Q fever (coxiella burnetii): A blueprint for outbreaks

Abstract

About 80 years ago, Q fever research began due to human outbreaks of unknown origin, associated with domestic animals. Since then, some but not all characteristics of this “query” disease, caused by the intracellular bacterium Coxiella burnetii were revealed. In this chapter the bacteriology of the bacterium, clinical presentation, epidemiology and transmission of the disease in humans and animals are presented. Domestic small ruminants are the main source of human Q fever. Although Q fever is considered to be an occupational disease, outbreaks have a major public health impact and attract most attention. The Dutch Q fever outbreak, involving 4000 human cases over the years 2007–2010, is an example of how Q fever can re-emerge from an endemic state into an outbreak of unforeseen dimension. In this outbreak the epidemiological link between dairy goats and human cases was confirmed by genotyping for the first time. This was possible due to the previous development of genotyping assays that are applicable on clinical material. Although Q fever seems to be a blue print for outbreaks it is not known yet what factors are essential to cause outbreaks and how they interact. To prevent outbreaks, a better understanding of these factors and their interaction is necessary and research should therefore focus on this.