Waterborne Diseases · Waterborne Diseases Prof. Nigel J Silman Public Health England Institute of...

Waterborne Diseases

Prof. Nigel J Silman

Public Health England Institute of Biosensing Technology

Porton Down University of the West of England

Salisbury, SP4 0JG Bristol, BS16 1QY

Safe drinking-water is a basic need for

human development, health and well-

being, and because of this it is an

internationally accepted human right

(WHO, 2001).

2 Waterborne Diseases | SWIG Water & Health | 31st January 2018

Some Statistics

• Diarrhoeal diseases account for over 3.6% of global burden

of disease, DALY (Disability Adjusted Life Years)

• This equates to 2 million deaths per annum (WHO), majority

in under 5 year olds

• 88% of diarrhoeal diseases worldwide are linked to unsafe

water supplies

• This does not include diseases where water has a

component in the infectious disease cycle

• e.g. Schistosomiasis (water stage in life-cycle)

• Malaria (vectors replicate in stagnant water)

• Chemical intoxication

• Recreationally related deaths due to drowning3 Waterborne Diseases | SWIG Water & Health | 31st January 2018

Some Visual Statistics


Some Statistics Closer to Home!

• ECDC report low numbers of waterborne disease outbreaks

(typically ‘teens)

• This is an underestimation


CAWST (Centre for Affordable Water and Sanitation Technology)

• For example, in 2006, 17

outbreaks, 3952 patients,

181 hospitalised

• Causes: erratic and

extreme rainfall

(including low rainfall)

• Flooding (yes!) in UK,

Finland, Czech Rebublic

& Sweden

• Classical Waterborne Diseases

• Cholera

• Typhoid Fever

• Giardia

• Cryptosporidium

• Indicators of Faecal Contamination

• E. coli

• Faecal Streptococci

• Respiratory Diseases

• Legionella pneumphila

Key Diseases of Concern


Case Studies:

The Public Health Problem in Gaza


• >90% of water in Gaza classified as

“unsuitable for human consumption”

• Increasing salinity in groundwater

• Contamination with pesticides, fertilisers,

sewage, heavy metals & solid waste

• HEALTH RISKS:

• Infectious disease

• High nitrate content

• Salinity

Water Sources in Gaza

• Groundwater:

• Aquifers

• Main water source

• Artesian wells & springs

• Surface Water:

• River(s) (Jordan River)

• More saline towards Dead Sea

• Wadis

• Seasonal reservoirs


Current Testing Regimen

9

• Aquifer Testing• Two samples per annum from each well (Spring & Autumn)

• No microbiology

• Desalinated Water• Known bacteriological contamination

• Little mandated testing undertaken

• Known contamination of pipes, nozzles, storage tanks etc.

• Bottled Water• 3 random samples per annum

• 50% bottled waters had high bacterial counts

Waterborne Diseases | SWIG Water & Health | 31st January 2018

Case Studies:

An Unusual Waterborne Disease


47 heater-cooler units across 13 different NHS Trusts

HPC: ranged from < 100 cfu/L - 3 x 109 cfu/L (mean = 108)

Mycobacteria spp recovered from water taken from 35/47 HCUs (74%)

Legionella spp detected in water taken from 4/5 HCUs

Case Studies:



Case Studies:



3T HCU (2002) – out of active service

Water microbiology

HPC: mean ~4 x 108 cfu/L (n=10)

range of common waterborne organisms

including a number of opportunistic pathogens:

Sphingomonas paucimobilis

Stenotrophomonas maltophilia

Brevundimonas vesicularis

M. chimaera was also present

(as was Legionella pneumophila!)

Diagnostic Approaches


State of the Art?

• Membrane Filtration


Portable Approaches


• Total coliforms

• Faecal coliforms

• Faecal Streptococcus spp.

• Na

• K

• Ca

• Mg

• Sulphate

• Nitrate

• Chloride

• TDS

• Heavy metals

Routine chemical & microbiological parameters:

Rapid Diagnostics

16

Centralised

Service

Point of Use

Community

Home Use

Considerations:

• Rapidity / convenience

• Positively affects management

• Straightforward use

• High PPV

• Cost Effective

• Throughput??


Antibody / Antigen Biomarkers


Nucleic Acid Amplification

18

• Relies on absolute fidelity between

primer, probe & target

• PCR needs a thermocycler – not that

portable!


Legionella Detection by PCR


Summary


Waterborne Diseases · Waterborne Diseases Prof. Nigel J Silman Public Health England Institute of...

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