1. Spatial Clustering and Multivariate Statistics in
Analysis of Infectious Diseases
Lukáš MAREK
This presentation is co-financed by the
European Social Fund and the state
budget of the Czech Republic

2. Why Geographical Information Systems?
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Advanced methods for spatial analyses
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Spatial statistics
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Exploration of spatial pattern
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Visualization and presentation for non-geographers
(doctors, specialist)
2nd InDOG Doctoral Conference, 14th October - 15th October 2013, Olomouc

3. Spatial Analyses of Health Data - AOI
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Disease mapping
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Visual description of spatial variability of the disease incidence
Maps of incidence risk, identification of areas with high risk
Geographic correlation studies
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Analysis of associations among the incidence and
environmental factors
Analyses of spatial pattern
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Exploration of spatial and spatio-temporal patterns in data
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Disease clusters, randomness, …
2nd InDOG Doctoral Conference, 14th October - 15th October 2013, Olomouc

4. Health and Medical Data
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require specific procedures because of their
confidentiality
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management, presentation and operations
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aggregated, anonymized or incomplete data sets
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usage of suitable analytical procedures, while the
uncertainty and the inaccuracy of data characteristics
need to be taken into account during the analysis and
interpretation of results
2nd InDOG Doctoral Conference, 14th October - 15th October 2013, Olomouc

5. Data Privacy
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Health and medical data = private, confidential and
sensitive data
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Keeping all available records but prevent their reidentification
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Usefulness of the local scale analysis X privacy protection
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Unlikely to explore the relations on the individual level
(and not necessary)
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Availability, accessibility and restrictions
2nd InDOG Doctoral Conference, 14th October - 15th October 2013, Olomouc

6. Software
2nd InDOG Doctoral Conference, 14th October - 15th October 2013, Olomouc

7. Objectives
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Disease occurence as the event
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Spatial evaluation of infectious diseases in Olomouc
Region, Czech Republic
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Space, time, attributes
Spatial (point) pattern
Parotitis, Salmonella, Viral intestinal infections
Spatial evaluation of Campylobacter infection in the
Czech Republic
2nd InDOG Doctoral Conference, 14th October - 15th October 2013, Olomouc

8. Campylobacteriosis
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Campylobacter bacterium (C. jejuni)
Frequent
Often foodborne
Symptom are similar to salmonella
Poultry or fresh milk products
2nd InDOG Doctoral Conference, 14th October - 15th October 2013, Olomouc

9. Data
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Collaboration with Regional Public Health Service in Olomouc
and the National Institute of Public Health
EPIDAT database
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Mandatory records about infectious diseases and patients,
manually fulfilled
Age, Sex, Date, Profession, Place of residence, infection, isolation,
…
2008 - 2012
≈ 100 000 records
(weakly) Anonymized
Aggregation

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Hexagons with the size of average cadastral unit, administrative
units
EUROSTAT population grid
2nd InDOG Doctoral Conference, 14th October - 15th October 2013, Olomouc

10. 2nd InDOG Doctoral Conference, 14th October - 15th October 2013, Olomouc

11. Time
2nd InDOG Doctoral Conference, 14th October - 15th October 2013, Olomouc

12. Disease mapping
2nd InDOG Doctoral Conference, 14th October - 15th October 2013, Olomouc

13. 2nd InDOG Doctoral Conference, 14th October - 15th October 2013, Olomouc

14. 2nd InDOG Doctoral Conference, 14th October - 15th October 2013, Olomouc

15. Identification of Spatial Processes
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Estimation of the nature of phenomenon
Plenty of methods
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Testing of Complete Spatial Randomness
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Global vs. Local
Graphical vs. Numerical
Or other spatial processes
Scale dependency
Bayesian modelling
2nd InDOG Doctoral Conference, 14th October - 15th October 2013, Olomouc

16. Spatial Pattern
2nd InDOG Doctoral Conference, 14th October - 15th October 2013, Olomouc

17. 2nd InDOG Doctoral Conference, 14th October - 15th October 2013, Olomouc

18. Local Moran‘s I with EB Rate
2nd InDOG Doctoral Conference, 14th October - 15th October 2013, Olomouc

19. Multivariate Clustering
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Similarity searching in
attribute space
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Classification of areas with
related properties of
occuring diseases and their
parameters
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Classification of similar
cases
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Without spatial relations
2nd InDOG Doctoral Conference, 14th October - 15th October 2013, Olomouc

20. 2nd InDOG Doctoral Conference, 14th October - 15th October 2013, Olomouc

21. 2nd InDOG Doctoral Conference, 14th October - 15th October 2013, Olomouc

22. Problems / Challenges
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Geocoding
Aggregation
Age / Population standardization
Neighbourhood estimation
Modifiable areal unit problem
Probability distribution of the disease occurrence
Underlying processes
Under / Overestimation of results leading to
misinterpretation
2nd InDOG Doctoral Conference, 14th October - 15th October 2013, Olomouc

23. Future work
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Spatio-temporal analysis
(More of) Bayesian modelling and smoothing
Multivariate statistics with spatial relations
2nd InDOG Doctoral Conference, 14th October - 15th October 2013, Olomouc

24. Thank you for your attention
2nd InDOG Doctoral Conference, 14th October - 15th October 2013, Olomouc