Confirmed Free 3 surveillance was
  replaced with additional risk management and
  accelerated commercial slaughter
• incentives and disincentives applied
• financial assistance to accelerate slaughter of
  exposed cows
• reduced financial assistance in the event of a TB
  case if no compliance

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Herds infected with TB from 1 January 1988 to 31
December 1999 and NOT totally destocked
Older than 12 months at exposure
Less than 12 months at exposure
Category A cattle
Category B cattle
Annual TB test of cattle and any in-contact
cattle until slaughter
TB test of cattle and any in-contact cattle every
2 years until slaughter
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Primary cases of tuberculosis from 1993 -
2002 1993 8 1994 7 1995 8 1996 6 1997 7 1998 4 19
99 1 2000 1 Last TB in cattle 2001 0 2002 2 Two
adjacent water buffalo herds
BTEC
TFAP
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NT 1999
Qld 2000
WA 1998
SA 1996
NSW 1995
Vic 1991
Last TB Case in Cattle
Tas 1975
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Abattoir Surveillance National Granuloma Submissio
n Program (NGSP)
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• To increase the sensitivity of the abattoir
  monitoring system
• Started late 1992
• ALL granulomas submitted to laboratory
• 8-9 M cattle slaughtered annually

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1993 - 97 1998-2002
Kills Ms 36.3 41.1 Granulomas 12992 21148 T
B detected 57 10 2 Clusters each with 3
primary cases in each cluster
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• NGSP2
• Targeted NGSP
• Started October 2002
• Phased in introduction - based on date of last TB
  case
• Very low risk States
• meat inspector to submit granuloma only if unsure
  of the cause
• Low risk States
• granulomas from head and thorax only

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• From January 2007 in all States inspectors will
  submit only granulomas if unsure of the cause
• From 2007 TB exclusion will be part of general
  surveillance

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Origin of granulomas Thorax 23 Head 72
Abdomen 3 Other 2
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Diagnosis of granulomas during TFAP (1998 -
2002) Actinobacillosis 49 Rhodococcus 12
Neoplasm 7 Parasitic 4 Fungal
2 Nocardia 1 Other 20 No Diagnosis
5 Tuberculosis 0.04
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• REASONS FOR SUCCESS IN ERADICATION
• strong government and industry support
• joint industry and government funding and
  decision making
• industry funded 50

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• strong technical basis
• no wildlife reservoir hosts
• consistent implementation

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• risk manage exposed cattle in latter stages of
  the campaign
• granuloma submission program in latter stages of
  the program

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