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

S. Typhi and S. Paratyphi Cases

The number of S. Typhi and S. Paratyphi (including S. Paratyphi A, B and C) infections reported from 2000 to 2004 are shown in Table 7. An increase in cases was observed for both serovars over the five-year period. Since S. Typhi and S. Paratyphi are not endemic in Canada, this increase reflects travel to endemic countries by Canadians^(9,13). Paratyphoid fever (S. Paratyphi infections) was removed from the national notifiable disease list in 1999, consequently, there can be no data comparison with the NESP data from 2000 onward.

The national rate of S. Typhi infections from 1995 to 2004 remained stable except for a sharp

decrease from 1997 to 1999 (Figure 12). The number of S. Typhi cases recorded in the NESP database was slightly higher than in the NDRS database.

* Includes S. Paratyphi A, Paratyphi B & B var. Java & Paratyphi C (1 case in QC in 2001 only).

Figure 12: Reported rates of S. Typhi cases (per 100,000 population), 1995 to 2004*

NML/NESP data includes totals from the NML (1995-1997) and NESP (1998-2004).

The seasonal trend of reported cases of S. Typhi from 2000 to 2004 shows distinct peaks throughout the spring and early fall seasons (Figure 13).

Although S. Typhi totals increased in both the NESP and NDRS databases throughout this period, there was considerable variation in provincial totals between the two databases.

Figure 13: Reported rates of S. Typhi by month, 2000 to 2004, NDRS and NESP

Figures 14 and 15 show the annual rate in each province and territory for S. Typhi and S. Paratyphi from 2000 to 2004. There is considerable variation within and among provinces/territories, with the highest rates occurring in British Columbia. An increase in S. Typhi isolations in British Columbia in early 2003 led to an investigation which confirmed that many of these infections were linked to travel to the state of Punjab, India. The overall increase of S. Paratyphi was due to increased number of cases reported in Ontario and British Columbia (Figure 15). Prince Edward Island reported one case of S. Typhi and three S. Paratyphi over the five year period, which resulted in high provincial rates of infection due to the small population size. No cases of S. Typhi and S. Paratyphi were reported for the territories.

Figure 14: Reported rate of S. Typhi infections (per 100,000 population) by province/territory, 2000 to 2004, NESP

Figure 15: Reported rate of S. Paratyphi infections (per 100,000 population) by province/territory, 2000 to 2004, NESP

A history of travel was provided for 47 cases of S. Typhi and S. Paratyphi reported to the NESP from 2000 to 2004. During this period, only 25 of the 563 S. Typhi, and 22 of the total 581 S. Paratyphi cases reported were identified as travel-related, although the majority of these were likely related to foreign travel since S. Typhi and S. Paratyphi are not endemic in Canada. Travel to Asia accounted for 96% (45/47) of all S. Typhi and S. Paratyphi cases for which history of travel was provided to the NESP (Table 8). Approximately 56% (291/519) of typhoid fever (S. Typhi) cases reported to the NDRS were identified as travel-related with travel to Asia, Africa, Central America and South America being reported.