A multi-centre prospective case-control study of campylobacter infection in persons aged 5 years and older in Australia

There are an estimated 277 000 cases of campylobacteriosis in Australia each year, most of which are thought to be sporadically acquired. To explore causes for these infections, we conducted a multi-centre case-control study of patients and community controls across five Australian States during 2001-2002. A total of 881 campylobacter cases and 833 controls aged ≥5 years were recruited into the study. Crude logistic analyses were conducted within various food and non-food exposure groups. A final most parsimonious multivariable logistic regression model was developed and adjusted odds ratios (aOR), 95% confidence intervals (95% CI) were derived together with adjusted population attributable risks (PAR). Consumption of undercooked chicken (aOR 4.7, 95% CI 2.6-8.4) and offal (aOR 2.0, 95% CI 1.0-4.0), ownership of domestic chickens aged <6 months (aOR 12.4, 95% CI 2.6-59.3) and domestic dogs aged <6 months (aOR 2.1, 95% CI 1.1-4.2) were found to be independent risk factors for illness in the final model. The PAR proportions indicate that eating chicken meat, either cooked or undercooked may account for approximately 30% of campylobacter cases that occur each year in Australia. These results justify the continued need for education of consumers and foodhandlers about the risks associated with the handling of raw chicken and the potential for cross-contamination.