Epidemiology and Infection

Case-control studies of sporadic cryptosporidiosis in Melbourne and Adelaide, Australia

B.  ROBERTSON  a1, M. I.  SINCLAIR  a1 c1, A. B.  FORBES  a1, M.  VEITCH  a2, M.  KIRK  a3, D.  CUNLIFFE  a4, J.  WILLIS  a1 and C. K.  FAIRLEY  a5
a1 Cooperative Research Centre for Water Quality and Treatment at Department of Epidemiology and Preventive Medicine, Monash University, Alfred Hospital, Prahran, Victoria 3181, Australia
a2 Microbiological Diagnostic Unit, Department of Microbiology and Immunology, University of Melbourne, Australia
a3 OzFoodNet, Australia New Zealand Food Authority
a4 Department of Human Services, South Australia
a5 Department of Public Health, University of Melbourne, Australia


Few studies have assessed risk factors for sporadic cryptosporidiosis in industrialized countries, even though it may be numerically more common than outbreaks of disease. We carried out case-control studies assessing risk factors for sporadic disease in Melbourne and Adelaide, which have water supplies from different ends of the raw water spectrum. In addition to examining drinking water, we assessed several other exposures. 201 cases and 795 controls were recruited for Melbourne and 134 cases and 536 controls were recruited for Adelaide. Risk factors were similar for the two cities, with swimming in public pools and contact with a person with diarrhoea being most important. The consumption of plain tap water was not found to be associated with disease. This study emphasizes the need for regular public health messages to the public and swimming pool managers in an attempt to prevent sporadic cryptosporidiosis, as well as outbreaks of disease.

(Accepted January 11 2002)

c1 Author for correspondence.