Effects of two commercial European modified-live vaccines against porcine reproductive and respiratory syndrome viruses in pregnant gilts.
The purpose of this study was to assess the effects of two currently available commercial European-type modified-live virus (MLV) vaccines against porcine reproductive and respiratory syndrome in a reproductive pig model. Sixteen 90-day pregnant gilts were divided into four groups and allocated to one of the following intranasal treatments: group A gilts served as negative controls; group B gilts were exposed to a virulent European field strain; group C gilts were exposed to vaccine strain VP046 Bis and group D gilts to vaccine strain All-183. The results indicated that MLV strains can replicate in breeding animals and have the ability to cross the placenta. In particular, viraemia was detected in all gilts in group C and 2/4 gilts in group D, at least at one time point. In addition, transplacental infection was demonstrated in 3/4 gilts in group C and 2/4 gilts in group D. However, congenital and early postnatal infection did not have a marked detrimental effect on piglet performance when compared to negative controls, and no statistically significant differences were observed in most cases. Conversely, the reproductive performance of gilts in group B was significantly worse than that of the other groups. Specifically, the number of born-alive piglets, the survival rate of piglets during lactation and the mean weight of weaned pigs were significantly lower. It was concluded that the two commercial European-type MLV vaccines tested had no marked detrimental effects in pregnant gilts, although the MLV strains can cross the placenta leading to the birth of congenitally infected piglets.
Scortti
Mariela
M
Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad Complutense de Madrid, Avda Puerta de Hierro s/n, Madrid, Spain.
Prieto
Cinta
C
Martínez-Lobo
Francisco J
FJ
Simarro
Isabel
I
Castro
José M
JM
D000818:Animals; D000831:Animals, Newborn; D000914:Antibodies, Viral / Q000097:blood; D005260:Female; D019318:Porcine Reproductive and Respiratory Syndrome / Q000151:congenital / Q000276:immunology* / Q000517:prevention & control / Q000628:therapy*; D019316:Porcine respiratory and reproductive syndrome virus / Q000276:immunology*; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000276:immunology / Q000628:therapy*; D011256:Pregnancy Outcome / Q000662:veterinary; D013552:Swine; D014613:Vaccines, Attenuated / Q000276:immunology / Q000627:therapeutic use; D014765:Viral Vaccines / Q000276:immunology / Q000627:therapeutic use*; D014766:Viremia / Q000276:immunology / Q000662:veterinary
D000914:Antibodies, Viral; D014613:Vaccines, Attenuated; D014765:Viral Vaccines