The persistence of African swine fever in Africa and the Mediterranean

Abstract

African swine fever (ASF) virus is maintained in Africa primarily by a cycle of infection between wart hogs and soft ticks (Ornithodoros moubata) in which ticks may become infected by feeding on young wart hogs, which are viraemic for only a short period after birth. Infected ticks constitute a permanent reservior of infection for domestic pigs, which may become infected by the bite of infected ticks or the ingestion of infected wart hog tissues. In the Mediterraean region, ASF in enzootic in Spain, Portugal and Sardinia. The main factors contributing to persistence in the Iberian peninsula are the difficulty of detecting disease caused by the newer, less virulent viruses, extensive systems of husbandry, increased production and trade in pigs, the excess concentration of pig farms in certain areas and the presence of soft tick vectors (Ornithodoros erraticus) in the south-west.