WSAA STRATEGIC WORKSHOP ON VIABILITY TESTING

AND GENETIC TYPING OF CRYPTOSPORIDIUM OOCYSTS

Occasional Paper WSAA No 4

March 2000

 

 

The Water Services Association of Australia has developed a research strategy to address the issue of Cryptosporidium in water supplies. The research strategy is dynamic and continues to evolve as more knowledge and experience build up.

 

The strategic workshop held on the 9^th and 10^th of March 2000 was sponsored by WSAA to further define research strategies in the areas of:

 

·         Viability measurement (capability of infecting a human); and

 

·         Genetic typing as a tool for use in genotyping (strain identification) and molecular epidemiology (tracking transmission) of Cryptosporidial infections.

 

Reliable measurement of the viability of oocysts is vital in evaluating preventive strategies to inactivate the oocysts. Such a viability test could be used to compare the viability of oocysts subject to a range of environmental conditions, storage in water and exposure to disinfectants either before, or after environmental exposure. Development of guidelines setting out the conditions required to inactivate oocysts would be an outcome of the research.

Predictive epidemiology is vital to medically based hazard analysis. Is the particular hazard, in this case, Cryptosporidium significant or not to public health? Early detection and management of any outbreaks is also based on predictive epidemiology. Genotyping and ultimately genetic fingerprinting are essential tools in molecular epidemiology. Improved hazard analysis, health surveillance and incident management would be another outcome of the research.

The joint workshop sponsored by The Drinking Water Inspectorate, UKWIR, AWWARF, and WSAA Workshop held in the UK at Tadley Court concluded that human cell culture  represented the best option for reliable measurement 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 therefore sponsored this March 2000 workshop to follow up the findings of Tadley Court, introduce the technique of human cell culture to Australia (particularly for the human geneotype) and stimulate multi laboratory collaborative initiatives to accelerate research.

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