Investigation of a Q fever outbreak in a rural area of The Netherlands.
A Q fever outbreak occurred in the southeast of The Netherlands in spring and summer 2007. Risk factors for the acquisition of a recent Coxiella burnetii infection were studied. In total, 696 inhabitants in the cluster area were invited to complete a questionnaire and provide a blood sample for serological testing of IgG and IgM phases I and II antibodies against C. burnetii, in order to recruit seronegative controls for a case-control study. Questionnaires were also sent to 35 previously identified clinical cases. Limited environmental sampling focused on two goat farms in the area. Living in the east of the cluster area, in which a positive goat farm, cattle and small ruminants were situated, smoking and contact with agricultural products were associated with a recent infection. Information leaflets were distributed on a large scale to ruminant farms, including hygiene measures to reduce the risk of spread between animals and to humans.