Q fever and prevalence of Coxiella burnetii in milk

Abstract

Background Q fever is a zoonosis caused by Coxiella burnetii. In humans, although it has been predominantly considered an occupational hazard, in the last decades, Q fever outbreaks have also been reported in various countries, indicating its importance as an emerging public health threat. Domestic ruminants are considered as the most important sources of human infection. In fact, both symptomatic and asymptomatic infected ruminants shed the bacterium into the environment with birth products, but also in urine, faeces, vaginal mucus and milk. Q fever in humans is mainly asymptomatic, but it also may manifest itself as an acute or chronic disease with long-term sequelae. Inhalation of infectious aerosols usually causes the disease in humans, but the presence of C. burnetii in raw milk raises concern over the role of milk as a source of infection. Scope and approach In this review data on Q fever in humans are summarized and the possible transmission of C. burnetii to humans by consumption of unpasteurized milk is discussed. In addition, an overview of the published data on the prevalence studies of C. burnetii in raw milk in various countries is provided. Key findings and conclusions Recent surveys conducted in many countries have revealed that the prevalence of C. burnetii in raw milk can vary over a wide range from 0% to as high as 95%. Based on recent survey data, the risk of C. burnetii infection by consuming unpasteurized milk and raw milk products cannot be considered negligible. © 2017 Elsevier Ltd