Temporal and geographical distributions of reported cases of Escherichia coli O157[ratio ]H7 infection in Ontario

Abstract

The distribution of 3001 cases of verocytotoxigenic Escherichia coli (VTEC) reported in the Province of Ontario, Canada, were examined to describe the magnitude of this condition geographically and to evaluate the spatial relationship between livestock density and human VTEC incidence using a Geographical Information System. Incidence of VTEC cases had a marked seasonal pattern with peaks in July. Areas with a relatively high incidence of VTEC cases were situated predominantly in areas of mixed agriculture. Spatial models indicated that cattle density had a positive and significant association with VTEC incidence of reported cases (P = 0.000). An elevated risk of VTEC infection in a rural population could be associated with living in areas with high cattle density. Results of this study suggested that the importance of contact with cattle and the consumption of contaminated well water or locally produced food products may have been previously underestimated as risk factors for this condition.

A geostatistical investigation of agricultural and infrastructural risk factors associated with primary verotoxigenicE. coli(VTEC) infection in the Republic of Ireland, 2008–2013

“…Michel et al [29] have previously observed a significantly higher incidence of VTEC O157 infection in rural areas of Ontario, while Innocent et al [30] have reported a decreasing cumulative incidence in concurrence with increasing population density in Scotland. Likewise, previous studies by Strachan et al [16] and Pearl et al [31] provide evidence of the influence of geographical location on VTEC infection incidence, with reported VTEC incidence rates 1·7-4 times greater in rural areas than in urban areas.…”

Comanaging fresh produce for nature conservation and food safety

“…Previous work also has shown that generic E. coli (18), E. coli O157:H7 (27), Salmonella (28), and Listeria (29,30) are positively associated with livestock density or proximity to livestock. Similarly, studies that have aggregated reported EHEC illnesses to county or district levels have generally observed higher EHEC infection rates in counties with higher cattle densities, although this approach infers rather than directly links cases and exposures (19,20).…”

“…More generally, our work indicates that achieving food safety and nature conservation goals in produce-growing landscapes is possible. contaminated waterways, to aggregate reported illnesses to a county or district level, and to correlate infection rates with land use patterns (19,20).…”

Transmission and control of Escherichia coli O157:H7 — A review

“…Rural residents were at an increased risk for VTEC infection. That finding may also explain the relatively high incidence of VTEC infections in Prince Edward Island, where the cattle density (0.17 per hectare) approaches that of the regions of Ontario with the highest incidence of VTEC infection (0.2 cattle per hectare; Michel et al 1999). Factors which may be associated with the increased risk include recurrent exposure to cattle, surface water and shallow well contamination with cattle manure used as fertilizer and consumption of locally processed foods .…”

“…In Canada, reports of E. coli O157:H7 infection have been more frequent in the western provinces than in the east (Griffin and Tauxe 1991;Nataro and Kaper 1998). Michel et al (1999) investigated the relative risks of VTEC infection associated with living in rural vs. urban environments by examining the geographic distribution of VTEC infections in Ontario, Canada, between 1990 and 1995. Reported annual rates of VTEC infection were consistently higher in rural areas (5.4 per 100 000) as compared to urban areas (4.4 per 100 000).…”