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Waterborne pathogens: evolution of prevalence and current challenges Henry-Michel CAUCHIE

This article discusses the evolution of waterborne pathogens and the challenges faced in ensuring water safety. It covers the prevalence and impact of various waterborne pathogens, implementation of water safety plans, dynamics of outbreaks, and the use of molecular biology tools in monitoring labs. It also explores the emerging health problem of Legionella and the interplay between foodborne and waterborne diseases. The article concludes by examining the evolution of water reuse and the need for risk-based analysis in water management.

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Waterborne pathogens: evolution of prevalence and current challenges Henry-Michel CAUCHIE

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  1. Waterborne pathogens: evolution of prevalence and current challengesHenry-Michel CAUCHIE 2. Fachsymposium "Spurenstoffe und Krankheitserreger im Wasserkreislauf„ Belval Luxembourg October 2nd, 2019

  2. Water-relatedpathogens Parasites 5 - 15 µm Bacteria 500 nm - 3 µm Viruses 20-100 nm

  3. Water-relatedpathogens ORAL Vibriocholerae PathogenicE.coli Norovirus Enterovirus Campylobacterspp Cryptosporidiumparvum Giardia lamblia FECAL

  4. Legionellapneumophila Optimal developmenttemperaturearound 42C (association with biofilm)

  5. Cyanobacteria Hepatotoxins (microcystins) Neurototoxins (Saxitoxin Anatoxin-a) Cytotoxins (cylindrospermopsin) Dermatotoxins (lungbyatoxin)

  6. Pakistan ~ 37,000 deaths per year India ~ 250,000 deaths per year Nigeria ~ 120,000 deaths per year Vibriocholerae Ethiopia ~ 42,000 deaths per year DRC ~ 42,000 deaths per year

  7. Salmonella typhi

  8. Drinking water treatment

  9. Water Safety Plan Water Sanitation Plan

  10. Dynamics of outbreaks in the US (1971 – 2014) Milwaukee outbreak 400,000 people infected Deaths of eldery and immunocompromised people Walkertonoutbreak E coli O157; Campylobacterjejuni 2,300 infected/5,000 7 deaths 1971 – 2014 n = 968

  11. Dynamics of outbreaks in the US (1971 – 2014)

  12. Dynamics of outbreaks in the US (1971 – 2014)

  13. Challenges in drinking water safety • Global implementation of the Water safety plan • Techniques available • Improvement on governance • Implementationof the multiple barrierapproach • Adapted to the actualmicrobialhazard •  implementation of molecularbiologytools in the monitoring labs •  Adoption of the Quantitative MicrobialRiskAssessment • Emergence of Legionellaas a major healthproblem but linked to specific water infrastructure

  14. Major ethiologic agents today Campylobacter Norovirus Cryptosporidium/Giardia

  15. Campylobacter: linkinkfoodborne and waterbornediseases • Interplaybetweenfoodborne and waterborne • Concept of One-Health!

  16. New conceptualframeworkof water management +

  17. And in Recreational waters? Campylobacter?

  18. Next challenges: the evolution of water reuse

  19. Quantitative microbial risk assessment Hazard identification : Salmonella enterica Exposure assessment Amha et al., 2015. A probabilistic QMRA of Salmonella in direct agricultural reuse of treatedwastewater. Wat SciTechnol 71.8: 1203-1211.

  20. How works QMRA ? Exposure assessment • Determination of the ingested dose (λ): probabilistic approach Cpath .e-kt.Vprod.10-w.Ming.Mcorp= λ Cpath t

  21. Comment estconstruit un QMRA? Exposure assessment For one isolated ingestion When exposure is repeated n times Pannual = 1 – [1- P(response)]n DALYs = Pannual . DALYper case . Sfraction

  22. Results Acceptable annual risk USEPA Acceptable annual risk USEPA Acceptable annual risk USEPA

  23. Cultural barriers

  24. Evolution of the europeanlegislation Water reuserisk management plan

  25. Cyanobacteria Hepatotoxins (microcystins) Neurototoxins (Saxitoxin Anatoxin-a) Cytotoxins (cylindrospermopsin) Dermatotoxins (lungbyatoxin)

  26. Development in Europe

  27. Evolution of legislation

  28. chalLengesrelated to the cyanobacteria • No in situ treatmentexcept the management of eutrophication on the long term and large scales. • Oxydation treatments are howeverefficient (pay attention to the governance) • How to integrate the high spatial and temporal variability in the monitoring schemes

  29. Real-time monitoring and spatialisation of cyanobacteriaoccurence

  30. A global healthsafety plan Water reuse • Lessautomatic application of legislation • More locallyadaptedriskbasedanalysis

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