1. No category

Water slide:
Vesivälitteiset kampylobakteeriepidemiat Suomessa
Waterborne Campylobacter outbreaks in Finland
22nd May 2015
Evira, Helsinki, Finland
25.5.2015
Tarja Pitkänen, Ph. D, Senior Researcher
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Drinking water in Finland
• Raw water sources
– Surface water 35 %
– Ground water 46 %
– Artificial ground water 19 %
• Around 1 400 water works
– A definition of water works = more than 50 consumers
– Distribute drinking water for ca. 4.8 million people
• 500,000 inhabitants in rural area use private wells as drinking
water source
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Drinking water quality in Finland
• Strenghts
– Abundance of water
– Scarcity of contaminating activities
– Low water temperature
• Challenges
– Small waterworks
– Shallow groundwater
– Long distances between the
consumers
– No disinfection in most drinking water
distribution systems
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Tarja Pitkänen
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Microbial compliance of tap water samples in
Finland
100%
99%
98%
97%
10 - 100 m3/d
100 - 400 m3/d
400 - 1 000 m3/d
> 1000 m3/d
96%
95%
94%
93%
92%
91%
E. coli
Enterococci
Coliforms
Total count
Zacheus, O. (2010) Talousveden valvonta ja laatu vuonna 2008, National Institute for Health and
Welfare, Avauksia 18 / 2010. Available on Internet: http://www.thl.fi/thl-client/pdfs/36e9255a-2e2c409a-ac0f-d2239eccc439 [In Finnish].
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Number of waterborne outbreaks
12
10
Compulsory notification
system for waterborne
outbreaks
8
6
4
2
0
80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 07 08 09
Year
Tarja Pitkänen
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Groundwater contamination as a cause of
waterborne outbreaks
Abstraction wells in sand/gravel
mining sites
Kuvat: Ilkka Miettinen, THL
Lake/river bank filtration
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Contaminant intrusion into DWDS as a cause
of waterborne outbreaks
Nokia 2007
Vuorela 2012
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MIWSA / Tarja Pitkänen
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Number of illness cases per causative agent
Giardia; 400
Chemicals;
27
Unknown; 2629
Rotaviruses;
1140
Campylobact.;
6413
Noroviruses;
16772
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Waterborne infection risk management
• Priorities in health policy
– Quantitative Microbial Risk
Assessment (QMRA): is the risk
estimate acceptable?
– Multi-barrier approach and water
safety planning (WSP) may give
tools how
• to improve water safety
• to reach the water quality targets
• Balancing between consumer
safety and (consumer) costs
– Cost-benefit assessment
• illness vs. investments
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Tarja Pitkänen, Ph.D
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Contaminants in water storage towers as a
cause of waterborne illnesses (1/4)
Ristiina 2004
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Tarja Pitkänen
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Pitkänen, T., Miettinen, I. T., Nakari, U.-M., Takkinen, J., Nieminen, K., Siitonen, A., Kuusi, M., Holopainen, A. and Hänninen
M.-L. (2008) Faecal contamination of a municipal drinking water distribution system in association with Campylobacter jejuni
infections. Journal of Water and Health 6(3): 365-376.
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Contaminants in water storage towers as a
cause of waterborne illnesses (2/4)
Vihti 2005
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Figure. The number of illness cases during the
outbreak Autumn 2005.
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Contaminants in water storage towers as a
cause of waterborne illnesses (3/4)
Vuorela 2012
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Tarja Pitkänen
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Figure 2. Epidemic curve of a waterborne outbreak in Vuorela, July 2012 based on the reported
onset date of illness of the cases, and E. coli bacteria counts and chlorine levels in the point 7 (See
Fig. 1) of the water distribution network.
Jalava K, Rintala H, Ollgren J, Maunula L, et al. (2014) Novel Microbiological and Spatial Statistical Methods to Improve Strength of
Epidemiological Evidence in a Community-Wide Waterborne Outbreak. PLoS ONE 9(8): e104713.
doi:10.1371/journal.pone.0104713
http://www.plosone.org/article/info:doi/10.1371/journal.pone.0104713
Contaminants in water storage towers as a
cause of waterborne illnesses (4/4)
Outbreak in October 2014
– Contamination (E. coli) detected already in July 2014
à Cleaning of the storage tower
– Leaking roof was not repaired
à Almost 100 persons got illness
Söderkulla 2014
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A list of published reports on waterborne
Campylobacter outbreaks (1978-2010)
Reference: Pitkänen, T. (2013) Review of Campylobacter spp. in drinking and environmental waters. J Microbiol Meth. 95(1): 39-47.
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Freshwater resources
• Drinking water production, food production, recreation
• Recipients of wastewater effluents and diffuse loading
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Phases and options of Campylobacter
detection in aquatic environments
Collection of a water sample
Sample processing
E.g. membrane filtration
Culture-based
methods
Selective enrichment in broth(s)
The number of tubes defines if results are
qualitative or quantitative
Plating out on selective solid
medium
Preliminary steps
Molecular methods
Extraction of nucleic acids
In situ hybridization
E.g. DNA extraction kits
E.g. FISH
Detection (and
quantification) of the target
Microscopy
E.g. PCR and qPCR
Confirmation tests
Tests for motility, oxidase and catalase
activities, absense of aerobic growth
Analytical steps
Species identification
Confirmatory steps
Typing between the strains
Reference: Pitkänen, T. (2013) Review of Campylobacter spp. in drinking and environmental waters. J Microbiol Meth. 95(1): 39-47.
Challenges in
water
microbiology
• Need for direct molecular methods
– Culture methods are time-consuming
• Need for increased sensitivity
– Target microbes are diluted in large water volumes
• Need for source tracking
– Unsolved water contamination episodes
– Proactive prevention instead of reactive response to contaminations
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Thank you for your attention!
www.thl.fi/vesi
[email protected]
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