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The aim of this study was to determine if the placental transmission of PCV-2 followed by virus transmission to piglets, depends on the dam’s infection time before or during the gestation.
Four sows served as negative controls. Ten sows, free of PCVs, were infected nasally at days -65, -35, 0, +35, +62 or +91 relating to the beginning of gestation. The sows were killed few days before farrowing for hysterectomia. All fetuses were identified and euthanized. Viral genomic loads in serum and organs, and PCV-2 specific antibodies levels were assessed. The trial was performed according EU regulations on animal experimentation.
All infected sows became viremic and seroconverted. All the piglets born to infected sows were seronegative. All the piglets from the sows inoculated at +35 days, before the time of fetus immuno-competency, were negative for the presence of PCV-2. Few piglets from sows infected at days -65, -35, +62 and +91 had low genomic loads in organs. Moderate to high viral genomic loads were detected in the organs of eight seronegative pigs born to sows infected at days -35, 0 and +62.
In conclusion, placental transmission of PCV-2 from a non-immune sow to fetuses is possible when the infection of the dam occurs before gestation or after 62 days of gestation.
B. Grasland, R. Cariolet, L. Bigault, C. Bernard, A.-C. Nignol-Hernandez, L. Gourves, A. Keranflec’h, A. Jestin, N. Rose. Transmission placentaire du circovirus porcin de type 2 (PCV-2). 46èmes Journées de la Recherche Porcine.