A study of risk factors for Campylobacter infection in late spring.

A case-control study was carried out to investigate possible reasons for the large increase in the number of cases of infection caused by Campylobacter species reported in the Regional Epidemiology Section of Manchester Public Health Laboratory in late spring each year. The hypothesis tested was that a risk factor peculiar to campylobacter infection is responsible for this phenomenon. Interviews about a wide variety of risk factors were conducted with 29 patients suffering from campylobacter enteritis and 41 out of a control group of 42 with acute diarrhoeal illness from other causes. The only statistically significant association with campylobacter infection was having had milk bottle tops pecked by birds, while previously recognised associated factors such as outdoor activities, pet ownership and consumption of chicken showed no significant association. Interviewees identified the birds responsible as magpies.