Specific risk factors for contracting Q fever: lessons from the outbreak Jena.

A Q fever outbreak with 331 reported cases in seven weeks occurred in a densely populated residential district in Jena (Germany) in 2005. Prompt identification of a stable infection source follow by an intense information policy, well defined and stable meteorological conditions and a large number of reported cases within one small community all allowed us to study promoting and protecting factors of Q fever. We conducted a cross-sectional study and investigated a part of the affected area for 100% sampling (in-home interviews).