Progress towards Bait Station Integration into Oral Rabies Vaccination Programs in the United States: Field Trials in Massachusetts and Florida

Abstract

Bait stations for distribution of oral rabies vaccine baits are designed for rabies management in highly-developed areas where traditional distribution of oral rabies vaccine baits may be difficult. As part of national efforts to contain and eliminate the raccoon (Procyon lotor) variant of the rabies virus (raccoon rabies) in the eastern United States, the United States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services program, distributed vaccine baits by bait stations experimentally and operationally in Massachusetts during 2006-present, and in Florida during 2009–2015. In Massachusetts, a rabies virus-neutralizing antibody (RVNA) response of 42.1% for raccoons captured in areas baited with high density bait stations during 2011–2015 was achieved, compared with 46.2% in areas baited by hand, suggesting the continuation of this as a strategy for the oral rabies vaccination (ORV) program there, and for similar locations. Non-target competition for vaccine baits is problematic, regardless of distribution method. In Massachusetts, bait station visitation rates for targeted raccoons and non-target opossums (Didelphis virginiana) were similar (1.18:1) during 2006–2009 (p > 0.05). Bait station modifications for reducing non-target uptake were tested, and in Massachusetts, reduced non-target bait access was achieved with two design alternatives (p < 0.001). However, no difference was noted between the control and these two alternative designs in Florida. Due to ongoing trials of new vaccines and baits, the bait station performance of an adenovirus rabies glycoprotein recombinant vaccine bait, ONRAB® bait (Artemis Technologies, Guelph, ON, Canada) and a vaccinia-rabies glycoprotein recombinant vaccine bait, RABORAL V-RG®bait (Merial Limited, Athens, GA, USA), was compared. While uptake of the ONRAB bait was greater in Massachusetts (p < 0.001) in this limited trial, both types performed equally well in Florida. Since bait station tampering or theft as well as potential human bait contacts has been problematic, performance of camouflaged versus unpainted white bait stations was analyzed in terms of internal temperatures and maintaining a stable bait storage environment. In Massachusetts, camouflaged bait station interiors did not reach higher average temperatures than plain white bait stations in partially- or fully-shaded locations, while in Florida, camouflaged bait stations were significantly warmer in light exposure categories (p < 0.05). As ORV operations expand into more heavily-urbanized areas, bait stations will be increasingly important for vaccine bait distribution, and continued refinements in the strategy will be key to that success.

Rabies control in North America – past, present and future

“…This is less labour intensive but has other potential problems, such as non-target competition for baits, or tampering by people. Measures to mitigate such issues have been evaluated in field trials in New York, Florida and Massachusetts (87,116).…”

Oral Rabies Vaccination of Raccoons (Procyon Lotor) Across a Development Intensity Gradient in Burlington, Vermont, Usa, 2015–2017

“…A comprehensive ecological understanding may inform refinement of baiting strategies for raccoons in urban and suburban environments. Bait stations require additional study, such as incorporating them with hand baiting, locating them farther from roads to potentially bolster bait encounters as suggested by (Bigler et al 2021b), and expanding on work by Bjorklund et al (2017) to improve specificity of access by raccoons. Bigler et al (2021b) found significantly greater raccoon seroconversion from helicopter bait distribution when compared to vehicle (hand) distribution.…”

A Global Perspective on Oral Vaccination of Wildlife Against Rabies

“…Such emergency responses were expensive, involving ERS activities, additional bait drops (e.g., twice a year), or higher bait densities (e.g., 150-300 baits/km 2 ), augmented with additional methods (e.g., TVR). To maximize raccoon vaccination and to help minimize bait contact by nontarget species such as humans, domestic cats, or opossums (Didelphis virginiana), bait stations were employed, particularly in suburban and urban environments (Boulanger et al 2006;Bjorklund et al 2017;Haley et al 2017;Bastille-Rousseau et al 2024).…”