Proceedings of the 10th International Colloquium on Paratuberculosis

#78
National surveillance for Paratuberculosis in New Zealand Farmed Deer Herds:
Development <strong>of</strong> a Database
Peter Raymond Wilson, Jaimie Hunnam, Cord Heuer, Lesley Stringer, Colin Mackintosh
Massey University, Palmerston North, New Zealand; AgResearch Invermay, Mosgiel, New Zealand
Aim: Develop a national database for paratubercluosis surveillance in New Zealand farmed deer.
Method: Meat inspectors characterise and electronically record lymph nodes (LN) as “normal” or
“enlarged” based on investigation <strong>of</strong> circumference distribution, or resembling tuberculosis (M. bovis) lesions.
During set-up, LN and carcass data from 1,309,566 deer from 3380 farms were recorded from January 2007
– 2009. Data is now recorded from almost every animal slaughtered, expected to be ~0.5 million in 2009, from
every deer slaughterhouse. Data are forwarded regularly to <strong>the</strong> central database for checking and collation.
Validation involved physical and bacteriological investigation.
Results: Evaluation <strong>of</strong> four meat inspectors recording 1287 mesenteric LN (MLN) showed 99% specificity
and 25% sensitivity for categorisation <strong>of</strong> MLN enlargement. Ongoing supervision is improving inspector diagnosis.
Initial screening showed 95% <strong>of</strong>130 “enlarged”, and 69% <strong>of</strong> 154 randomly selected “normal” MLN from 25
farms were Mycobacterium avium subsp. paratuberculosis (MAP) culture and/or histology positive. Data from
subsequent MLN screening <strong>of</strong> four deer per farm from 57 randomly selected farms from four regional slaughterhouses
has been collected for culture and histology for modelling <strong>of</strong> MLN characteristics and frequencies as
a tool for predicting farm infection and possibly clinical disease status. Results will be presented.
Conclusion: The database allows spatial and temporal tracking to quantify and monitor <strong>the</strong> disease and
control measures, reported to industry. Data is being used to heighten awareness <strong>of</strong> paratuberculosis, target
high prevalence herds for intensive control programmes and cost-effectively identify herds <strong>of</strong> various disease
and infection strata for case, case-control, longitudinal and intervention studies to better understand <strong>the</strong> disease.
The database is supported by <strong>the</strong> deer industry and is now owned and managed by an independent
processor-funded agency. Routine analysis and report presentation is by Massey University (see accompanying
abstract), and data is available for approved research purposes.
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