Experimental infection of 35, 50 and 60 day old pig foetuses with porcine parvovirus

Foetuses of six seronegative gilts, two of which each respectively 35, 50 and 60 days pregnant, were inoculated intrauterinely with porcine parvovirus (PPV) and examined 7 and 11 days after inoculation. HI antibody was not detected in any of the foetuses although all but one gilt developed low levels of antibody. All but one of the foetuses inoculated with PPV died in utero prior to examination at 11 days after inoculation. Infection also spread to non-inoculated litter mates. Histological changes were mild in the gilts but there was widespread tissue necrosis in infected foetuses, and intranuclear inclusion bodies were observed in cells of the liver, lung, kidney and cerebellum. The increased survival of foetuses infected at later stages of gestation appeared to be related to increased numbers of mononuclear cells then present in many tissues.