Water Services National Training Group and National Federation of Group Water Schemes

Water Services National Training Group and

National Federation of Group Water Schemes

7th Annual Rural Water Services Conference

18th September 2008

Safety & Security of Water Supplies- A Public Health Issue

Dr. Heidi Pelly,

Consultant, Public Health Medicine,

Health Services Executive

Terminology

• A pathogen is a microorganism capable of causing disease in a host

• Waterborne pathogens excreted in faeces of humans/animals, transmitted via ingestion

• Water-based pathogens occur naturally in water, usually not transmitted person to person (e.g. Legionella spp.)

Importance of Waterborne Pathogens

• Increased sensitive subpopulations

• Recognition of important additional health effects, including chronic sequelae

• Natural evolution of microbes with increased virulence

• Development of molecular techniques leading to improvements in detection of outbreaks and their sources.

Agents of Waterborne or Water-based Disease

• Bacteria:

Shigella spp.

Toxigenic E. coli

Campylobacter spp• Viruses:

Norovirus

Rotavius

Hepatitis A• Protozoa:

Cryptosporidium spp

Giardia

Toxoplasma Gondi

•Waterborne outbreaks generally caused by failed/absent treatment processes

•Greatest infectivity, small dose cause infection, longer environmental survival. Removal by filtration inefficient, more resistant to disinfection.

•Single cell organism, thick wall highly resistant to disinfection

Landmark Water Incidents

• International– Soho 1854 – Cholera

outbreak ( John Snow)– Hamburg 1892 –

Cholera epidemic– Swinden 1989 –

Cryptosporidium– Milwaukee 1993 –

Cryptosporidium– Walkerton – E. coli

•National- Naas 1992

- Nenagh 1996

- Mullingar 2002

- Galway 2007

Current Situation

• 944 Public water supplies

• 777 Public group water schemes (GWS)

• 706 Private GWS

• 100,000 – 200,000 Private wells

• 85% surface water

• Increasing demand

Legislation

Water Services Act 2007

• ‘protection of human health’

• ‘protection of public health’

• ‘public authority’ includes Health Service Executive

• ‘water services authority’ replaces ‘sanitary authority’

Drinking Water RegulationsS.I. No. 278 of 2007Protection of human health

– Para 9 (1) Where a sanitary authority, in consultation with the HSE, considers that a supply of water intended for human consumption constitutes a potential danger to human health, the authority shall, subject to agreement with the HSE, ensure that …..

– Para 9 (2) …. Subject to agreement with the HSE … the supervisory authority shall issue such direction to the relevant water supplier as it considers necessary….

Drinking Water Regulations S.I. No. 278 of 2007Departures from standards

– Para 11 (1) A departure from the parametric values…. may …. subject to the agreement of the HSE, be granted by the Agency……

Confirmed in writing by the Medical Officer of Health (EPA Handbook)

Infectious Disease RegulationsS.I. No. 390 of 1981• Para 11 On becoming aware … of a case or a

suspected case of an infectious disease or of a probable source of infection with such disease, a medical officer of health… shall make such enquiries and take such steps as are necessary … for investigating the nature and source of infection, for preventing the spread of such infection and for removing conditions favourable to such infection

Other Relevant Legislation

• Food safety– Food Hygiene Regulation S.I. No. 205 of 1950– EC Regulation No 852/2004

• hygiene of foodstuffs • requires the use of potable water in connection

with the food business• S.I. No. 369 of 2006 gives effect in Irish law

• Fluoridation Regulations S.I. No. 42 of 2007

Current Procedures

• Routine

- Water Liaison Group

- Protocols/guidelines

- Water monitoring programme

- Surveillance of notifiable disease

•Incidence Response Team-Water monitoring results

-Acute infections

-Increase/outbreak of human illness

Environmental Health Service

• First point of contact with HSE

• Water monitoring programme for local authorities

• Water monitoring under food safety legislation

• Fluoridation (Dentists)

• Environmental expertise

Laboratory Services

• Clinical Laboratories

- Patient specimens

• Public Health Laboratories

- Water & environmental specimens

• Public Analyst Laboratories

• Reference Laboratories

• Consultant microbiologist

Public Health Department

• Surveillance of notifiable infectious disease

- Receive notifications

- Enhanced surveillance

- case finding

- HPSC

• Investigation

- Epidemiological studies – descriptive/analytical

- International evidence

- Expert advice

• Staff

- Public Health Doctors – MOH

- Surveillance Scientists

- Communicable Disease Nurse

Public Health Advice

• Health and other professionals

• Vulnerable groups

- Immunocompromised

- Infants

- Elderly

• General public

• Risk Communication

Health Protection Surveillance Centre

• Collate date on notifiable infections at national level

• Support preparation of national guidelines/advice/IT systems e.g. CIDR

• Monitors trends

• Annual reports. e.g.Annual report of HPSC 2002

•7/64 outbreaks associated with suspect waterborne or waterborne combined with other route of transmission

•However, these outbreaks contributed to over 40% reported cases of infectious intestinal disease

Protection Of Human Health

• Assessment of the risk

- Is there a problem

- what is the cause

• Identification of the population affected

- Vulnerable groups

- Vulnerable sites

• What can be done now• What can be done to stop it happening again

Boil Water Notice

• Advantages – immediate and effective• Disadvantages

- Compliance

- Duration

- Criteria for lifting

- Resources

- Burns/scalds

- Alternative supplies

- Loss of confidence

Critical Review of Waterborne Disease Outbreaks.

Hrudley and Hrudley 2007Cryptosporidium, 20

Campylobacter, 14

Giardia, 13

Norovirus, 12

Pathogenic E. Coli, 7

Unidentified, 5

Rotavirus, 2

Shigella, 2

Hepatitis A 1

Salmonella 1

Toxoplasmosis 1

Factors contributing to these outbreaks

• Wastewater contamination• Inadequate knowledge of source water hazards• Inadequate disinfection• Extreme weather (heavy rain & runoff)• Filtration failures• Cross-connections and distribution failures• Livestock/wildlife faecal contamination• Plant maintenance/treatment process changes

Factors contributing to outbreak failures• “More than one mechanism was involved in

contributing to each outbreak, and vulnerable conditions had often been in place for years, if not decades. In hindsight, all of these outbreaks were preventable, often with even a modest level of foresight and care.”

• “ The preventive measures required are all things that we know how to do.”

Relying on Microbiological Evidence of Disease

• Asymptomatic disease• An infected person may not visit doctor• The doctor may not seek a stool specimen• The patient may not provide a specimen• The appropriate test may not be requested• The test may be done incorrectly• The test may be unable to detect pathogens

present• There may be delays in laboratory reporting.

The World’s Water SupplyIf all earth’s water fit in a gallon

jug, available fresh water would equal just over a tablespoon – less than half of one percent of the total. About 97 percent of the planet’s water is seawater and another 2 percent is locked in icecaps and glaciers. Vast reserves of fresh water underlie earth’s surface, but much of it is too deep to economically tap.

References

• Hrudley, S. E; Hrudley, E. J. (2007) Published Case Studies of Waterborne Disease Outbreaks – Evidence Of a Recurrent Threat. Critical Review. Water Environment Research, 79 (3), 233 – 245.

Acknowledgments

• Dr. BethAnn Roch, HSE South (SE).

• Dr Tessa Greally, HSE West (MW)

Water Services National Training Group and

National Federation of Group Water Schemes

7th Annual Rural Water Services Conference

18th September 2008