surveillance and risk management during the latter stages of eradication australia brian radunz

SURVEILLANCE AND RISK

MANAGEMENT DURING THE

LATTER STAGES OF ERADICATION

AUSTRALIA

BRIAN RADUNZ

Qld

NSW

SA

WA

Vic

Tas

NT

Darwin

Ayers Rock

Great Barrier

Reef

Sydney

Perth

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

• TB testing used to confirm that low risk cattle were not infected

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

1994 7

1995 8

1996 6

1997 7

1998 4

1999 1

2000 1 Last TB in cattle

2001 0

2002 2 Two adjacent water buffalo herds

BTEC

TFAP

Qld2000

NSW1995

SA1996

WA1998

Vic1991

Tas1975

NT1999

Last TB Case in Cattle

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