[Outbreak of Campylobacter fetus infection after consumption of unpasteurized sheep's milk cheeses: how to trace the source?]

Campylobacter fetus is a species of gram-negative bacteria whose primary reservoir is the gastrointestinal tracts of cattle and sheep. Human infections are rare, though often invasive and sometimes fatal. In this paper, we studied an outbreak of six patients with a C. fetus infection and outlined their disease histories. In each case we were able to identify factors that led to a reduced resistance, including pre-existing illnesses and old age. Because of the unusually high number of patients that presented in a time period of only five months, the Community Health Services were commissioned to identify the source of infection. Using whole genome sequencing, we showed that 5 out of 6 patients belonged to the same cluster. This One Health approach resulted in the conclusion that the infection originated from unpasteurized sheep's milk processed into unripened cheese. Finally, various measures were put into place to prevent any further outbreaks.