# Figures—2011 Preliminary Data

FoodNet uses a main-effects, log-linear Poisson regression (negative binomial) model to estimate changes in the incidence of infection. The model adjusts for the increase in the number of FoodNet sites since 1996 and for variation in the incidence of infections among sites. The average annual incidence for 1) 1996–1998 (1997–1998 for *Cryptosporidium*), the first years of surveillance, and 2) a more recent 3-year period (2006–2008) are used for comparisons. The model is used to calculate the estimated change in incidence (relative rate) between 2011 and the comparison periods, with 95% confidence intervals (CI). In the figures that report percent change, the percent change for the current year is calculated by comparison with the appropriate comparison period and graphed along with the 95% confidence interval. In the figures that report relative rate, the relative rate for each year is graphed. Trends in STEC non-O157 and *Cyclospora *infection were not evaluated because of sparse data.

FoodNet also uses the negative binomial model to measure overall trends in incidence. In this model, data for *Campylobacter*, *Listeria*, *Salmonella*, STEC O157, *Yersinia*, and* Vibrio*, the bacterial pathogens for which >50% of illnesses are estimated to be transmitted by food, are combined, weighting them by incidence of infection for each pathogen.

## Figure 1. Percent change in incidence^{*} of laboratory-confirmed bacterial and parasitic infections in 2011^{†} compared with average annual incidence during 1996–1998, by pathogen, FoodNet

^{*}The estimates and confidence intervals presented indicate the relative change in the incidence of that pathogen compared with 1996–1998. The actual incidences of these infections
cannot be determined from the graph.

^{†}Data are preliminary

^{§}*No significant change* = 95% confidence interval is both above and below the no change line; *significant increase* = estimate and entire 95% confidence interval are above the no change
line; *significant decrease* = estimate and entire 95% confidence interval are below the no change line

¶Shiga toxin-producing *Escherichia coli*

## Figure 2. Relative rates of laboratory-confirmed infections with *Campylobacter*, STEC^{*} O157, *Listeria*, *Salmonella*, and *Vibrio* compared with 1996–1998 rates, by year, FoodNet 1996–2011^{†}

^{*}Shiga toxin-producing *Escherichia coli*

^{†}The position of each line indicates the relative change in the incidence of that pathogen compared with 1996–1998. The actual incidences of these infections cannot be determined from this graph.
Data for 2011 are preliminary.

## Figure 3. Relative rates of laboratory-confirmed infections with *Shigella*, *Yersinia*, and *Cryptosporidium* compared with 1996–1998 rates, by year, FoodNet 1996–2011^{*}

^{*}The position of each line indicates the relative change in the incidence of that pathogen compared with 1996–1998. The actual incidences of these infections cannot be
determined from this graph. Data for 2011 are preliminary.

## Figure 4. Percent change in incidence^{*} of laboratory-confirmed bacterial and parasitic infections in 2011^{†} compared with average annual incidence during 2006–2008, by pathogen, FoodNet

^{*}The estimates and confidence intervals presented indicate the relative change in the incidence of that pathogen compared with 2006–2008. The actual incidences of these infections cannot be determined from the graph.

^{†}Data are preliminary

^{§}*No significant change* = 95% confidence interval is both above and below the no change line; *significant increase* = estimate and entire 95% confidence interval are above the no change line; *significant decrease* = estimate and entire 95% confidence interval are below the no change line

¶Shiga toxin-producing *Escherichia coli*

## Figure 5. Percent change in incidence^{*} of laboratory-confirmed *Salmonella* infections with the top *Salmonella* serotypes in 2011^{†} compared with average annual incidence during 1996–1998, by serotype, FoodNet

^{*}The estimates and confidence intervals presented indicate the relative change in the incidence of that pathogen compared with 1996–1998. The actual incidences of these infections cannot be determined from the graph.

^{†}Data are preliminary. Percent change was not evaluated for serotypes I 4,[5],12:i:-, Javiana, and I 13,23:b:-.

^{§}*No significant change* = 95% confidence interval is both above and below the no change line; *significant increase* = estimate and entire 95% confidence interval are above the no change line; *significant decrease* = estimate and entire 95% confidence interval are below the no change line

## Figure 6. Relative rates of laboratory-confirmed *Salmonella* infections with the top *Salmonella* serotypes in 2011^{*} compared with 1996–1998 rates, by year, FoodNet 1996–2011^{†}

^{*}Data are preliminary. *Salmonella* serotypes included are: Enteritidis, Typhimurium, Newport, and Muenchen. Changes over time for serotypes I 4,[5],12:i:- , Javiana, and I 13,23:b:- were not evaluated.

^{†}The position of each line indicates the relative change in the incidence of that pathogen compared with 1996–1998. The actual incidences of these infections cannot be determined from this graph.

## Figure 7. Relative rates of laboratory-confirmed *Salmonella* infections with the top *Salmonella* serotypes in 2011^{*} compared with 1996–1998 rates, by year, FoodNet 1996–2011^{†}

^{*}Data are preliminary. *Salmonella* serotypes included are: Heidelberg, Montevideo, and Infantis. Changes over time for serotypes I 4,[5],12:i:-, Javiana, and I 13,23:b:- were not evaluated.

^{†}The position of each line indicates the relative change in the incidence of that pathogen compared with 1996–1998. The actual incidences of these infections cannot be determined from this graph.

## Figure 8. Percent change in incidence^{*} of laboratory-confirmed *Salmonella* infections with the top *Salmonella* serotypes in 2011^{†} compared with average annual incidence during 2006–2008, by serotype, FoodNet

^{*}The estimates and confidence intervals presented indicate the relative change in the incidence of that pathogen compared with 2006–2008. The actual incidences of these infections cannot be determined from the graph.

^{†}Data are preliminary

^{§}*No significant change* = 95% confidence interval is both above and below the no change line; *significant increase* = estimate and entire 95% confidence interval are above the no change line; *significant decrease* = estimate and entire 95% confidence interval are below the no change line

## Figure 9. Relative rates of laboratory-confirmed infections with *Campylobacter*, STEC^{*} O157, *Listeria*, *Salmonella*, *Vibrio*, and *Yersinia*, and overall measure of change, compared with 1996–1998 rates, by year, FoodNet 1996–2011^{†}

^{*}Shiga toxin-producing *Escherichia coli*

^{†}The position of each line indicates the relative change in the incidence of that pathogen compared with 1996–1998. The actual incidences of these infections cannot be determined from this graph. Data for 2011 are preliminary.

^{§}The measure of overall trends in incidence combines data for *Campylobacter*, *Listeria*, *Salmonella*, STEC O157, *Yersinia*, and *Vibrio*, the six key bacterial pathogens for which >50% of illnesses are estimated to be transmitted by food. The model weights by incidence of infection for each pathogen.

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