Proceedings of the 10th International Colloquium on Paratuberculosis

#40 Managing Bovine Johnes Disease in South Australia using a Dairy Scoring System
Jeremy Rogers, Peter Nosworthy, Jacobus van Wijk, South Australian Government, Australia
Bovine Johne’s disease (BJD) is endemic in cattle in South Eastern Australia and mainly affects <strong>the</strong> dairy
industry. In Australia dairying is primarily based on irrigated pasture and supplementary feeding <strong>of</strong> cows, ra<strong>the</strong>r
than housed cattle.
Until February 2005, <strong>the</strong> management <strong>of</strong> BJD in <strong>the</strong> South Australian dairy industry involved mandatory
reporting and quarantines to control <strong>the</strong> spread <strong>of</strong> disease from known infected herds plus within herd
measures to control infection; usually a Test and Cull program and improved calf rearing systems. However,
reluctance by producers to report or diagnose BJD in <strong>the</strong>ir herds meant <strong>the</strong> disease continued to spread.
The prevalence <strong>of</strong> BJD in Australian beef herds is very low and beef producers are concerned about <strong>the</strong>
risk from contact with dairy and dairy cross cattle. The financial consequences <strong>of</strong> BJD infection in Australian
pasture based beef herds are large, particularly for seed stock producers. In order to resolve <strong>the</strong> conflicting
interests <strong>of</strong> <strong>the</strong> two cattle sectors, a new strategy was designed using assurance based trading principles to
replace <strong>the</strong> regulatory approach.
By 2009 over 95% <strong>of</strong> SA dairy producers have enrolled in <strong>the</strong> Dairy ManaJD program and test results
confirm <strong>the</strong> low prevalence <strong>of</strong> BJD (17%) in <strong>the</strong> SA dairy sector. Within infected herds <strong>the</strong> prevalence <strong>of</strong> BJD
is typically 1-2% ELISA positives in animals four years and older, and significantly lower in herds undertaking
control measures including Test and Cull programs. The widespread uptake <strong>of</strong> <strong>the</strong> voluntary program has enabled
producers to trade cattle using <strong>the</strong> Dairy Score as a risk assessment tool. Higher scores (tested negative
herds) have attracted higher prices and greater market access both within SA and nationally.
This paper describes <strong>the</strong> methodology and outcomes <strong>of</strong> implementing a voluntary assurance based trading
scheme in <strong>the</strong> SA dairy industry.
#41 Paratuberculosis surveillance in Austria
Eva Geisbauer, Michaela Altmann, Michael Dünser,Institute for Veterinary Disease Control, Linz; Austrian Agency
for Health and Food Safety, Austria; Institute for Veterinary Disease Control, Linz; Austrian Agency for Health and
Food Safety, Australia
Introduction: In April 2006 paratuberculosis in cattle, sheep, goat and farmed deer became a notifiable disease
in Austria. Clinically suspicious animals have to be reported to <strong>the</strong> local authorities.
The aim <strong>of</strong> <strong>the</strong> Austrian paratuberculosis surveillance program is <strong>the</strong> detection and elimination <strong>of</strong> clinical
cases and <strong>the</strong> implementation <strong>of</strong> hygiene and management measures at <strong>the</strong> affected farms.
Material and methods: For laboratory verification <strong>of</strong> clinical infections blood and fecal samples or tissue
samples from <strong>the</strong> intestine, <strong>the</strong> intestinal and hepatic lymph-nodes <strong>of</strong> slaughtered or perished animals, have to
be sent to <strong>the</strong> national reference laboratory for paratuberculosis. Blood samples are tested by ELISA (Pourquier,
Montpellier, France) for Mycobacterium avium subspecies paratuberculosis (MAP) specific antibodies. For
<strong>the</strong> detection <strong>of</strong> MAP in feces a commercially available real-time PCR kit (Adiagene, France) is used.
Results: Between <strong>the</strong> years 2006 and 2008 samples from 459 clinically suspicious cattle from 185 farms,
from 26 sheep (4 farms), from 2 goats (2 farms) and from 4 farmed deer (2 farms) were examined according to
<strong>the</strong> regulations. 120 cattle and one sheep were tested positive. Table 1 lists <strong>the</strong> positive results by laboratory
method.
Table 1: Positive results in cattle by laboratory method. Number <strong>of</strong> positive samples: ELISA pos/ PCR (feces)
pos: 81; ELISA pos/ PCR (feces) neg: 5; ELISA neg/ PCR (feces) pos: 11; ELISA pos: 7; PCR (feces) pos:
7; PCR (tissue) pos: 9
Discussion: Because <strong>of</strong> <strong>the</strong> difficulties in detecting <strong>the</strong> subclinically infected animals, it is unlikely to obtain
paratuberculosis-free herds. This surveillance program is aiming at <strong>the</strong> detection and elimination <strong>of</strong> clinical
cases in order to reduce <strong>the</strong> infection pressure in <strong>the</strong> affected farms. Due to intermittent shedding and pre-mortal
antibody-decrease a combination <strong>of</strong> ELISA and real-time PCR is applied.
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