Sporadic illness drives rising US campylobacteriosis incidence over two decades

Announcing a new article publication for Zoonoses journal. Campylobacteriosis is monitored by several U.S. surveillance systems, including the Foodborne Diseases Active Surveillance Network (FoodNet), the National Notifiable Diseases Surveillance System (NNDSS), and the National Outbreak Reporting System (NORS). FoodNet conducts active surveillance across 10 sites, while NNDSS conducts national passive surveillance, and NORS captures data on outbreaks. Understanding the similarities and differences among these systems is essential for informing prevention and reducing disease burden.

Data reported to each system during 2004-2023 were analyzed. Trends were modeled using spline regression, and incidence rate ratios were used to characterize changes in epidemiology.
The clinical and patient characteristics of illnesses reported to FoodNet and NNDSS were similar. Both systems showed a sustained increase in incidence starting in 2010, with increasing concordance after 2015.

The results support the use of NNDSS for monitoring national trends. Adoption of culture-independent diagnostic tests (CIDT) likely drove some of the increase in the reported campylobacteriosis incidence, but cannot fully explain it. Moreover, because outbreak frequency remained stable during 2004-2023 but outbreak size decreased, the increases in campylobacteriosis incidence observed were probably driven by sporadic rather than outbreak-associated illness. This underscores the need for enhanced attribution methods and strengthened prevention strategies to better understand and address non-CIDT factors contributing to this increase.