Bird attack on milk bottles: possible mode of transmission of Campylobacter jejuni to man

A case-control study was carried out to test the hypothesis that the rise in the rate of Campylobacter jejuni infection in the Brigend area of South Wales during May was due to the consumption or handling of milk from bottles that had been attacked by birds. 32 of 36 cases meeting the case definition were interviewed, along with 2 controls per case, matched for age, sex, and area of residence. There were strong associations between campylobacter infection and doorstep delivery of milk bottles, a history of milk bottle attack by birds, milk bottle attack by birds during the week before illness, and consumption of milk from attacked bottles during the week before illness. There was a very strong dose-response relation between frequency of bird attack and illness. Controls with a history of milk bottle attack by birds were more likely than cases to have taken preventive measures against bird attack and consumption of contaminated milk. Although few people witnessed the attacks, the likely culprits are magpies (Pica pica) and jackdaws (Corvus monedula).