Protection of puppies against canine herpesvirus by vaccination of the dams

Abstract

Six bitches free of canine herpesvirus 1 (CHV-1) were vaccinated against the virus; a first injection was given 10 days after the presumed date of mating and a second six weeks later. Six similar bitches were left unvaccinated as controls, and all the pups were challenged oronasally with a virulent strain of CHV-1 at three days of age. All the vaccinated bitches seroconverted and had high antibody titres when the puppies were challenged, but the control bitches remained seronegative. In the control group, 62 per cent (18 of 29) of the pups died of CHV-1-induced disease; most of them showed typical clinical signs and macroscopic lesions, and CHV-1 infection was confirmed by the isolation of the virus or by PCR. None of the puppies in the vaccinated group died of CHV-1 infection. The efficacy of the vaccine was confirmed in CHV-1-positive breeding units. The rate of pregnancy tended to be higher in vaccinated bitches and the mortality of pups before weaning was significantly reduced in the litters born to vaccinated bitches.

Pathology Isolation and Identification of Canine Herpesvirus (CHV-1) in Mexico

“…In the brain, we observed severe congestion, severe diffuse non-suppurative meningoencephalitis, perivascular lymphocytic infiltration, and the presence of intranuclear inclusion bodies in neurons. All of the results agreed with previously reported findings for this disease [12]- [14].…”

“…Then, viral replication occurs in the vascular endothelium, leading to necrotizing vasculitis and hemorrhages [14] [15].…”

“…The histopathological findings from natural or experimental infections in newborns puppies were characterized by scattered foci of necrosis with peripheral hemorrhages in the kidneys, lungs, spleen, small intestine and brain [12]- [14]. These foci of necrosis and hemorrhages were found in the examined puppies, with hemorrhages being the most apparent, while necrosis was less prominent; however, no necrotic foci were found in the brain.…”

L'herpèsvirose canine

“…La fertilité a ainsi été suivie avant et après vaccination dans sept éle-vages contaminés par le CHV-1 et souffrant de troubles de la reproduction (Poulet et al 2001). Dans chacun des élevages, des chiennes ont été vaccinées et d'autres non, selon un choix aléatoire.…”

“…Ainsi, dans un effectif de chiots Yorkshire, ceux nés de mères vaccinées (n=22) ont montré un poids moyen à la naissance significativement plus élevé (p=0,02) de 124 ± 53 grammes contre 85 ± 36 grammes pour ceux nés de mères non vaccinées (n=14) (Poulet et al 2001). Il est vraisemblable que, chez les chiennes gestantes vaccinées, le placenta, protégé de l'infection virale, se développe et permet la croissance des foetus jusqu'à un poids normal à la naissance.…”