Controlling of CSFV in European wild boar using oral vaccination: a review

Abstract

Classical swine fever (CSF) is among the most detrimental diseases for the swine industry worldwide. Infected wild boar populations can play a crucial role in CSF epidemiology and controlling wild reservoirs is of utmost importance for preventing domestic outbreaks. Oral mass vaccination (OMV) has been implemented to control CSF in wild boars and limit the spill over to domestic pigs. This retrospective overview of vaccination experiences illustrates the potential for that option. The C-strain live vaccine was confirmed to be highly efficacious and palatable baits were developed for oral delivery in free ranging wild boars. The first field trials were performed in Germany in the 1990’s and allowed deploying oral baits at a large scale. The delivery process was further improved during the 2000’s among different European countries. Optimal deployment has to be early regarding disease emergence and correctly designed regarding the landscape structure and the natural food sources that can compete with oral baits. OMV deployment is also highly dependent on a local veterinary support working closely with hunters, wildlife and forestry agencies. Vaccination has been the most efficient strategy for CSF control in free ranging wild boar when vaccination is wide spread and lasting for a sufficient period of time. Alternative disease control strategies such as intensified hunting or creating physical boundaries such as fences have been, in contrast, seldom satisfactory and reliable. However, monitoring outbreaks has been challenging during and after vaccination deployment since OMV results in a low probability to detect virus-positive animals and the live-vaccine currently available does not allow serological differentiation of infected from vaccinated animals. The development of a new marker vaccine and companion test is thus a promising option for better monitoring outbreaks during OMV deployment as well as help to better determine when to stop vaccination efforts. After rabies in red fox, the use of OMV against CSF in European wild boar can be considered as a second example of successful disease control in wildlife. The 30 years of disease control experience included in this review may provide options for improving future disease management within wild populations.

Current status and evolving approaches to African swine fever vaccine development

“…Thus, it is equally important to define feasible and acceptable vaccination strategies in view of the target population, considering how and when vaccination should be used, and other socio‐economic factors. Vaccination experiences in wild boar population against classical swine fever (CSF) through palatable baits or oral vaccines and other diseases have worked well and could be used as a basic model to develop vaccination strategies against ASF (Rossi et al, ); however, due to diversified genetic background of ASFV, there may be challenges, and therefore, vaccination strategies should be directed in response to predicted epidemics, based on epidemiological scenarios and disease control strategies.…”

Epidemiology, diagnosis and control of classical swine fever: Recent developments and future challenges

“…Introduction and spread of the disease are greatly influenced by human activities such as transport and trade of pigs and pig products as well as pig density. Numerous studies have been conducted on spatial spread and dynamics of CSF in domestic pigs and wild boar (Elbers et al., ; Fritzemeier et al., ; Rossi et al., ; von Ruden et al., ; Stegeman, Elbers, Boum, & de Jong, ). As soon as an outbreak is detected, a high level of preparedness including contingency plans and the implementation of control measures will contribute to interrupt the spread.…”

“…In addition to their wide use as injection vaccines for domestic pigs, live CSF vaccines can be used for wild boar as oral vaccines (Kaden & Lange, ; Kaden, Schurig, & Steyer, ; Rossi et al., ). The historical view that CSF outbreaks in wild boar are self‐limiting is questionable, at least for high‐density wild boar populations (Moennig & Becher, ; Terpstra, ).…”

“…For immunization of wild boar, the baits cannot be distributed by planes as known for oral vaccination of foxes against rabies. The development and production of improved type of baits for wild boar is not yet completely solved (Rossi et al., ).…”

Baiting studies on oral vaccination of the greater kudu (Tragelaphus strepsiceros) against rabies

“…Sometimes, new strategies like clustered baiting using for example bait stations are used (Boulanger et al 2006). These techniques are also applied for wild boars (Sus scrofa), a species with a similar social structure as kudus (Ballesteros et al 2011;Rossi et al 2015). Unfortunately, most of these bait distribution systems are not suitable for targeting kudus in Namibia.…”