THE INFLUENCE OF CATTLE WASTE AND SEWAGE EFFLUENT ON THE LEVELS OF
CRYPTOSPORIDIUM OOCYSTS IN SURFACE WATERS
Report No FR0421

E G Carrington and P Gray

Dec 1993

SUMMARY

I OBJECTIVES

The objective of this study was to determine the influence of cattle-related waste upon the Cryptosporidium oocyst burden of sewage entering the treatment works and hence on surface waters.

II REASONS

The Group of Experts on Cryptosporidium in Water, chaired by Sir John Badenoch, identified sewage effluent as a potential major source of oocysts in surface waters and it is known that infected animals excrete large numbers of oocysts.

III CONCLUSIONS

The study confirmed the opinion of the Group of Experts, but for reasons beyond their control the researchers were not able to quantify the influence of large congregations of animals.

IV RESUME

Waterborne outbreaks of cryptosporidiosis have occurred as a result of oocysts passing through water treatment plants. This study has shown that where the waste from large congregations of animals enters the sewers some oocysts will pass through the sewage treatment works to the receiving water. For reasons unrelated to the study it has not been possible to quantify the influence of activities of animal traders with respect to Cryptosporidium oocysts in sewage and surface waters.

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