Coxiella burnetii: A review focusing on infections in German sheep and goat flocks

Q fever is a worldwide zoonosis caused by Coxiella (C) burnetii. This bacterium is shed in huge amounts with birth products from infected small ruminants. Shedding also occurs via milk, faeces and urine. The main route of infection for humans and animals is via inhalation of contaminated aerosols. Apart from wind, many other meteorological conditions influence pathogen dissemination. Also, Dermacentor spp. and Ixodes ricinus ticks could play a role in transmission. Infections in goats can lead to abortion during the last trimester of pregnancy. In comparison to goats, C. burnetii seems to cause less abortion in sheep. In humans, 4096 of infected persons show flu-like symptoms such as fever and headaches. Up to 5% of all infected people can develop chronic Q fever, which often manifests as endocarditis. Since 2000, several human Q fever epidemics occurred in Germany with up to 331 reported human infections. The source of infection was mostly associated with parturition of sheep. As the number of goats has increased in Germany over the last couple of years, Q fever cases connected to this species will probably increase in the future. For the detection of C. burnetii in animals, ELISA and/or PCR are routinely used. With Multiple Loci Variable Number of Tandem Repeats Analysis (MLVANNTR) it is possible to genotype isolates. MLVA-Cluster A was detected in samples from small ruminants, Cluster C is associated with cattle. Treatment with oxytetracycline is ineffective for the control of Q fever in animals, whereas the use of an inactivated Phase I whole cell vaccine reduces shedding and therefore the risk of transmission. Many disinfectants are ineffective against C. burnetii because of its high tenacity.