Table 1.

^aEpidemiological scenarios, by geographical area.

Geographical area	Species involved	Route of transmission	Risk factors for persistence or spread	Other areas with an overlapping scenario
Eastern and Southern African countries (currently)	Wild suids (asymptomatic Phacochoerus and Potamochoerus spp.), Soft ticks (O. moubata as reservoir) Domestic pigs (34)	Sylvatic warthog–tick cycle and/or domestic-tick or domestic pig cycle (38). Transmission to domestic pigs through the bite of infected ticks and the ingestion of tissues from acute-infected warthogs. Movement of infected pigs and products (38).	Low biosecurity in pig farms, marketing of infected pigs and products, cultural constrains (38), human behavior (8). Relevant role of soft tick and wild pigs in the maintaining of the disease.	N.A.
West African countries (currently)	Domestic pigs. Ticks suspected not to be involved A sylvatic cycle has never been demonstrating (34, 39).	Direct contact between domestic pigs (infected-not infected) Indirect contact between not infected pigs and infected pork products	Socioeconomic factors: lack of compensation to farmers (underreporting); lack of veterinary services, low biosecurity farms with home slaughter with indiscriminate disposal of pig viscera, swill feeding, illegal selling of infected pigs and pork products, cultural practices (39).	The same as in some areas of the Caucasus and the Russian federation
Russian Federation and trans-Caucasian countries (currently)	Domestic pigs and wild suids (Sus scrofa)	Movement of infected/carrier animals (direct contact between wild boars and domestic pigs) Transmission within wild boar population. Movement of infected products.	Lack of compensation for slaughtered animals; lack of resources for adequate control measures; lack of traceability; delays in identification of new cases; non-compliance with movement bans; farms with poor biosecurity.	N.A.
Sardinia (currently)	Domestic pigs, and wild suids (Sus scrofa) No ticks found	Movement of infected/carrier animals (direct contact between domestic pigs and wild boars/non-registered domestic pigs).	Arduous natural habitats (hard access). Traditional breeding practices (free ranging pigs or “brado” illegally maintained in demanial areas) (40).	N.A.
Baltic Republicsb	Mainly wild suids (Sus scrofa) Domestic pigs	Uncontrolled movement of infected pigs, pigswill with ASFV. Spread through the continuous wild boar population habitat. Direct/indirect contact between domestic pigs and wild boars (41).	Contamination of wooded areas where infected carcasses of dead wild boars lied for several months. Association between the number of settlements, the human population size as well as the number of domestic pigs and pig farms, roads, forest cover percentage, and the presence of ASF in wild boar (26). Long jumps spread in wild boars likely by human activity (38) Lithuania: lack of biosecurity in the non-commercial pig farms (41). Estonia: contaminated fomites, vehicles, or clothing of farm workers (41).	N.A.
Eastern Europec	Mainly domestic pigs Wild suids (Sus scrofa) No ticks found		Small/backyard pig farms (21, 38). Involvement of humans in the disease spread in Poland, Bulgaria (41).	N.A.

^aThe table was created by the use of information (modified and updated) provided by Sánchez-Vizcaíno et al. (7).

^bBaltic Republics: Latvia, Lithuania, Estonia.

^cEastern Europe: Belarus, Bulgaria, Hungary, Moldova, Ukraine, Slovakia, and Poland (belonging to Central Europe).