title: Oral vaccination and protection of red foxes (Vulpes vulpes) against rabies using ONRAB, an adenovirus-rabies recombinant vaccine.
abstract: Twenty-seven red foxes (Vulpes vulpes) were each offered a bait containing ONRAB, a recombinant oral rabies vaccine that uses a human adenovirus vector to express the immunogenic rabies virus glycoprotein; 10 controls received no vaccine baits. Serum samples collected from all foxes before treatment, and each week post-treatment for 16 weeks, were tested for the presence of rabies virus neutralizing antibody (RVNA). In the bait group, a fox was considered a responder to vaccination if serum samples from 3 or more consecutive weeks had RVNA ≥0.5 IU/ml. Using this criterion, 79% of adult foxes (11/14) and 46% of juveniles (6/13) responded to vaccination with ONRAB. Serum RVNA of adults first tested positive (≥0.5 IU/ml) between weeks 1 and 3, about 4 weeks earlier than in juveniles. Adults also responded with higher levels of RVNA and these levels were maintained longer. Serum samples from juveniles tested positive for 1-4 consecutive weeks; in adults the range was 2-15 weeks, with almost half of adults maintaining titres above 0.5 IU/ml for 9 or more consecutive weeks. Based on the kinetics of the antibody response to ONRAB, the best time to sample sera of wild adult foxes for evidence of vaccination is 7-11 weeks following bait distribution. Thirty-four foxes (25 ONRAB, 9 controls) were challenged with vulpine street virus 547 days post-vaccination. All controls developed rabies whereas eight of 13 adult vaccinates (62%) and four of 12 juvenile vaccinates (33%) survived. All foxes classed as non-responders to vaccination developed rabies. Of foxes considered responders to vaccination, 80% of adults (8/10) and 67% of juveniles (4/6) survived challenge. The duration of immunity conferred to foxes would appear adequate for bi-annual and annual bait distribution schedules as vaccinates were challenged 1.5 years post-vaccination.
authors.affiliation: Wildlife Research and Monitoring Section, Ontario Ministry of Natural Resources, Trent University, DNA Building, 2140 East Bank Drive, Peterborough, Ontario K9J 7B8, Canada. Electronic address: lucy.brown@ontario.ca.
authors.forename: L J
authors.initials: LJ
authors.lastname: Brown
authors.affiliation: Wildlife Research and Monitoring Section, Ontario Ministry of Natural Resources, Trent University, DNA Building, 2140 East Bank Drive, Peterborough, Ontario K9J 7B8, Canada.
authors.forename: R C
authors.initials: RC
authors.lastname: Rosatte
authors.affiliation: Centre of Expertise for Rabies, Canadian Food Inspection Agency, 3851 Fallowfield Road, P.O. Box 11300, Station H, Ottawa, Ontario K2H 8P9, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Fehlner-Gardiner
authors.affiliation: Wildlife Research and Monitoring Section, Ontario Ministry of Natural Resources, Trent University, DNA Building, 2140 East Bank Drive, Peterborough, Ontario K9J 7B8, Canada.
authors.forename: P
authors.initials: P
authors.lastname: Bachmann
authors.affiliation: Division of High-Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, 1600 Clifton Road NE, Mailstop G-33, Atlanta, GA 30329, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Ellison
authors.affiliation: Division of High-Consequence Pathogens and Pathology, Centers for Disease Control and Prevention, 1600 Clifton Road NE, Mailstop G-33, Atlanta, GA 30329, USA.
authors.forename: F R
authors.initials: FR
authors.lastname: Jackson
authors.affiliation: Wildlife Research and Monitoring Section, Ontario Ministry of Natural Resources, Trent University, DNA Building, 2140 East Bank Drive, Peterborough, Ontario K9J 7B8, Canada.
authors.forename: J S
authors.initials: JS
authors.lastname: Taylor
authors.affiliation: Wildlife Research and Monitoring Section, Ontario Ministry of Natural Resources, Trent University, DNA Building, 2140 East Bank Drive, Peterborough, Ontario K9J 7B8, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Davies
authors.affiliation: Wildlife Research and Monitoring Section, Ontario Ministry of Natural Resources, Trent University, DNA Building, 2140 East Bank Drive, Peterborough, Ontario K9J 7B8, Canada.
authors.forename: D
authors.initials: D
authors.lastname: Donovan
mesh_terms: D000256:Adenoviridae; D000284:Administration, Oral; D000818:Animals; D057134:Antibodies, Neutralizing / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood; D005589:Foxes / Q000276:immunology*; D056724:Immunity, Humoral; D011818:Rabies / Q000517:prevention & control*; D011819:Rabies Vaccines / Q000008:administration & dosage*; D014614:Vaccines, Synthetic / Q000008:administration & dosage
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D011819:Rabies Vaccines; D014614:Vaccines, Synthetic
keywords: Human adenovirus serotype 5; Immune response; ONRAB(®); Oral rabies vaccination; Rabies control; Rabies virus challenge; Red fox; Vulpes vulpes