Oral immunisation of wild boar against classical swine fever: uptake studies of new baits and investigations on the stability of lyophilised C-strain vaccine

Abstract

The aim of this study was to investigate the uptake of new spherical and cuboid baits by wild boar and domestic pigs and to evaluate the stability of lyophilised C-strain vaccine stored at different environmental temperatures. New baits were designed to improve the consumption of the vaccine against classical swine fever by young wild boar. Our uptake studies showed that neither wild boar nor domestic pigs at the age of 2 months picked up the baits at all. Although the animals began to pick up the baits incompletely at the age of 3 months, a complete uptake of both the new baits and the older ones was only observed from the age of 4 (domestic pigs) and 4.5 (wild boar) months on. Nevertheless, the larger spherical baits with a diameter of 3 cm were taken up more effectively than the recent vaccine baits. As expected, lyophilised vaccine showed a higher stability than liquid vaccine, especially at temperatures ≥24°C. Independently of the stabiliser (GS4 or TSM) used, there are no differences between the virus titres detected within a storage period of 7 days. As the lyophilised C-strain vaccine was more stable at higher temperatures than the liquid vaccine formulation, we recommend to use lyophilised vaccine for oral immunisation of wild boar in the future, as oral vaccination is also carried out in the summertime.

Specificity and success of oral-bait delivery to Eurasian wild boar in Mediterranean woodland habitats

“…The total eradication of a disease is very difficult if a wildlife host is able to serve as a natural reservoir of the pathogen . Hence, the eradication of diseases shared between livestock and wildlife may require the development of control strategies that reduce pathogen transmission between wildlife and domestic animals using vaccination or by reducing host density (Brauer et al 2006;Ballesteros et al 2007;Cross et al 2007).…”

“…Baiting with oral vaccines is also used for wildlife disease control (Baer 1976;Cross et al 2007). However, the effective and efficient field vaccination of wildlife species requires the development of stable and speciesspecific baits as delivery vehicles for oral vaccines (Brauer et al 2006;Ballesteros et al 2007) and designing appropriate baiting strategies (Vos et al 2008). In Spain, controlled vaccination trials are being conducted to eventually use wildlife vaccination as a disease management tool for Aujeszky's disease and bTB (Ballesteros et al 2009c).…”

Control and eradication of Classic Swine Fever in wild boar

“…MDAs usually have disappeared within 3 months of birth (Kaden and Lange, 2004a;Soos et al,2001) but low levels of MDAs have been also detected for longer periods (Depner et al, 1995a, Müller et al, 2005. Wild boar piglets, before the age of 3 months do not consume the vaccine baits (Brauer et al, 2006).…”

“…four weeks (Kaden et al, 2003). The schedule aims to maximize the individual antibody titre (Kaden et al,2004a) and to reach young wild boar that are not eating regular baits before at least 4.5 months (Brauer et al, 2006). A density of 2 vaccination places per km² is recommended were 20 to 40 baits are delivered each time (Kaden et al, 2001b;von Rüden et al, 2008).…”

An assessment of the applicability of dung count to estimate the wild boar population density in a forest environment

“…After the World War II the wild boar started recolonisation of the Czech Republic and its steadily growing population presents a serious economic, ecological and social threat across central Europe (Frank 2008;Kirschning et al 2008). The most serious consequences of the increase in wild boar density are damage to agricultural crops, road accidents, transmission of infectious diseases and the destruction of managed green space in populated areas (Geiser 1998;Brauer et al 2006;Herrero et al 2006;Acevedo et al 2007). …”