SURVEILLANCE AND RISK
MANAGEMENT DURING THE
LATTER STAGES OF ERADICATION
AUSTRALIA
BRIAN RADUNZ
Darwin
Great
Barrier
Reef
NT
Qld
WA
Ayers Rock
SA
NSW
Perth
Sydney
Vic
Tas
Eastern and Southern Australia
• farming areas
• 150,000 properties
• small herd size (<100 average)
• some herds up to 2000 - 3000 head
• TB free by mid 1980s
TB eradication by standard test and
slaughter techniques
•Europe
•North America
•New Zealand
Central and Northern Australia
Extensive grazing
• < 2000 properties
• large herd size (5000-50,000)
• large property size (3-10 head per
sq km)
• 2000 - 15000 sq kms
TB ERADICATION
•Paddocks
• Bush area
(uncontrolled parts of property)
•
test and slaughter
•
weaner segregation
•
paddock checks
•
destocking (age and bush)
•
completion of destocking
New Steel Yard
AGE DESTOCKING
higher prevalence aged cows and
bulls in controlled areas (early in
campaign)
BUSH DESTOCKING
all cattle from bush areas
(uncontrolled areas)
BREAKDOWN DESTOCKING
exposed cattle (later in campaign)
in response to a breakdown
Bush Destocking
•muster (3-5 years)
•chopper shooting (1-2 years)
•radio tracking (5-7 years)
Radio tracking to
complete destocking
JUDAS ANIMALS
FERAL PIGS
• very common on the flood
plains near Darwin
•
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
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
HERD TB STATUS PROGRESSION
Infected
whole herd negative test (>60 days)
Restricted
whole herd negative test at least 6 months later
Provisionally Clear (QR1)
whole herd negative test at least 6 months later
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
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
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
Primary cases of tuberculosis from 1993 - 2002
1993
8
BTEC
1994 7
1995
8
1996
6
1997
7
1998
4
1999
1
2000
1
2001
0
2002
2
TFAP
Last TB in cattle
Two adjacent water buffalo herds
NT
1999
Qld
2000
WA
1998
SA
1996
NSW
1995
Vic
1991
Last TB Case in Cattle
Tas
1975
Abattoir Surveillance
National Granuloma
Submission Program
(NGSP)
•
To increase the sensitivity of the abattoir
monitoring system
•
Started late 1992
•
ALL granulomas submitted to laboratory
•
8-9 M cattle slaughtered annually
1993 - 97
1998-2002
Kills Ms
36.3
41.1
Granulomas
12992
21148
TB detected
57
10*
* 2 Clusters each with 3 primary cases in each cluster
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
•
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
Origin of granulomas
%
Thorax
23
Head
72
Abdomen
3
Other
2
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
REASONS FOR SUCCESS IN
ERADICATION
•
strong government and industry support
•
joint industry and government funding and
decision making
•
industry funded 50%
• strong technical basis
• no wildlife reservoir hosts
• consistent implementation
• risk manage exposed cattle in latter
stages of the campaign
• granuloma submission program in latter
stages of the program