PCV2 Infection in Vaccinated Conventional Gilts
Inseminated with PCV2b-Spiked Semen
Carlo Bianco1,*,
Giuseppe Sarli1, Serena Panarese1, Maria Laura
Bacci1, Giovanna Galeati1, Michele Dottori2,
Paolo Bonilauri2, Davide Lelli3, Giorgio
Leotti4, Thaïs Vila5, François Joisel5
and Fabio Ostanello1
1Department of Veterinary Medical Sciences,
University of Bologna, Via Tolara di Sopra 50, 40064, Ozzano Emilia,
Bologna, Italy; 2Istituto Zooprofilattico Sperimentale
della Lombardia e dell’Emilia-Romagna (IZSLER) – Section of Reggio
Emilia, Via Pitagora 2, 42100, Reggio Emilia, Italy; 3Istituto
Zooprofilattico Sperimentale della Lombardia e dell’Emilia-Romagna
(IZSLER), Via A. Bianchi 9, 25124, Brescia, Italy; 4Merial
Italia Spa, Strada 6, Palazzo E/5, 20090 Milanofiori, Assago, Milan,
Italy; 5Merial SAS, 29 avenue Tony Garnier, 69007, Lyon,
France *Corresponding author: carlo.bianco3@unibo.it
Abstract
The present trial
investigated the effect of PCV2 vaccination on viremia, virus shedding and viral
load in maternal tissues and foetuses of conventional gilts inseminated with
PCV2b-spiked semen.Twelve gilts were randomly divided into two groups
of six animals each (vaccinated infected, VI;
non-vaccinated infected, NVI).
Estrus synchronization was followed by artificial insemination (AI) with a
single PCV2 negative semen dose supplemented with 0.2 mL of a PCV2b suspension
containing 104.4 TCID50/50 μL (total viral dose: 105 TCID50).Vaginal, nasal and faecal swabs, and blood samples were collected weekly
from two days before artificial inseminationtill the end of the experimental period (55 days post AI; DPAI) and
tested by real-time PCR (qPCR) for PCV2; sera were tested for anti-PCV2
antibodies. During necropsy foetal and maternal tissues were collected for qPCR
and histopathology.In each of the VI and NVI groups three out of the
six gilts were pregnant at 29 DPAI. The VI group showed a significantly lower
proportion of PCR-positive swabs: 24.6% VI
vs 71.3% NVI. PCV2 clearance was demonstrated by qPCR in
lymphoid tissue during the trial in the VI group. Only one foetus was PCV2-positive (in the NVI group) and three amniotic
fluids of the NVI group. PCV2 was found in a significantly lower proportion of
the placenta of foetuses in the VI group (39%) than the NVI group (77%). The
PCV2 vaccine seems to play an active role in reducing virus shedding, tissue
viral load and foeto-placental infection.
Key words:
Infection,
Porcine circovirus type 2,
Semen,
Swine, Vaccine