Bait Delivery for Oral Rabies Vaccine to Gray Foxes

Abstract

Rabies is a widespread zoonotic disease that has reached epizootic proportions in gray foxes (Urocyon cinereoargenteus) in central Texas. Because each species of carnivore has different food preferences and foraging strategies, it is essential that the efficacy of a bait delivery program be examined for gray foxes prior to an oral vaccination program being attempted. Field trials were conducted to determine bait preferences of free-ranging gray foxes to selected baits and odor attractants. Baits consisted of polymer cubes made of either dog food meal or fish meal, and a wax-lard cake that was enhanced with marshmallow flavoring. Attractants added to baits exuded sulfurous, fatty, cheesy, or sweet odors and flavors. During 3,589 operable bait station nights, gray fox visitation and bait uptake rates were 9.2% and 8.3%, respectively. Gray foxes exhibited no preference in bait uptake rates between bait and odor attractant combinations. Gray foxes exhibited no difference in cumulative bait uptake rates between onroad and offroad sites; however, the uptake rate by raccoons was significantly greater for baits placed on roads than for baits randomly placed. Raccoons were the major non-target species competing for baits, being attributed with 73% of the total uptake. Visitation and bait uptake rates by raccoons significantly increased after a 7-day lethal removal of raccoons (n ϭ 37) from the study area. Random distribution of baits is recommended; it reduced bait uptake by non-target species without adversely affecting uptake by gray foxes.

Nematodes parasites of the gray fox (Urocyon cinereoargenteus Schreber, 1775) in the seasonally dry tropical highlands of central Mexico

“…However, the study of parasite communities occurring in Mexican wild mammals remains relatively unexplored (Pérez-Ponce de León 2001). Gray foxes (Urocyon cinereoargenteus, Schreber 1775), which is the most abundant wild canid species in Mexico, and considered ecological generalists because to a wide adaptive capacity to different habitats (Fritzell and Haroldson 1982;Ceballos and Galindo-Leal 1984;King and Bohning 1984;Harrison 1997;Steelman et al 1998;Steelman and Henke 2000;Buskirk 1999;Sunquist and Sunquist 2001;Crooks 2002;Gehring and Swihart 2003). There is limited information available concerning the parasite species of the gray fox, or its role as a reservoir or source of parasite outbreaks (Davidson et al 1992).…”

Pre-spillover Prevention of Emerging Zoonotic Diseases: What Are the Targets and What Are the Tools?

“…Millions of ORV doses have been delivered to control red fox rabies in Europe and raccoon rabies in the United States (Aubert 1999a(Aubert , 1999bSlate et al 2005); ORV has eliminated or reduced red fox rabies in many countries in western Europe Aubert 1999b). In the United States, deployment of ORV to reduce enzootic levels of rabies, such as gray fox-associated rabies in Texas (Steelman et al 2000), or to develop immune barriers to the spread of raccoon variant rabies and coyote/ dog variant rabies, in Ohio, West Virginia, and Pennsylvania (the Ohio barrier), and in Texas, respectively (Foroutan et al 2002;Farry et al 1998;Slate et al 2005), Steelman et al 2000;Fearneyhough et al 1998;Roscoe et al 1998;Brochier et al 1996 have established zones where herd immunity is sufficiently high that rabies virus transmission is interrupted. The Ohio barrier was effective in preventing or reducing raccoon rabies cases west of the vaccination border to a sporadic few, but after 6-7 years of success, a serious breach of the Ohio barrier, 11 km west of the vaccine zone, sparked what appears to be a new epizootic focus Anonymous.2004a).…”

Evaluation of attractant flavours for use in oral vaccine baits for badgers (Meles meles)

“…A wide range of products have been used to increase the attractiveness of baits for wild mammals; strawberry (cotton wool impregnated with a strawberry flavouring) has been used successfully as an attractant for feral swine (Campbell and Long 2009), cinnamon-truffle powder (as a bait additive) for feral swine piglets (Ballesteros et al 2009), apple (both apple juice and apple odour) for white-tailed deer (Bean and Mason 1995), marshmallow (as a bait flavouring) for gray foxes (Steelman et al 2000) and cinnamon oil and anise oil (as bait additives) for brushtail possums (Morgan 1990;Aldwell et al 2003a). Fish products have worked well as attractants for raccoons , skunks (Jojola et al 2007), mongooses (Creekmore et al 1994) and red foxes (Smith and Woods 2007), whereas offal has proved a useful attractant for dogs (Estrada et al 2001) and coyotes (Stolzenburg and Howard 1989).…”