Temporal patterns in principal Salmonella serotypes in the USA; 1996-2014

Area of Science:

• Foodborne illness surveillance
• Infectious disease epidemiology
• Public health microbiology

Background:

• Analyzing temporal patterns in foodborne illness is crucial for effective food safety measures.
• The incidence of Salmonella infections in the USA has not declined since 1996.
• Specific Salmonella serotypes display significant annual trends and complex seasonal patterns.

Purpose of the Study:

• To estimate temporal patterns in the reported incidence of illness for the top three Salmonella serotypes.
• To analyze annual and seasonal trends for Salmonella serotypes Typhimurium, Enteritidis, and Newport.
• To provide confidence bands for estimated incidence curves.

Main Methods:

• Utilized data from original Foodborne Diseases Active Surveillance Network (FoodNet) sites (1996-2014).
• Employed penalized cubic B-spline regression to model temporal patterns.
• Estimated annual and monthly incidence curves with 95% confidence bands for each serotype.

Main Results:

• Salmonella serotype Typhimurium showed a significant declining annual trend and seasonality with peaks in late summer and early winter.
• Salmonella serotype Enteritidis exhibited a significant annual trend (increasing incidence over time) and seasonality, peaking in late summer.
• Salmonella serotype Newport displayed significant seasonality with a late summer peak but no significant annual trend.

Conclusions:

• Temporal analysis reveals distinct trends and seasonality for major Salmonella serotypes, despite stable overall incidence.
• Understanding serotype-specific patterns is vital for targeted food safety interventions and public health strategies.
• Seasonal peaks, particularly in late summer, highlight critical periods for heightened surveillance and prevention efforts.