Comprehensive literature review of the sources of infection and transmission routes of Coxiella burnetii, with particular regard to the criteria of "evidence-based medicine".

The present review aims to compile the currently available literature since 1936 according the sources of infection of the Q fever pathogen (Coxiella (C.) burnetii) as well as the transmission from animal to man and also from human to human. In terms of quality and validity, the existing publications were reviewed systematically. For this purpose, firstly a structured literature search was carried out using various databases and search engines supplemented by a manual literature search. For critical appraisal, 1444 relevant publications were identified for the moment and evaluated. A total of 73 publications describing a transmission of C. burnetii from animals to man or a human-to-human transmission were discovered. The identified publications are 29 case series, two case reports, 21 cohort studies and 21 case-control studies. With regard to the sources of infection, 25 publications describing the transmission of C. burnetii from sheep to humans could be identified.