Effect of a porcine circovirus type 2 infection on embryos during early pregnancy

Abstract

The aim of the present study was to assess the effects of porcine circovirus type 2 (PCV2) on porcine embryos and their receptor sows during the first 21 days of pregnancy. Hatched blastocysts exposed to 10 5.0 TCID 50 PCV2 per ml (strain 1121, fifth passage PK15) and negative control embryos were transferred to PCV2-immune receptor sows at the 7th day of the cycle. Two weeks after transfer (D21), the receptor sows were euthanized and embryos were recovered. They were assessed macroscopically for viability and examined for viral antigen-positive cells by immunoperoxidase staining. The embryonic survival rate of the PCV2-exposed embryos (6.4%, 7 viable embryos out of 110 transferred) was significantly lower than the survival rate of the negative control embryos (65.4%, 34 viable embryos out of 52 transferred). All of the non-viable PCV2-exposed embryos (n = 9) displayed immunohistochemical positive signals for PCV2-antigen in degenerated tissues. In the PCV2-exposed embryos that were categorized as viable at D21, small clusters (n = 4) or no PCV2-positive cells (n = 3) were detected. The pregnancy results of the receptor sows that received PCV2-exposed embryos (1/5) were considerably different from the negative control receptors (2/2), with 3 out of 5 sows displaying a regular return to oestrus.In conclusion, it can be stated that PCV2 can replicate in embryos and might lead to embryonic death. In a small proportion of embryos, PCV2 exposure does not have a detrimental effect on embryo development before D21. #

Diseases in swine transmitted by artificial insemination: An overview

“…That this virus can be intermittently excreted by infected boars, semen may be an important means of transmission. The virus is also able to replicate in zona pellucida-free embryos, leading to embryonic death [23,24].…”

14_Artificial Insemination and Its Role in Transmission of Swine Viruses

“…The virus is also able to replicate in the zona pellucida-free embryos, leading to embryonic death (Mateusen et al, 2004(Mateusen et al, , 2007. Delayed farrowing (>118 days of gestation) (LadekjaerMikkelsen et al, 2001) or pseudopregnancy (Josephson & Charbonneau, 2001) is less frequently observed with PCV2-associated reproductive failure.…”

Dynamics of porcine circovirus type 2 infection and neutralizing antibodies in subclinically infected gilts, and the effect on their litters

“…In mature breeding animals, PCV2-associated reproductive failure can manifest as abortion, but it is more frequently associated with increased rates of mummified, macerated, stillborn and weak-born piglets (West et al ., 1999;O'Connor et al ., 2001). The experimental intrauterine infection with PCV2 resulted in virus replication in the fetuses (Sánchez et al ., 2001;Madson et al ., 2009a;Saha et al ., 2010), reproductive disease associated with fetal pathology (Johnson et al ., 2002) and early embryonic death during intrauterine PCV2 infection (Mateusen et al ., 2007). Other case reports of reproductive failure implicated PCV2 either as the sole agent or in conjunction with other reproductive disease agents (Brunborg et al ., 2007;Castro et al ., 2012).…”