Determining Relationships Between the Seasonal Occurrence ofEscherichia coliO157:H7 in Live Cattle, Ground Beef, and Humans

Abstract

The prevalence and concentration of many foodborne pathogens exhibit seasonal patterns at different stages of the farm-to-table continuum. Escherichia coli O157:H7 is one such pathogen. While numerous studies have described the seasonal trend of E. coli O157:H7 in live cattle, ground beef, and human cases, it is difficult to relate the results from these different studies and determine the interrelationships that drive the seasonal pattern of beef-related human illnesses. This study uses a common modeling approach, which facilitates the comparisons across data sets, to relate prevalence in live cattle to raw ground beef and human illness. The results support an intuitive model where a seasonal rise of E. coli O157:H7 in cattle drives increased ground beef prevalence and a corresponding rise in the human case rate. We also demonstrate the use of these models to assess the public health impact of consumer behaviors. We present an example that suggests that the probability of illness, associated with summertime cooking and handling practices, is not substantially higher than the baseline probability associated with more conventional cooking and handling practices during the remainder of the year.

Temporal patterns of Campylobacter contamination on chicken and their relationship to campylobacteriosis cases in the United States

“…The NPST test chooses a 6-month long significant seasonal increase running from May through October (p = 0.013). This seasonal increase is very similar, in terms of both onset and duration, to the seasonal increases in illness observed in FoodNet for Salmonella and E. coli O157:H7 (Williams et al, 2010(Williams et al, , 2014.…”

“…For example, ground beef has been implicated in the majority of the E. coli O157:H7 related outbreaks in the United States and this product-pathogen pair has the highest estimated attribution fraction (Painter et al, 2013). A time series analysis for E. coli O157:H7, using methods similar to those employed here, demonstrated a nearly perfect correspondence in the seasonal patterns between live cattle, ground beef and human illnesses (Williams et al, 2010). A similarly strong seasonal pattern between chicken and campylobacteriosis cases has been observed in Iceland (Lowman et al, 2009;Tustin et al, 2011), where a substantial reduction in campylobacteriosis cases was observed after an aggressive control program was implemented to reduce Campylobacter contamination of chicken.…”

“…Specifically, if poultry is the primary vehicle, we would expect to observe seasonal patterns of similar shape and magnitude and with the seasonal rise in poultry contamination preceding, or coincident with, a rise in human campylobacteriosis cases. These types of seasonal patterns have been observed for Campylobacter (Jore et al, 2010) and in Escherichia coli O157:H7 contamination in the food chain from live animals to human illnesses (Williams et al, 2010). A weaker seasonal relationship between seasonal Salmonella contamination of all meat and poultry and human salmonellosis cases (Williams et al, 2014) has also been demonstrated.…”

Evidence for the benefits of food chain interventions on E. coli O157:H7/NM prevalence in retail ground beef and human disease incidence: A success story

“…3,4 E. coli O157:H7/NM is a pathogen with worldwide distribution, [5][6][7][8][9][10][11] with infections more commonly reported in northern latitudes 1,12 and in the summer. [13][14][15] E. coli O157:H7/NM may be carried by a wide range of animals, with cattle and other domestic ruminants recognized as important reservoirs. 16,17 Human infection can occur via consumption of contaminated food and beverages, recreational waters, and contact with humans or animals shedding the bacterium.…”

Standardized Escherichia coli O157:H7 Exposure Studies in Cattle Provide Evidence that Bovine Factors Do Not Drive Increased Summertime Colonization

“…Given the evidence linking human infection to the bovine reservoir, it is likely that the reduction of STEC O157 shedding in cattle during summertime might result in reduced carcass contamination rates at the abattoir and, ultimately, reduced human disease burden (29,30).…”