01 Nigel Silman 2016 - SWIG · 6dih gulqnlqj zdwhu lv d edvlf qhhg iru kxpdq ghyhorsphqw khdowk dqg...

$: 01 Nigel Silman 2016 - SWIG · 6dih gulqnlqj zdwhu lv d edvlf qhhg iru kxpdq ghyhorsphqw khdowk dqg zhoo ehlqj dqg ehfdxvh ri wklv lw lv dq lqwhuqdwlrqdoo\ dffhswhg kxpdq uljkw$
Waterborne Infectious Diseases

Prof. Nigel J SilmanPublic Health England Institute of Biosensing TechnologyPorton Down University of the West of EnglandSalisbury, 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 Workshop on Biosensors | 20th July 2016

Some Statistics• Diarrhoeal diseases account for 3.6% of global burden of

disease, DALY (Disability Adjusted Life Years)• This equates to 1.5 million deaths per annum• 88% of diarroheal 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 drowning


• Classical Waterborne Diseases• Cholera• Typhoid Fever• Giardia• Cryptosporidium• Indicators of Faecal Contamination• E. coli• Faecal Streptococci• Respiratory Diseases• Legionella pneumphila

Diseases of Concern


State of the Art!?• Most Probable

Number (MPN)


State of the Art!?• Membrane Filtration


State of the Art!?• Portable Approaches


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


Different Approaches?


Biomarkers“a characteristic that is objectively measured and evaluated

as an indicator of normal biological processes, pathogenicprocesses, or pharmacologic responses to a therapeuticintervention.”


Classes of Biomarker


Culture / isolation • Bacterial / viral / other?

Antigen / protein • ELISA / IF / Automated / Semi-Automated

Nucleic acids• PCR / hybridisation / sequencing / Isothermal Amplification

Pathogen Signature • Volatile Metabolites

KeyBiomarker

Types

Direct Detection

Indirect Detection

Rapid Diagnostics


CentralisedService

Point of Use

Community

Home Use

Considerations:• Rapidity / convenience• Positively affects management• Straightforward use• High PPV• Cost Effective• Throughput??

Types of POCT Devices


Direct Detection Considerations


Biomarker Technology Time to Result

POCT? Diagnostic Window

SensitivityIsolation of Pathogen

Culture days No Variable Med/HighAntigen Immuno-

assaymins -hours

Yes Variable LowNucleic Acids

PCR / Sequencing / NAAT

mins -hours

Maybe Variable High

Metabolites Various Mins –hours

Maybe Variable Low / Med

But, all water samples would need concentration

Antibody / Antigen Biomarkers


Nucleic Acids


Nucleic Acid Amplification


• Relies on absolute fidelity between primer, probe & target

• PCR needs a thermocycler – not that portable!

Volatile Organic Metabolites


• Pathogen & host metabolites

• Host breath analysis• “Fingerprinting”

Summary


01 Nigel Silman 2016 - SWIG · 6dih gulqnlqj zdwhu lv d edvlf qhhg iru kxpdq ghyhorsphqw khdowk dqg...

Documents

Transcript of 01 Nigel Silman 2016 - SWIG · 6dih gulqnlqj zdwhu lv d edvlf qhhg iru kxpdq ghyhorsphqw khdowk dqg...