Prevalence of Tetracycline and Rabies Virus Antibody in Raccoons, Skunks, and Foxes Following Aerial Distribution of v-Rg Baits to Control Raccoon Rabies in Ontario, Canada

Abstract

More than 3.6 million baits containing a recombinant vaccinia virus-rabies glycoprotein (V-RG) oral rabies vaccine were aerially or hand-distributed during 1999-2006 in an approximate 4,000-9,000 km(2) area of eastern Ontario, Canada, as part of a multitactic approach to control the raccoon variant of rabies. The efficacy of the program was assessed through the collection and testing of > 6,900 animals for bait acceptance and rabies virus-specific antibodies. Raccoon acceptance of rabies vaccine baits was significantly greater (71-83% ) in areas baited at a density of 150 baits/km(2) compared to areas baited at 75 baits/km(2) (26-58% ), and more raccoons consumed vaccine baits in areas baited with a flight line spacing of 0.75 km (45.3% [321/708]) than with a spacing of 1.5 km (33.8% [108/320]). In addition, greater numbers of raccoons consumed vaccine baits during a drop in September (52.7% [213/404]) as opposed to a June bait drop (34.6% [216/624]). Seropositivity rates for raccoons ranged between 7% and 28% in areas baited at 75/km(2) and 10% to 27% in areas baited at 150/km(2) with statistical differences varying among years and treatments. The last case of raccoon-variant rabies reported in Ontario was in September 2005. The control of raccoon rabies in Ontario has resulted in an estimated $6M to $10 M Cdn annual savings in rabies-associated costs.

Oral Rabies Vaccination Variation in Tetracycline Biomarking Among Ohio Raccoons

“…Variation in the number of baiting episodes among years; time-lags between bait distribution, bait uptake, and sample collection; raccoon population density, age structure (Linhart and Kennelly, 1967), and sex (Buyske et al, 1960); and condition and age of tetracycline within bait lots may be confounding. In Ontario, Rosatte et al (2008) found age effects in some, but not all, years for samples they studied, suggesting variation in this phenomenon within populations.…”

“…Tetracycline hydrochloride (tetracycline) is a commonly used compound for this purpose, and is detectable 2-5 days postconsumption (Hanlon et al, 1989) by ultraviolet microscopy of crosssectioned teeth . Consequently, tetracycline has an extensive history of use in oral vaccination and predator control (Linhart and Kenelly, 1967;Hanlon et al, 1989;Bachmann et al, 1990;Hable et al, 1992;Creekmore et al, 1994;Farry et al, 1998;Johnston et al, 2005;Slate et al, 2005;Ramey et al, 2008;Rosatte et al, 2008). More specifically, tetracycline has been used to assess bait uptake as part of oral vaccination campaigns and research in red foxes (Vulpes vulpes; Johnston and Voight, 1982;Niin et al, 2008), striped skunks (Mephitis mephitis; Johnston and Voight, 1982), raccoons (Procyon lotor; Rupprecht et al, 1987;Rosatte et al, 2009), coyotes (Canis latrans; Linhart and Kinelly, 1967), raccoon dogs (Nyctereutes procyonoides; Niin et al, 2008), and feral swine (Sus scrofa; Campbell et al, 2011).…”

The field efficiency of oral rabies vaccination in the Lithuanian red fox population from 2006 to 2013

“…Likewise, the number of rabies cases has rapidly decreased in all three Baltic States since 2006; for instance, rabies has been nearly eradicated in Estonia since summer 2009 (Cliquet et al 2012). Levels of the TTC marker during the different ORV seasons were comparable for spring and autumn campaigns, and showed an increasing tendency (7-28%) throughout the period studied, suggesting a cumulative exposure to distributed baits (Rosatte et al 2008). Juvenile red foxes appeared to have lesser access to baits, which confirms earlier studies with similar results (Rosatte and Lawson 2001).…”

Evolutionary perspectives on wildlife disease: concepts and applications

“…While vaccines are often among the tools available to wildlife managers (Wobeser ); e.g., raccoon rabies variant (Rosatte et al. ), tuberculosis (Tompkins et al. ), brucellosis (Cross et al.…”

“…Vaccines selecting for increased virulence have important evolutionary implications for malaria (Mackinnon et al 2008) and human papilloma virus vaccination programs (Stearns 2012). While vaccines are often among the tools available to wildlife managers (Wobeser 2002); e.g., raccoon rabies variant (Rosatte et al 2008), tuberculosis (Tompkins et al 2013), brucellosis , their impermanence, and their role as selective agents are rarely considered.…”