A surveillance project in Denmark using whole-genome sequencing (WGS), published by the journal Eurosurveillance, has found that many Campylobacter infections are not sporadic, and helped uncover a large outbreak. 

The study revealed that about half of human infections belong to genetic clusters, almost one-third of clinical isolates match a chicken source, and most large clusters can be linked to poultry by WGS.

Scientists hope the knowledge raised will lead to a decrease in the Danish chicken-associated cases of campylobacteriosis in coming years.

In 2019, Denmark had 5,389 cases and 33 percent of conventional chicken meat samples were positive for Campylobacter at slaughter. One-third of infections are estimated to be travel-related. 

Typing-based surveillance of Campylobacter infections in 2019 enabled detection of large clusters and matched them to retail chicken isolates to react to outbreak. According to the study, surveillance was also able to detect prolonged or reappearing outbreaks to help earlier interventions.