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Interdisciplinary Perspectives on Infectious Diseases
Volume 2011, Article ID 341065, 6 pages
Research Article

A Community Outbreak of Cryptosporidiosis in Sydney Associated with a Public Swimming Facility: A Case-Control Study

1South Eastern Sydney Illawarra Public Health Unit, Health Reform Transition Organisation—Southern, Locked Mail Bag 9, Wollongong, NSW 2526, Australia
2South Eastern Sydney Illawarra Public Health Unit, Health Reform Transition Organisation—Southern, Locked Bag 88, Randwick, NSW 2031, Australia
3School of Public Health and Community Medicine, Faculty of Medicine, University of New South Wales, Level 2 and 3 Samuels Building, UNSW Sydney, 2052 NSW, Australia
4School of Medicine Sydney, University of Notre Dame Australia, 160 Oxford Street, Darlinghurst NSW 2010, Australia

Received 27 September 2011; Accepted 29 November 2011

Academic Editor: Dinesh Mondal

Copyright © 2011 Darren J. Mayne et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


In February, 2008, the South Eastern Sydney Illawarra Public Health Unit investigated an outbreak of cryptosporidiosis within the south east region of Sydney, Australia. Thirty-one cases with laboratory-confirmed cryptosporidiosis and 97 age- and geographically matched controls selected by random digit dialling were recruited into a case-control study and interviewed for infection risk factors. Cryptosporidiosis was associated with swimming at Facility A (matched odds ratio = 19.4, 95% confidence interval: 3.7–100.8) and exposure to household contacts with diarrhoea (matched odds ratio = 7.7, 95% confidence interval: 1.9–31.4) in multivariable conditional logistic regression models. A protective effect for any animal contact was also found (matched odds ratio = 0.2, 95% confidence interval: 0.1–0.7). Cryptosporidium hominis subtype IbA10G2 was identified in 8 of 11 diagnostic stool samples available for cases. This investigation reaffirms the importance of public swimming pools as potential sources of Cryptosporidium infection and ensuring their compliance with water-quality guidelines. The protective effect of animal contact may be suggestive of past exposure leading to immunity.