Vaccination against porcine parvovirus protects against disease, but does not prevent infection and virus shedding after challenge infection with a heterologous virus strain

Abstract

The demonstration of field isolates of porcine parvovirus (PPV) that differ genetically and antigenically from vaccine strains of PPV raises the question of whether the broadly used inactivated vaccines can still protect sows against the novel viruses. Ten specific-pathogen-free primiparous sows were assigned to three groups and were vaccinated with one of two vaccines based on the old vaccine strains, or served as non-vaccinated controls. After insemination, all sows were challenged with the prototype genotype 2 virus, PPV-27a, on gestation day 41; fetuses were delivered on gestation day 90 and examined for virus infection. The fetuses of the vaccinated sows were protected against disease, but both the vaccinated and the non-vaccinated sows showed a marked increase in antibody titres after challenge infection, indicating replication of the challenge virus. All sows (vaccinated and non-vaccinated) shed the challenge virus for at least 10 days after infection, with no difference in the pattern or duration of virus shedding.

Increasing diversity of swine parvoviruses and their epidemiology in African pigs

“…The virus is highly ubiquitous and has been found in swine herds of different categories including domestic and wild pigs, breading age females and boars, young piglets and fattening pigs (Dea et al, 1985;Duhamel et al, 1991;Lager and Mengeling, 1994;Drolet et al, 2002;Cadar et al, 2012;Truyen and Streck, 2012). It has also been discovered among pigs of different health statuses including vaccinated and non-vaccinated pigs, healthy and sick pigs (Jóźwik et al, 2009).…”

“…However, it has been proven experimentally that both homologous and heterologous inactivated PPV1 vaccines can not prevent viral infection and shedding, thereby making total immunization and subsequent eradication of the virus impossible. This, therefore, necessitates the need for a consistent follow-up vaccinations of all breeders appropriately (Jóźwik et al, 2009;Foerster et al, 2016). This limitation, coupled with seeming emergence of new strains of PPV1 that show lower homology with the vaccine strains, therefore necessitates futher development of more efficient vaccines (Jóźwik et al, 2009;Ren et al, 2013;Streck et al, 2015a).…”

Antiviral effect of lithium chloride on infection of cells by porcine parvovirus

“…Additionally, even with vaccination, PPV is widespread in swine. Although vaccination can prevent the clinical symptoms of the PPV disease, it cannot eliminate the impairment caused by PPV disease [10,11]. Therefore, alternative strategies, such as drug therapies to control the PPV, should receive increased attention.…”

Classic Nuclear Localization Signals and a Novel Nuclear Localization Motif Are Required for Nuclear Transport of Porcine Parvovirus Capsid Proteins

“…Infection can then result in death of the fetus, depending on the strain and time of gestation at which infection occurred (4)(5)(6). Despite the fact that vaccines are widely used and efficiently prevent reproductive problems, the virus can still replicate and be shed from infected sows (7). This results in the constant presence of PPV in herds, enabling the occurrence of mutated field strains.…”