"Ferreira’s study shows that there is a first period in which infected pigs secrete large amounts of ASFV, especially via saliva, but also via faeces. In this period the virus is transmitted efficiently to other pigs via direct contact. This first phase is followed by a long period (several months) in which the virus is excreted only occasionally, and therefore in that period other pigs may still become infected. "

http://www.wageningenur.nl/nl/show/PhD-Defence-Transmission-mechanisms-of-African-swine-fever-virus.htm

"Ferreira also demonstrated the presence of virus particles in the air of rooms housing infected pigs. Over short distances this may cause transmission of the virus to other pigs. Furthermore, Ferreira demonstrated that the virus can only survive for a few days in the environment, outside the animal. And finally, Ferreira’s study shows that the two most common species of hard ticks in Europe are unlikely vectors of ASFV, contrary to the soft ticks in Africa."