Probability of infection
We found a positive relationship between the probability of ASF infection and the proportion of infected individuals in high-, medium-, and low-contact zones (0-2km, 2-5km, and 5-10 km, respectively) (Supplementary Information, Table S1, Fig. S2). The strongest effect of the proportion of infectees was observed in the high-contact zone, where infection risk increased from 2.5 % if no infected individuals were present to 96 % if all other individuals were ASF-positive. Proportion of infected individuals at distances over 10 km did not influence the probability of infection (Table S1, Fig. S2). Relatedness was a positive predictor of infection risk within 10 km but had no effect at larger distances (Table S1, Fig. S2). Probability of infection among kin (i.e. presumably group members) across the study area was on average 77 ± 1.5% (min-max: 69-87) within 10 km, while infection risk among non-kin averaged 52 ± 0.9% (min-max: 28-68) within 10km (Fig. S2a). Models combining relatedness and proximity to infected individuals (Table 2) showed that the relative contribution of relatedness and proportion of infected individuals to explaining variation in infection probability varied with distance. In the high-contact zone, variation in infection risk was shaped overwhelmingly by the proportion of infected individuals and not by relatedness (Table 2, Fig 3). However, infection risk among kin within 2 km distance was high. All of the animals which were surrounded by ASF-positive kin (n = 17) tested positive, while none of the animals surrounded by ASF-negative kin (n = 7) tested positive. Among animals surrounded only by infected non-kin between 0 and 2 km (n = 18), the proportion of ASF-positive individuals was 83%, indicating they were 17% less likely to become infected by non-kin relative to kin on average. At further distances of 2-5 km (medium-contact zone) infection risk increased with both relatedness and proportion of ASF-positive individuals at this distance (Table 2, Fig.3), indicating that ASF transmission was significantly more likely between related individuals. In the medium-contact zone, infection risk averaged 84 ± 3.5% (min-max: 58-93) among kin and 47 ± 2.5% (min-max: 16-81) among non-kin. At even further distances of 5-10 km (low-contact zone), probability of infection increased with the number of ASF-positive individuals while relatedness to infectees did not shape infection risk. Here, infection risk increased from 38 % if at least one infected individual was present to 75 % if all other individuals were ASF-positive (Fig. 3). At distances >10 km (no-contact zone), neither relatedness to infected individuals nor their number influenced infection risk (Table 2, Fig.3).