The paper in Foodborne Pathogens and Disease provides a picture of which foodborne pathogens are causing the most illnesses in Canada and estimates the number of illnesses without a known cause.
The researchers estimate each year that there are 1.6 million (90% Credible Interval: 1.2–2 million) episodes of domestically acquired foodborne illness related to 30 specified pathogens.
They added that there are believed to be 2.4 million (90%CrI: 1.8–3 million) episodes of domestically acquired foodborne illness related to unspecified agents, bringing the total to 4 million.
The US Centers for Disease Control and Prevention (CDC) estimates that each year roughly 1 in 6 Americans get sick, 128,000 are hospitalized and 3,000 die of foodborne diseases.
Study findings
The top pathogen causing domestically acquired illness was Norovirus with 65%, said the Public Health Agency of Canada (PHAC).
Although illnesses were down from the 2008 study the researchers said the estimates cannot be compared accurately due to the different methodologies.
Data from the Canadian Notifiable Disease Surveillance System (CNDSS) and National Enteric Surveillance Program (NESP) reported no significant change in the rate of salmonella infection.
O157 Verotoxigenic Escherichia coli (VTEC) infections decreased 68% and campylobacteriosis was down 35% in 2011 compared to the 1998-2000 baseline period.
The modelling approaches were laboratory-confirmed cases of pathogens scaled up to account for under ascertainment due to under diagnosis and under-reporting.
The other was models that started with the total Canadian population and used incidence data to scale down the estimated number of illnesses.
The data used was based on the 2000-2010 time period, and the 2006 Canadian Census was the referent population, so the estimates are based circa the year 2006.
Pathogens identified
The pathogens that cause the greatest number of illnesses are norovirus (1 million), C. perfringens (177,000), Campylobacter spp. (145,000), and nontyphoidal Salmonella spp. (88,000).
Norovirus, Clostridium perfringens, Campylobacter spp., and nontyphoidal Salmonella spp. account for 90% of the pathogen-specific total.
Hepatitis A (271 illnesses), Listeria Monocytogenes (178) and Clostridium botulinum (14) ranked 24th, 25th and 28th respectively.
Unspecified agents are the main contributor to the total estimate of domestically acquired foodborne illnesses.
The use of population surveys on self-reported illness and care-seeking behaviours related to Acute gastrointestinal illness (AGI) is a potential limitation, said the study.
The objective of the analysis was to estimate domestically acquired, foodborne illness in Canada, while identifying data gaps and areas for further research.
Source: FOODBORNE PATHOGENS AND DISEASE
Online ahead of print, DOI: 10.1089/fpd.2012.1389
“Estimates of the Burden of Foodborne Illness in Canada for 30 Specified Pathogens and Unspecified Agents, Circa 2006”
Authors: M. Kate Thomas, Regan Murray, Logan Flockhart, Katarina Pintar, Frank Pollari, Aamir Fazil, Andrea Nesbitt, and Barbara Marshall