PROTECTION OF DOGS AGAINST CANINE-DISTEMPER BY VACCINATION WITH A CANARYPOX VIRUS RECOMBINANT EXPRESSING CANINE-DISTEMPER VIRUS FUSION AND HEMAGGLUTININ GLYCOPROTEINS

Objectives-To evaluate the safety and efficacy of a live canarypox vir us recombinant-canine distemper virus (CDV) combination Vaccine agains t virulent CDV challenge exposure, and to document lack of interferenc e among the other modified-live virus (MLV) components. Animals-33 spe cific-pathogen-free (SPF) Beagle pups (7 to 10 weeks old). Procedure-A canarypox virus recombinant-CDV combination vaccine was tested for sa fety and efficacy along with MLV components (canine adenovirus type 2, canine coronavirus, canine parainfluenza virus, and canine parvovirus ) in 26 SPF Beagle pups. The combination vaccine was rehydrated with e ither Leptospira canicola-L icterohaemorrhagiae combination bacterin ( vaccine 1) or sterile diluent (vaccine 2). An additional group of 7 se ronegative SPF pups received the control MLV components devoid of the combination vaccine (vaccine 3). Two vaccinations were administered 21 days apart, either IM or SC. The dose of the combination vaccine used to inoculate these pups was 40 times lower than the recommended comme rcial dose. At 21 days after the booster vaccination, all pups were ch allenge exposed with a virulent CDV strain, then were observed for 21 days to record morbidity and mortality. Results-Adverse local or gener alized reactions were not induced by vaccinations. All Vaccinates sero converted to CDV. Serum antibody titers to MLV components were not dif ferent, with or without inclusion of the combination vaccine. After ch allenge exposure, morbidity and mortality in vaccinates were 0% (0/26) ; in control dogs, values were 100% morbidity and 86% mortality (6/7). Brain impression smear slides made from all dogs that did not survive challenge exposure were CDV positive by use of a direct fluorescein i sothiocyanate method. Conclusions-The canarypox virus-CDV combination vaccine, administered SC or IM, is a safe product that elicits CDV ser oconversion, does not interfere with other Vaccine components, and pro tects vaccinated pups against virulent CDV challenge exposure.