Transient classical swine fever virus infection in wild boar piglets partially protected by maternal antibodies

An experimental study was conducted to investigate the clinical course of classical swine fever (CSF) in wild boar piglets partially protected by maternal antibodies. Five healthy wild boar piglets with a low serum titre of colostral antibodies against CSF virus were challenged with virulent CSF virus at the age of three months. Apart of reduced food intake and diarrhoea no major clinical symptoms were noticed after challenge. These signs were seen during the second and third week of infection, afterwards the piglets recovered completely. CSF virus could be re-isolated from blood samples taken on day 12 and day 19 post challenge. From blood samples taken later on and from the organ material taken at post mortem examinations no CSF virus could be isolated anymore. It can be concluded that the presence of maternal antibodies influences the clinical course of CSF in terms that the outcome is rather transient than lethal. Such wild boar could play a crucial role in the spread of CSF virus and might contribute to the maintenance of long lasting epizootics.