African Swine fever - epidemiological considerations and consequences for disease control

African swine fever (ASF) has reached the eastern borders of the European Union early in the year 2014. The very first cases have been reported by Lithuania and Poland, followed by Latvia in June and Estonia later in September of that same year. The outbreaks occurring in domestic pigs have been controlled timely and without major problems. Within the wild boar population however, the occurrence of ASF has shown to be very complex and difficult to control. Field data as well as experimental studies on ASF indicate an overall high case fatality rate and a rather low contagiosity. For disease control in domestic swine populations the low contagiosity is an advantageous feature reducing the urgency in the implementation of control measures. For wild boar however, in combination with the environmental stability of the virus and high animal densities, the low contagiosity represents a disadvantage for effective control. Within that context, a revision of the current understanding and approaches towards ASF control in wild boar is needed. Current findings indicate that in wild boar populations ASF shows a pattern of longer, habitat bound persistence lacking a tendency of dynamic spatial spread. In analogy to Anthrax where spores of Bacillus anthracis are considered soil borne, ASF in wild boar can be considered a "habitat-borne disease" where carcasses of affected animals play a key role in binding the disease within affected areas. These carcasses, in combination with the virus tenacity and the low contagiosity are likely to contribute substantially to months or even years of pathogen persistence explaining the current picture of ASF spreading rather slowly and with continuing circulation in affected areas.