Risk of a Brucella Transmission by Porcine Embryos: an in Vitro Study

Introduction The cryoconservation of pig embryos with intact zona pellucida would be a major advantage to control and then insure minimal risk of disease transmission during embryo transfer of genetic material. Moreover, international rules on embryo transport outside of the country origin require that only embryos with an intact zona pellucida may be exported [9]. A vitrification technique is currently being studied in several species to resolve the problems of cryopreservation. Recently, a new technique has been developed to increase the cooling and warming rates of vitrification named Open Pulled Straw (OPS) technology [11]. The faster cooling rate seems to be one of the key solutions to protect porcine embryos from chilling injuries and to obtain piglet births after vitrification of unhatched blastocysts [2,3]. The OPS method allows the conservation of genetic resources and opens possibilities for porcine embryo transfer industry. In particular, exchange of genetic material between countries may then be simplified. However, pathogens could be cotransferred with embryos. Transmission by embryo transfer of viruses to swine has been studied [10], and transmission of bacteria has been few investigated [7]. This study reports the evaluation of risks of transferring Brucella species via porcine embryos. The choice of Brucella genus relies on the re-emergence of brucellosis in pigs due to Brucella suis biovar 2 responsible for abortion, orchitis and sterility in swine, since 1993, in France and on the enzootic presence of this biovar in other European countries [5].