Update on oral vaccination of foxes and raccoon dogs against rabies

Abstract

An assessment of a report issued by the European Commission in 2002 is presented about the oral vaccination of foxes against rabies, as well as additional topics such as the rabies aetiology and its occurrence in Europe, the target species for oral vaccination, i.e. foxes and raccoon dogs, the oral vaccines available and their thermostability, rabies surveillance and monitoring, and the recent international guidelines for rabies surveillance are discussed. Foxes are the only known reservoir for rabies in Europe, and raccoon dogs are important transmitters, while other carnivores play a less important epidemiological role. The demographic expansion of raccoon dogs and their movements after hibernation are risk factors for rabies recurrence. The combined densities of foxes and raccoon dogs, which often share the same habitats, could allow rabies epizootics to persist. The epidemiological role and the pathogenesis of rabies in raccoon dogs and other carnivores must still be clarified. Four vaccines are authorised in the EU and their effectiveness is proven to successfully contribute to rabies elimination. Experimental and field evidence shows that climatic and weather conditions may impact on bait casings and vaccine stability. Data on the stability of vaccine baits under different field conditions should be provided. It is recommended that bait should keep its integrity at the release point. Because of bait stability issues, the season most appropriate for implementing oral rabies vaccination or a heat-stable vaccine should be considered. Rabies surveillance and monitoring of vaccination, based on assessment of bait uptake and seroconversion in host species, are important tools for the evaluation and adjustment of vaccination campaigns, although alternatives to tetracyclines as biomarkers should be developed. Oral immunisation by vaccine baits has proven to be successful in eliminating terrestrial wildlife rabies, but long-term strategy, temporal continuity of vaccination and cross-border cooperation are needed and recommended. Acknowledgements:The Panel wishes to thank Florence Cliquet, Paola De Benedictis, Kaarina Kauhala, Edvīns Oļševskis, Liisa Sihvonen (Chair) and Marcin Smreczak for the preparatory work on this scientific output, the hearing expert Thomas Müller and EFSA staff members Alessandro Broglia and Marianne Carson for the support provided to this scientific output. Suggested citation: EFSA AHAW Panel (EFSA Panel on Animal Health and Welfare), 2015. Scientific opinion -Update on oral vaccination of foxes and raccoon dogs against rabies.

Optimizing spatial and seasonal deployment of vaccination campaigns to eliminate wildlife rabies

“…We found that consecutive and coordinated vaccination across geographical regions is required to rapidly control and eliminate rabies. This confirms previous findings [8] and is in accordance with EU recommendations [18], appearing to result from the need to maintain sufficient herd immunity in the face of seasonal birth pulses. Autumn vaccination campaigns had a greater impact on increasing the probability of elimination and reducing time to elimination across a range of epidemiological scenarios.…”

“…relation to demographic processes should be explored, taking into account appropriate practical considerations. For fox rabies, timing of ORV campaigns was determined based on factors including immune competence [21,22], vaccine sensitivity to high temperatures [23], levels of herd immunity and deployment costs [18]. Connectivity generally plays a key role in disease persistence [24,25] and the size of host populations influences time to control [26].…”

“…Rabies-free regions that are contiguous with endemic areas are vulnerable to reintroduction. Incursions from neighbouring endemic areas pose a serious risk to rabies freedom and highlight the need for coordinated cross-border activities [18] as evidenced by incursions seen in Europe (France -Switzerland (1990), France -Belgium -Germany (1993), Italy -Slovenia -Austria (1993), Germany -Poland-Czech Republic (1995) and Italy -Slovenia (2008) [27 -30] and their successful control [27,31,32]). Our results show that large and well-connected regions (i.e.…”

Zero Endemic Cases of Wildlife Rabies (Classical Rabies Virus, RABV) in the European Union by 2020: An Achievable Goal

“…Finally, a key reference is the scientific report on the oral vaccination of foxes against rabies [34], covering the practical and organizational aspects to consider. The European Food Safety Authority (EFSA) updated this report with scientific panels in 2010 [35] and 2015 [36]. Such guidelines were drafted in line with WHO and OIE rabies recommendations [7,[37][38][39][40][41].…”

“…As the golden jackal (Canis aureus) could be a potential host [43], and following its recent geographical expansion [44], this species has been included since a few years of the monitoring of vaccination effectiveness. ORV campaigns are classically undertaken by aerial distribution of the vaccine baits twice a year, at a density around 20-25 baits/km 2 [34][35][36]. Campaigns are organized in spring and autumn to match with the red fox biology [45] and optimal temperature conditions.…”