THE PORCINE REPRODUCTIVE AND RESPIRATORY SYNDROME - ISOLATION OF THE VIRUS AND EPIDEMIOLOGIC RESEARCH IN BELGIUM

The isolation of the porcine reproductive and respiratory syndrome (PRRS) virus in Belgium is reported. An epidemiological survey was carried out to find out to which extent the virus had spread in the Belgian pig population and whether the virus persisted on breeding farms. On 35 of the 39 sampled farms, sows with PRRS antibodies were present. It was concluded that the PRRS virus was enzootic in Belgium. It was investigated whether the PRRS virus is able to replicate in the uterus cavity after inoculation via the vagina. Three gilts in heat were inoculated in the uterus via the vagina and slaughtered 2, 4 and 6 days after the inoculation. Virus isolation was carried out on endometrium samples. Virus replication was also investigated in uterine macrophages isolated from the uterus of a PRRS-seronegative sow and inoculated in vitro. The results of this experiment indicate that the endometrium and the uterine macrophages cannot be considered as target organs for the PRRS virus.