ARCHIVED - Canadian Integrated Surveillance Report: Salmonella, Campylobacter, verotoxigenic E. coli and Shigella, from 2000 to 2004

Human Salmonella Cases

Between 2001 and 2004, there was an overall decrease in Salmonella cases reported in Canada, with 2003 and 2004 numbers being well below the level reported in 2000 (Table 1). This decline is seen in all provinces and territories, with the exception of New Brunswick (Figure 1). The low number of reported cases and smaller population base in the three territories results in greater trend variability. The two key national surveillance systems that capture information on enteric disease, the National Notifiable Disease Reporting Systems database (NDRS) and the National Enteric Surveillance Program (NESP), show a high degree of concurrence during this period. This level of agreement is expected given the high frequency with which local laboratories forward Salmonella isolates to their provincial or central reference laboratory for serotyping. For a description of the NDRS and NESP, please refer to Appendix A – Section 1 and 2.

Figure 1: Rates of salmonellosis (per 100,000 population) as reported to the National Notifiable Disease Summary program (NDRS) and the National Enteric Surveillance Program (NESP) by province/territory, 2000 to 2004*

* Note the different scale used for Nunavut.

Top 10 Serovars

The top 10 Salmonella serovars reported to the NESP from 2000 to 2004 are listed in Table 2. S. Typhimurium remained the most frequently reported serovar over the five-year period, while the second and third positions alternated between S. Heidelberg and S. Enteritidis. This list of most common serovars remained consistent during the period under review. Only three of the serovars recorded were not among the top 10 every year: S. Oranienburg, S. Saintpaul and S. ssp I 4,[5],12:i:-. Most of the S. Oranienburg cases reported in 2002 were linked to a multi-provincial outbreak.

* A multi-provincial S. Oranienburg outbreak was identified in 2002.

Note: The analysis of human Salmonella data presented in the remainder of this report is divided into non-typhoid Salmonella and S. Typhi/ Paratyphi. S. Typhi and S. Paratyphi are host adapted serovars which primarily causes invasive infection, while the primary presentation of nontyphoid Salmonella (non-host adapted species) is enteric (salmonellosis).