**4. Prevention**

Prevention of *Coxiella burnetii* shedding in cattle is critical to control the spread of the pathogen between animals and from animals to humans. A herd or a flock should be considered clinically infected with Q fever when abortion or stillbirths have occurred, positive PCR results confirming the presence of *Coxiella burnetii* on specimens from affected animals, positive results in the serology test. In cattle herds, the occurrence of a series of abortion: for herds less than 100 animals 2 abortion or more in the month or 3 abortions in the year; for herds more than 100 animals more than 4% of cows with abortions in the year, is the major warning sing to be taken into account (Sidi-Boumedine et al., 2010).

Proceedings in the environment of healthy animals include a serological test of animals fur, quarantine of imported animals, the prohibition on animal breeding farms from areas where infection occurred, the serological tests of crossing animals, the fight against ticks and rodents. If Q fever occurs, the following activities should be performed: the district veterinarian must notify diagnostic laboratory indicating a positive result, sporadic cases should be eliminated, the animals should be selected to serologically positive and negative in the case of numerous infections in the herd, the dynamics of antibodies should be studied in animals showing the presence of antibodies, disinfection of rooms should be performed, farrowing should be separated, placenta and the stillborn foetuses should be protected after each delivery, the direction of Q fever should be examined in newborn animals.

The newest study made in Denmark reported an increased risk of becoming infected with *Coxiella burnetii* for herds where farmers had bought cattle from other herds. Therefore, as a general rule, the purchase of animals should be avoided as much is possible, even if tests before introduction are implemented (EFSA Panel on Animal Health and Welfare (AHAW), 2010).

Prevention of *Coxiella burnetii* shedding in cattle or sheep and goat is critical to control the spread the pathogen. Q fever vaccination of animals is not widely used because it is protective and safe only for animals that are uninfected at the time of vaccination. Moreover, extensive evaluation of the protective effect of such a vaccination on animal and human health compared to the cost of such prophylactic measures is lacking. There are two types of vaccines. The first one contains formalin-killed whole-cell vaccine preparations (WCV) and the second one - chloroform methanol-extracted bacterial residue (CMR). A WCV from the Henzerling strain (Q vax, CSL Limited, Parkville, Victoria, Australian) has been commercially available and used from human vaccination in Australia since 1989 (Arricau-Bouvery & Rodolaski, 2005). Among 942 no immune abattoir workers in Australia who were vaccinated, no Q fever case was diagnosed during 18 month whereas 34 cases were recorded among 1,349 unvaccinated controls (Marmion et al., 1984). This vaccination is very useful in the protection of exposed populations such as veterinarians or breeders of animals. A soluble vaccine containing trichloroacetic acid-extracted antigen from phase I *Coxiella burnetii* nine mile strain was successfully used in Czechoslovakia. In animal, the vaccines composed of inactivated whole phase I bacteria are the most effective. Bacterial shedding in milk and placentas was strongly reduced in infected animals vaccinated with phase I vaccines. Available vaccines are prepared with a single strain and therefore, they are monovalent. The recent works have shown that the vaccines reduce the shedding of *Coxiella burnetii.* These results are very important because of limiting the clinical disease in animals and human (Arricau-Bouvery & Rodolaski, 2005).
