WSAASTRATEGIC WORKSHOP ON VIABILITY TESTING

ANDGENETIC TYPING OF CRYPTOSPORIDIUM OOCYSTS

OccasionalPaper WSAA No 4

March 2000

The WaterServices Association of Australia has developed a research strategy to addressthe issue of Cryptosporidium in watersupplies. The research strategy is dynamic and continues to evolve as moreknowledge and experience build up.

The strategicworkshop held on the 9^th and 10^th of March 2000 wassponsored by WSAA to further define research strategies in the areas of:

·        Viabilitymeasurement (capability of infecting a human); and

·        Genetictyping as a tool for use in genotyping (strain identification) and molecularepidemiology (tracking transmission) of Cryptosporidial infections.

Reliablemeasurement of the viability of oocysts is vital in evaluating preventivestrategies to inactivate the oocysts. Such a viability test could be used tocompare the viability of oocysts subject to a range of environmentalconditions, storage in water and exposure to disinfectants either before, orafter environmental exposure. Development of guidelines setting out theconditions required to inactivate oocysts would be an outcome of the research.

Predictiveepidemiology is vital to medically based hazard analysis. Is the particularhazard, in this case, Cryptosporidium significantor not to public health? Early detection and management of any outbreaks isalso based on predictive epidemiology. Genotyping and ultimately geneticfingerprinting are essential tools in molecular epidemiology. Improved hazardanalysis, health surveillance and incident management would be another outcomeof the research.

The jointworkshop sponsored by The Drinking Water Inspectorate, UKWIR, AWWARF, and WSAAWorkshop held in the UK at Tadley Court concluded that human cell culture  represented the best option for reliablemeasurement of oocyst viability. The techniques for the use of cell culture,cell lines and media components are well established for the cattle genotype(Genotype 2) oocysts but not as well established for human (Genotype 1)oocysts.

WSAA thereforesponsored this March 2000 workshop to follow up the findings of Tadley Court,introduce the technique of human cell culture to Australia (particularly forthe human geneotype) and stimulate multi laboratory collaborative initiativesto accelerate research.

Copiesof the Report are available from WSAA, price $A20. Orders may be placed throughthe Bookshop at www.wsaa.asn.au or by email to info@wsaa.asn.au.