Experimental Inoculation of Porcine Circovirus 3 (PCV-3) in Pregnant Gilts Causes PCV-3-Associated Lesions in Newborn Piglets that Persist until Weaning

Figure 7

Proposed pathogenesis scheme of the intrauterine infection by PCV-3. The experimentally exposed (intranasally and intramuscularly) pregnant gilts to PCV-3 resulted in transplacental infection of a proportion of fetuses and delivery of PCV-3-infected piglets. These piglets featured PCV-3-associated disease histopathological lesions (as described by Saporiti et al. [6]) at farrowing and at weaning ages, as well as presence of PCV-3 in lymphoid tissues. Infection of cardiac and nervous tissue appeared to be gestational age-dependent, since only piglets coming from gilts inoculated at the second third of gestation (T1) developed myocarditis and encephalitis. From farrowing to weaning, a worsening of these inflammatory lesions was observed, which was accompanied by a decrease in body weight at weaning. Histopathological lesions were always more severe in piglets from gilts inoculated during the second third of gestation (T1), suggesting that the earlier the infection during gestation, the more severe lesions.