A time series analysis of the relationship of ambient temperature and common bacterial enteric infections in two Canadian provinces
- 790 Downloads
The incidence of enteric infections in the Canadian population varies seasonally, and may be expected to be change in response to global climate changes. To better understand any potential impact of warmer temperature on enteric infections in Canada, we investigated the relationship between ambient temperature and weekly reports of confirmed cases of three pathogens in Canada: Salmonella, pathogenic Escherichia coli and Campylobacter, between 1992 and 2000 in two Canadian provinces. We used generalized linear models (GLMs) and generalized additive models (GAMs) to estimate the effect of seasonal adjustments on the estimated models. We found a strong non-linear association between ambient temperature and the occurrence of all three enteric pathogens in Alberta, Canada, and of Campylobacter in Newfoundland-Labrador. Threshold models were used to quantify the relationship of disease and temperature with thresholds chosen from 0 to −10°C depending on the pathogen modeled. For Alberta, the log relative risk of Salmonella weekly case counts increased by 1.2%, Campylobacter weekly case counts increased by 2.2%, and E. coli weekly case counts increased by 6.0% for every degree increase in weekly mean temperature. For Newfoundland-Labrador the log relative risk increased by 4.5% for Campylobacter for every degree increase in weekly mean temperature.
KeywordsFoodborne disease Ambient temperature Time series analysis Climate change Canada
We thank Alberta Public Health and Newfoundland and Labrador Centre for Health Information for the use of their notifiable disease data for this study. We also thank the cCASHh study for their support and collaboration and James R. Ferguson, a geographical consultant, for preparing the map for this article.
- Aramini J, McLean M, Wilson J et al (2000) Drinking water quality and health care utilization for gastrointestinal illness in greater Vancouver. Health Canada: Population and Public Health Branch. OctoberGoogle Scholar
- Canadian Integrated Surveillance Report (2003) Salmonella, Campylobacter, pathogenic E. coli and Shigella, from 1996–1999. Canadian Communicable Disease Report 2951Google Scholar
- Canadian Medical Association Journal (2003) Food irradiation: Let’s do it (editorial). Can Med Assoc J 162:5Google Scholar
- Environment Canada (2002) “The Climate of Newfoundland.” The Green Lane (Dartmouth, Nova Scotia) http://www.atl.ec.gc.ca/climate/nfld.html)
- Hastie TJ, Tibshirani R (1990) Generalized additive models. Chapman and Hall, LondonGoogle Scholar
- Mathsoft (1999) S-PLUS 2000 guide to statistics, vol 1. Data Analysis Products Division, Mathsoft, Seattle, WAGoogle Scholar
- Statistics Canada (2002) Population and dwelling counts, for Canada, Provinces and Territories, 2001 and 1996 censuses. Statistical Reference Centre, Ottawa, ON, http://www12.statcan.ca/english/census01/products/standard/popdwell/Table-PR.cfm)