Foodborne botulism in Canada, 1985-2005

Abstract

During 1985-2005, a total of 91 laboratory-confirmed outbreaks of foodborne botulism occurred in Canada; these outbreaks involved 205 cases and 11 deaths. Of the outbreaks, 75 (86.2%) were caused by Clostridium botulinum type E, followed by types A (7, 8.1%) and B (5, 5.7%). Approximately 85% of the outbreaks occurred in Alaska Native communities, particularly the Inuit of Nunavik in northern Quebec and the First Nations population of the Pacific coast of British Columbia. These populations were predominantly exposed to type E botulinum toxin through the consumption of traditionally prepared marine mammal and fish products. Two botulism outbreaks were attributed to commercial ready-to-eat meat products and 3 to foods served in restaurants; several cases were attributed to non-Native home-prepared foods. Three affected pregnant women delivered healthy infants. Improvements in botulism case identification and early treatment have resulted in a reduction in the case-fatality rate in Canada.

Keywords: Canada; Clostridium botulinum; antitoxin; botulism; foodborne infections; outbreak; serotype; type E botulinum toxin.

Figure 1

Number of cases of foodborne botulism and disease incidence (rate/100,000 population), Canada, 1985–2005.

Figure 2

Distribution of outbreaks of foodborne botulism by serotype, Canada, 1985–2005. Circles represent type E outbreaks, triangles type A outbreaks, pentagons type B outbreaks, and squares outbreaks of unknown serotype. Circle sizes are proportionate to the number of outbreaks occurring in a given location.