https://www.ncbi.nlm.nih.gov/books/NBK537033/ - "According to the United States Centers for Disease Control, there are about 1.3 million cases of Campylobacter infection each year in the United States alone." ("Update: December 29, 2019")

63 million population in the UK. 330 million in the US. Ratio = 1/5.2 .

57K cases in the UK, 1.3 million in the US. Ratio = 1/23 .

=> about 4x more likely in the US.