Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2005 Sep 16:5:72.
doi: 10.1186/1471-2334-5-72.

Population-based laboratory surveillance for Giardia sp. and Cryptosporidium sp. infections in a large Canadian health region

Kevin B Laupland  1 , Deirdre L Church
Affiliations

Population-based laboratory surveillance for Giardia sp. and Cryptosporidium sp. infections in a large Canadian health region

Kevin B Laupland et al. BMC Infect Dis. .

Abstract

Background: Giardia lamblia (intestinalis) and Cryptosporidium parvum are the two most important intestinal parasites infecting North Americans but there is a paucity of active population-based surveillance data from Canada. This study determined the incidence of and demographic risk factors for developing Giardia sp. and Cryptosporidium sp. infections in a general Canadian population.

Methods: Population-based laboratory surveillance was conducted among all residents of the Calgary Health Region (CHR; population approximately = 1 million) during May 1, 1999 and April 30, 2002.

Results: Giardia sp. infection occurred at a rate of 19.6 per 100,000 populations per year. Although the yearly incidence was stable, a significant seasonal variation was observed with a peak in late summer to early fall. Males were at higher risk for development of this infection as compared to females (21.2 vs. 17.9 per 100,000/yr; relative risk (RR) 1.19; 95% confidence interval (CI), 1.00-1.40, p = 0.047), and there was a significant decrease in risk associated with an increasing age. Cryptosporidium sp. infection occurred at an overall rate of 6.0 per 100,000 populations per year although a large outbreak of Cryptosporidium sp. infections occurred in the second half of the summer of 2001. During August and September of 2001, the incidence of cryptosporidiosis was 55.1 per 100,000 per year as compared to 3.1 per 100,000 per year for the remainder of the surveillance period (p < 0.0001). Cryptosporidiosis was largely a disease of children with an incidence of 17.8 per 100,000 per year occurring among those aged < 20 years of age compared to 1.25 per 100,000 per year for adults > or = 20 years of age (RR 14.19; 95% CI, 9.77-21.11; p < 0.0001).

Conclusion: This study provides important information on the occurrence and demographic risk groups for acquisition of giardiasis and cryptosporidiosis in a non-selected Canadian population.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Seasonal distribution of Giardia sp. infections in the Calgary Health Region.
Figure 2
Figure 2
Age and gender specific incidence rates of Giardia sp. infection in the Calgary Health Region.
Figure 3
Figure 3
Occurrence of infections with Cryptosporidium sp. in the Calgary Health Region.
Figure 4
Figure 4
Age and gender specific incidence rates of Cryptosporidium sp. infection in the Calgary Health Region.
See this image and copyright information in PMC

References

    1. Furness BW, Beach MJ, Roberts JM. Giardiasis surveillance – United States, 1992–1997. MMWR CDC Surveill Summ. 2000;49:1–13. - PubMed
    1. Croll NA, Gyorkos TW. Parasitic disease in humans: the extent in Canada. Can Med Assoc J. 1979;120:310–2. - PMC - PubMed
    1. Odoi A, Martin SW, Michel P, Holt J, Middleton D, Wilson J. Determinants of the geographical distribution of endemic giardiasis in Ontario, Canada: a spatial modelling approach. Epidemiol Infect. 2004;132:967–76. doi: 10.1017/S0950268804002481. - DOI - PMC - PubMed
    1. Welch TP. Risk of giardiasis from consumption of wilderness water in North America: a systematic review of epidemiologic data. Int J Infect Dis. 2000;4:100–3. doi: 10.1016/S1201-9712(00)90102-4. - DOI - PubMed
    1. Yoder JS, Blackburn BG, Craun GF, Hill V, Levy DA, Chen N, Lee SH, Calderon RL, Beach MJ. Surveillance for waterborne-disease outbreaks associated with recreational water – United States, 2001–2002. MMWR Surveill Summ. 2004;53:1–22. - PubMed

MeSH terms