Figure 3

Seasonality of the national and divisional salmonellosis-associated hospitalization rates. The time series of weekly rate (cases per 1,000,000 elderly) against year for each of the nine Census divisions was superimposed with predicted values obtained from the annual harmonic regression. The time label of the x-axis was transformed into year for easier interpretation of the annual pattern. The vertical reference line indicates the start of year 1997, the introduction of the Hazard Analysis and Critical Control Points Systems regulation on testing Salmonella in major chicken broilers.