Duration of immunity of a quadrivalent vaccine against respiratory diseases caused by BHV-1, PI3V, BVDV, and BRSV in experimentally infected calves.
Several laboratory studies assessed the duration of immunity of a quadrivalent vaccine (Rispoval 4, Pfizer Animal Health) against bovine respiratory diseases (BRD) caused by bovine herpes-virus type-1 (BHV-1), parainfluenza type-3 virus (PI3V), bovine viral-diarrhoea virus type 1 (BVDV), or bovine respiratory syncytial virus (BRSV). Calves between 7 weeks and 6 months of age were allocated to treatment and then were injected with two doses of either the vaccine or the placebo 3 weeks apart. Six to 12 months after the second injection, animals were challenged with BHV-1 (n=16), PI3V (n=31), BVDV (n=16), or BRSV (n=20) and the course of viral infection was monitored by serological, haematological (in the BVDV study only), clinical, and virological means for > or =2 weeks. Infection induced mild clinical signs of respiratory disease and elevated rectal temperature in both vaccinated and control animals and was followed by a dramatic rise in neutralising antibodies in all treatment groups. Titres reached higher levels in vaccinated calves than in control calves after challenge with BHV-1, BVDV, or BRSV. On day 3 after PI3V challenge, virus shedding was reduced from 3.64 log10TCID50 in control animals to 2.59 log10TCID50 in vaccinated animals. On days 6 and 8 after BRSV challenge, there were fewer vaccinated animals (n=2/10 and 0/10, respectively) shedding the virus than control animals (n=8/10 and 3/10, respectively). Moreover, after challenge, the mean duration of virus shedding was reduced from 3.8 days in control animals to 1 day in vaccinated animals in the BVDV study and from 3.4 days in control animals to 1.2 days in vaccinated animals in the BRSV study. The duration of immunity of >or =6 months for PI3V, BHV-1 and BVDV, and 12 months for BRSV, after vaccination with Rispoval 4, was associated mainly with enhanced post-challenge antibody response to all four viruses and reduction of the amount or duration of virus shedding or both.
Peters
A R
AR
Veterinary Medicine Research and Development, Biologicals, Pfizer Animal Health, Sandwich CT13 9NJ, UK.
Thevasagayam
S J
SJ
Wiseman
A
A
Salt
J S
JS
D000818:Animals; D001912:Bovine Virus Diarrhea-Mucosal Disease / Q000517:prevention & control; D002417:Cattle; D002418:Cattle Diseases / Q000517:prevention & control*; D001908:Diarrhea Viruses, Bovine Viral / Q000276:immunology; D005260:Female; D006566:Herpesviridae Infections / Q000517:prevention & control / Q000662:veterinary; D007242:Herpesvirus 1, Bovine / Q000276:immunology; D007267:Injections / Q000662:veterinary; D008297:Male; D029101:Parainfluenza Virus 3, Bovine / Q000276:immunology; D012766:Pasteurellosis, Pneumonic / Q000517:prevention & control; D018357:Respiratory Syncytial Virus Infections / Q000517:prevention & control / Q000662:veterinary; D018112:Respiratory Syncytial Virus, Bovine / Q000276:immunology; D012141:Respiratory Tract Infections / Q000517:prevention & control / Q000662:veterinary*; D016896:Treatment Outcome; D006113:United Kingdom; D014481:United States; D014765:Viral Vaccines / Q000008:administration & dosage*
D014765:Viral Vaccines