TECHNICAL GUIDANCE on WATER-RELATED DISEASE SURVEILLANCE Office for Europe
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The WHO Regional TECHNICAL GUIDANCE ON WATER-RELATED DISEASE SURVEILLANCE Office for Europe The World Health Organization (WHO) is a specialized agency of the United Nations created in 1948 with the primary responsibility for international health matters and public health. The WHO Regional Office for Europe is one of six regional offices throughout the world, each with its own programme geared to the particular health conditions of the countries it serves. Member States Albania Andorra Armenia Austria Azerbaijan Belarus Belgium Bosnia and Herzegovina Bulgaria Croatia Cyprus Czech Republic Denmark Estonia Finland France Georgia Germany Greece Hungary Iceland Ireland Israel Italy Kazakhstan Kyrgyzstan Technical guidance Latvia Lithuania Luxembourg Malta on water-related Monaco Montenegro Netherlands Norway disease surveillance Poland Portugal Republic of Moldova Romania Russian Federation San Marino Serbia Slovakia Slovenia Spain Sweden Switzerland Tajikistan The former Yugoslav Republic of Macedonia Turkey Turkmenistan Ukraine United Kingdom Uzbekistan ISBN 9789289002417 World Health Organization Regional Office for Europe Scherfigsvej 8, DK-2100 Copenhagen Ø, Denmark Tel.: +45 39 17 17 17. Fax: +45 39 17 18 18. E-mail: [email protected] Web site: www.euro.who.int Cover photo: © iStockphoto Technical guidance on water- related disease surveillance Edited by: E. Funari, T. Kistemann, S. Herbst and A. Rechenburg ABSTRACT This technical guidance is intended to assist the Parties to the Protocol on Water and Health to the 1992 Convention on the Protection and Use of Transboundary Watercourses and International Lakes in establishing and/or strengthening outbreak detection and early warning systems, contingency plans and capacity response in accordance with article 8 of the Protocol. The draft guidance reviews the main threats to health related to water services, recalls basic concepts of epidemiology and disease surveillance and provides guidance on data management and analysis. It will therefore also support national efforts towards national and international health security in line with the International Health Regulations (2005). The guidance was approved by the Parties at the second session of the Meeting of the Parties (Bucharest, Romania, 23–25 November 2010) KEYWORDS ENVIRONMENTAL MONITORING – methods EPIDEMIOLOGICAL SURVEILLANCE – methods WATER POLLUTION – prevention and control WATER POLLUTION, CHEMICAL WATER MICROBIOLOGY DISEASE TRANSMISSION GEOGRAPHIC INFORMATION SYSTEMS TECHNICAL COOPERATION GUIDELINES Address requests about publications of the WHO Regional Office for Europe to: Publications WHO Regional Office for Europe Scherfigsvej 8 DK-2100 Copenhagen Ø, Denmark Alternatively, complete an online request form for documentation, health information, or for permission to quote or translate, on the Regional Office web site (http://www.euro.who.int/pubrequest). ISBN 978 92 890 0241 7 Cover photo: © iStockphoto © World Health Organization 2011 All rights reserved. The Regional Office for Europe of the World Health Organization welcomes requests for permission to reproduce or translate its publications, in part or in full. The designations employed and the presentation of the material in this publication do not imply the expression of any opinion whatsoever on the part of the World Health Organization concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. Dotted lines on maps represent approximate border lines for which there may not yet be full agreement. The mention of specific companies or of certain manufacturers’ products does not imply that they are endorsed or recommended by the World Health Organization in preference to others of a similar nature that are not mentioned. Errors and omissions excepted, the names of proprietary products are distinguished by initial capital letters. All reasonable precautions have been taken by the World Health Organization to verify the information contained in this publication. However, the published material is being distributed without warranty of any kind, either express or implied. The responsibility for the interpretation and use of the material lies with the reader. In no event shall the World Health Organization be liable for damages arising from its use. The views expressed by authors, editors, or expert groups do not necessarily represent the decisions or the stated policy of the World Health Organization. CONTENTS Preface .............................................................................................................................i Acknowledgements...........................................................................................................ii Abbreviations .................................................................................................................. iv 1. Introduction .................................................................................................................1 2. Health risks from microbial pathogens ...........................................................................6 2.1. Definitions ..........................................................................................................6 2.1.1. Legal definitions 6 2.1.2. Epidemiological definitions 6 2.2. Diarrhoeal diseases .............................................................................................7 2.3. Bacteriological pathogens ....................................................................................8 2.3.1. A brief historical note 8 2.3.2. Cholera 9 2.3.3. Typhoid fever 10 2.3.4. Shigella 10 2.3.5. Campylobacter 11 2.3.6. Pathogenic E. coli strains 12 2.3.7. Legionellosis 13 2.4. Viral diseases – viral hepatitis A .........................................................................13 2.5. Protozoan diseases............................................................................................15 2.5.1. Cryptosporidiosis 15 2.5.2. Giardiasis 16 2.6. Diseases of high local importance.......................................................................16 2.6.1. Helminthic diseases 16 2.6.2. Cyanobacteria in drinking-water 17 2.7. Monitoring ........................................................................................................21 3. Health risks from chemicals.........................................................................................23 3.1. Basic chemical considerations ............................................................................23 3.1.1. Organoleptic assessment 23 3.1.2. Undesired effect in drinking-water preparation 24 3.1.3. Basis for calculating the guideline values 24 3.2. Selected parameters..........................................................................................25 3.2.1. Inorganics 25 3.2.2. Radioactivity 28 4. Health risks in the water system..................................................................................29 4.1. Vulnerability of the resource ..............................................................................29 4.1.1. General considerations 29 4.1.2. New water services 29 4.1.3. Groundwaters 30 4.1.4. Sources and springs 32 4.1.5. Surface water 33 4.2. Water treatment................................................................................................34 4.2.1. Basic local water treatment 35 4.2.2. Centralized water treatment 36 4.3. Vulnerability in the distribution system................................................................45 4.3.1. Compromised network integrity 45 4.3.2. Deterioration of microbial water quality 47 4.4. WSPs................................................................................................................48 4.4.1. WSP team creation 49 4.4.2. Describe the water supply system 49 4.4.3. Identify hazards and hazardous events and risks 49 4.4.4. Determine and validate control measures, reassess and prioritize risks 49 4.4.5. Develop, implement and maintain an improvement/upgrade plan 50 4.4.6. Do operational monitoring 50 4.4.7. Verify the effectiveness of the WSP 50 4.4.8. Prepare management procedures 50 4.4.9. Develop supporting programmes 50 4.4.10. Conduct periodic review 51 4.4.11. Revise after incident 51 4.4.12. Typical challenges 51 4.5. Point-of-use treatment.......................................................................................51 5. Essential epidemiology................................................................................................57 5.1. Basic definitions ................................................................................................57 5.1.1. Surveillance 57 5.1.2. Mortality 57 5.1.3. Morbidity 57 5.1.4. Prevalence and incidence 58 5.1.5. Endemic, epidemic and pandemic disease distribution 58 5.1.6. Outbreak 59 5.1.7. Population at risk 59 5.2. Basic study designs ...........................................................................................59 5.2.1. Descriptive studies 59 5.2.2. Analytical studies 60 5.3. Sources of errors in epidemiological studies ........................................................64 5.3.1. Random error 64 5.3.2. Systematic error 64 5.4. Specific methodological challenges of conducting epidemiological studies .............64 5.4.1. Study design 65 5.4.2. Exposure assessment 67 5.4.3. Measurement of health outcomes 68 5.4.4. Analysis 69 5.5. Detection, investigation and reporting of water-related disease outbreaks ............72 5.5.1. Preparation 73 5.5.2.